A recent livestream interview, billed as an exposé of “the great supplement scam,” made a series of claims about vitamin B12 that deserve a full, careful, permanent debunking. The guest, a 45-year vegan author, told viewers that B12 was essentially invented in a Merck laboratory, that deficiency symptoms are really chemical poisoning misattributed to a vitamin, that the cyanide in cyanocobalamin should scare you, that he hasn’t had a blood test in 50 years and knows he’s healthy because he feels great, and (most dangerously) that vegans should not only skip B12 supplements but actively seek out unfortified nutritional yeast to avoid the B12 that’s been added to foods.

This post takes those claims apart one at a time, using the full hierarchy of scientific evidence: consensus statements, systematic reviews and meta-analyses, randomized controlled trials, cohort studies, case series, and the underlying biochemistry. It also addresses the conspiracy framing head-on, because the “follow the money” story collapses under one inconvenient, well-documented fact: the single biggest customer of the vitamin B12 industry is animal agriculture itself [29, 30]. And it closes with exactly what the evidence says vegans should do, covering doses, forms, and testing, so that nobody reading this ever has to gamble.

One thing before we start. I’m writing this as an advocate for plant-based eating. The people who most need this information are vegans, and the people most harmed by the video’s advice are vegans, including, in the worst documented cases, vegans’ babies [13]. Debunking B12 denial isn’t an attack on veganism. It’s a defense of it.

The claims on the table

Distilled from the interview, here is what was asserted:

1. Vegans don’t need vitamin B12.
2. B12 was “invented” or fabricated in a Merck laboratory as part of a profit scheme.
3. B12 deficiency isn’t real: the symptoms attributed to it are actually caused by environmental chemical exposure.
4. The fact that B12 is the one vitamin you can’t get from fruits and vegetables is suspicious, and is evidence of an agenda to push people toward meat, dairy, and pills.
5. Cyanocobalamin contains cyanide, so taking it means knowingly consuming poison.
6. Vitamins in general are “refined petroleum,” petrochemicals one step removed from pharmaceuticals.
7. The speaker’s own health after 45 years as a vegan, much of it without supplements (no doctor visits in 50 years, no blood tests, a “biological age of 22” from balance and grip-strength tests), proves supplementation is unnecessary, and healthy centenarians in places like Okinawa have “terrible” blood levels yet thrive, so blood markers are meaningless.
8. Follow the money: the pharmaceutical-supplement complex profits from the B12 narrative, and vegan doctors who recommend it have been “too gullible.”

Plus one piece of practical advice: don’t supplement, and buy unfortified nutritional yeast specifically to avoid added B12.

Every one of these fails. Let’s establish how we’ll know that, and then go claim by claim.

First, the ground rules: how the hierarchy of evidence works

What is the hierarchy of scientific evidence?

Science doesn’t treat all information equally. At the bottom of the evidence pyramid sit anecdotes, testimonials, and expert opinion: “I’ve been fine for 45 years.” One step up is mechanistic reasoning and lab findings. Then case reports and case series, which document individual patients. Then observational studies: cross-sectional surveys and prospective cohorts following thousands of people over years. Above those sit randomized controlled trials (RCTs), where an intervention is tested against a placebo with neither participants nor researchers knowing who got what. At the top are systematic reviews and meta-analyses that pool every available trial, and the consensus statements of expert bodies that weigh all of it together.

The reason the pyramid is shaped that way is simple: each step up removes more ways of fooling yourself. Anecdotes can’t distinguish luck from causation. Observational studies can’t fully separate correlation from confounding. RCTs can. Meta-analyses check whether RCTs agree with each other.

Why isn’t one person’s testimony proof?

Notice what the interview’s entire case rests on: one man’s anecdote, the bottom rung, plus a conspiracy theory whose only function is to explain away every rung above it. That’s not an alternative body of evidence. It’s a request to exempt one belief from evidence entirely.

The case for B12, by contrast, is supported at every level of the pyramid, and we’ll climb the whole thing.

What vitamin B12 actually is, in ninety seconds

What does vitamin B12 do in the body?

Vitamin B12 (cobalamin) is a cobalt-centered molecule made only by certain bacteria and archaea, not by plants, and not by animals [1, 27, 28]. In human biochemistry it is a cofactor for exactly two enzymes, and both matter enormously [1, 2].

Methionine synthase converts homocysteine into methionine, feeding the methylation reactions that maintain DNA, proteins, lipids, and neurotransmitters. When B12 runs short, homocysteine (a metabolite associated with stroke, cognitive decline, and cardiovascular risk) backs up in the blood [22, 23], and DNA synthesis in rapidly dividing cells falters. In the bone marrow, that produces the hallmark megaloblastic anemia: oversized, malformed red blood cells, plus fatigue, glossitis, and low blood counts [1, 2].

Methylmalonyl-CoA mutase handles a step in fatty-acid and amino-acid metabolism. When B12 is missing, its substrate spills over as methylmalonic acid (MMA), which is why elevated MMA is the single most specific laboratory fingerprint of B12 deficiency [1, 2].

What are the symptoms of B12 deficiency?

B12 also maintains the myelin sheath insulating your nerves. Deficiency causes numbness and tingling in the hands and feet, balance problems, and, if untreated, subacute combined degeneration of the spinal cord, with damage visible on MRI [18], progressing in advanced cases to vision loss, psychiatric symptoms, and dementia [1, 2]. Two facts make this especially unforgiving: the neurological damage can occur without any anemia to warn you, and past a certain point it can be permanent [1, 2].

How long does it take to become B12 deficient?

Now the kinetic detail that explains almost everything about this controversy: your liver stores roughly 1 to 5 milligrams of B12 against a daily requirement of about 2.4 micrograms, somewhere between a year and several years’ worth, and the reserve drains slowly because the body loses only about 0.1 percent of its stores a day and recycles more through bile [2, 56]. The U.S. National Institutes of Health states plainly that deficiency symptoms can take years to appear after intake stops [2]. Keep that number in mind. It is the reason “I feel fine” is exactly what a person sliding toward deficiency is expected to say, right up until they don’t.

Claim 1: “Vegans don’t need B12”

Let’s climb the pyramid.

What do health authorities actually say about vegans and B12?

The U.S. Institute of Medicine set the adult RDA at 2.4 micrograms per day in 1998 [3]. The German-Austrian-Swiss (D-A-CH) nutrition societies raised their reference value to 4.0 micrograms per day in 2019 after reviewing newer biomarker data [4]. The Academy of Nutrition and Dietetics, the largest body of nutrition professionals in the world, reaffirmed in its current position paper, updated in 2025, that appropriately planned vegan dietary patterns can be nutritionally adequate and offer long-term health benefits, and that vegans need a reliable source of B12 from fortified foods or supplements [5]. (The 2025 update scoped its formal position statement to adults; it simply did not undertake to review children and pregnancy this cycle, which is a limit on what the paper assessed, not a reversal of the long-standing conclusion, echoed by the NIH and by vegan dietitians below, that well-planned vegan diets are appropriate across the lifespan with a B12 source in place.) The NIH’s Office of Dietary Supplements lists vegans and the infants of unsupplemented vegan mothers among the groups at defined risk of deficiency [2]. VeganHealth.org, run by vegan registered dietitians as a project of Vegan Outreach, calls B12 “arguably the most important nutrient in vegan nutrition” and describes the necessity of supplementation as the overwhelming consensus of both mainstream nutrition science and vegan health professionals [33]. In 2001, an open letter titled “What Every Vegan Should Know About Vitamin B12” was signed by a long list of vegan health professionals and vegan organizations saying the same thing [34]. These are not meat-industry fronts. They are the vegan movement’s own institutions.

What do the systematic reviews show?

The definitive modern review of B12 deficiency, Green and colleagues in Nature Reviews Disease Primers, lays out the biochemistry, epidemiology, and clinical course in exhaustive, multi-author detail [1]. A systematic review by Pawlak and colleagues of serum B12 across vegetarian and vegan populations found high deficiency prevalence in every age group studied among those not using a reliable source, in some cohorts affecting the large majority [20]. Rizzo and colleagues’ review of B12 among vegetarians reaches the same conclusion and details assessment and supplementation strategy [19].

Is there randomized controlled trial evidence for B12?

This is where the “it’s all confounded” excuse dies. In a 12-week randomized, double-blind, placebo-controlled trial in vegans, a B12-fortified toothpaste (B12 and literally nothing else, against an identical placebo paste) significantly improved serum B12 and holotranscobalamin, and lowered MMA [16]. The same design in older adults produced the same result [17]. A 2018 Cochrane systematic review of RCTs found high-dose oral B12 comparable to intramuscular injections at normalizing status in deficient patients [6], building on the landmark 1998 randomized trial by Kuzminski and colleagues [7]. Add a single micronutrient, change nothing else, and deficiency markers normalize against placebo. That is causation, demonstrated.

What do studies of real vegans find?

One of the earliest studies of vegans, from the U.K. in 1955, documented overt deficiency among unsupplemented vegans, including nerve damage and dementia [33]. In the decades since, study after study of vegans not using supplements or fortified foods, including raw-food vegans specifically [15], macrobiotic communities, and long-term vegans in multiple countries, finds depressed serum B12, elevated MMA, and elevated homocysteine, while vegans who supplement show healthy values, frequently better than meat-eaters’ [19, 20, 33].

The medical literature also contains a long, grim catalog of individual unsupplemented vegans, and especially breastfed infants of unsupplemented or under-supplemented vegan mothers, presenting with severe deficiency: developmental regression, brain atrophy, failure to thrive [2, 13]. These are the cases the “I feel fine” anecdote conveniently never has to meet.

Are there any reliable plant sources of B12?

There are no reliable plant sources of B12, a conclusion reached not by fiat but by decades of analytical chemistry showing that the “B12” detected in spirulina and most algae is predominantly pseudo-B12, an analogue inactive in humans [27], and that fermented foods, soil-dusted produce, and intestinal bacteria (which produce B12 in the colon, downstream of the ileal absorption site) cannot be counted on [27, 28, 33]. VeganHealth maintains an encyclopedic, referenced page testing every proposed plant source, including nori, chlorella, tempeh, duckweed, and organic produce, and the pattern is consistent: unreliable, inactive, or unproven [33].

Is B12 well-researched, or is the science thin?

This isn’t a thin literature being over-read. B12 is among the most exhaustively researched nutrients in the history of science: a century of continuous investigation, four Nobel laureates across two prizes [32], and a body of work anyone can sample by typing “cobalamin” into PubMed and watching tens of thousands of papers come back. It has its own Cochrane review [6], its own commissioned Nature Reviews Disease Primer [1], its own Institute of Medicine reference-intake process [3], and an NIH-commissioned international consensus review devoted to nothing but the fine points of measuring its biomarkers [39]. Fields this mature are not where century-long errors of the kind the interview alleges go to hide; they are precisely where such errors get found. So the claim on the table isn’t that nobody has checked whether humans need B12. It’s that almost no nutrient in history has been checked harder.

Every rung of the pyramid, one answer. This is what “settled” looks like.

Claim 2: “B12 was invented in a Merck laboratory”

Was vitamin B12 invented by a pharmaceutical company?

This confuses isolating a molecule with inventing one, and gets the history backwards.

The story doesn’t start with Merck. It starts with pernicious anemia, a disease that was, as the name records, essentially a death sentence. Patients wasted away with anemia and neurological collapse, and no treatment existed. In the 1920s, George Minot and William Murphy discovered that feeding patients large amounts of liver reversed the disease, work that (with George Whipple’s) won the 1934 Nobel Prize in Physiology or Medicine [32]. Something in liver was keeping people alive; for two decades, chemists raced to find out what.

Who actually discovered vitamin B12?

In April 1948, two teams isolated the red crystalline compound independently, publishing within a single week of each other: Rickes, Folkers, and colleagues at Merck in the United States in Science, and E. Lester Smith at Glaxo in the United Kingdom in Nature [31]. Nature’s contemporaneous editorial marveled that the twenty-two-year quest opened by Minot and Murphy was ending with single doses around 15 micrograms doing what pounds of liver had done, and within months Randolph West demonstrated that injecting just 5 to 10 micrograms of the pure substance produced a near-maximal blood-cell recovery in pernicious anemia patients [31]. Dorothy Hodgkin then solved the molecule’s structure by X-ray crystallography in 1956, among the most complex ever determined at the time, work central to her 1964 Nobel Prize in Chemistry [32].

So: a fatal disease, a liver cure, a twenty-year international hunt, two independent teams, four Nobel laureates across two prizes, and a molecule that bacteria have been synthesizing for on the order of billions of years. Merck no more invented B12 than Galileo invented the moons of Jupiter. The claim in the interview, sourced to a recent anti-B12 book, that scientists were just numbering vitamins arbitrarily (“we’ll make B1, make it 12”) isn’t an alternative history. It’s not history at all.

One final inversion worth savoring: far from being a weapon against veganism, the isolation of B12 is arguably what made lifelong veganism medically realistic, a point the vegan dietitians at VeganHealth make themselves [33]. The U.K. Vegan Society was founded in 1944; the one nutritional question hanging over the whole project was answered four years later, by the very discovery this narrative teaches vegans to resent.

Claim 3: “Deficiency symptoms are really chemical poisoning blamed on B12”

Is B12 deficiency actually chemical poisoning in disguise?

This claim has the virtue of being cleanly falsifiable, and it has been falsified about as thoroughly as anything in clinical medicine.

B12 deficiency isn’t a vague syndrome pinned on people; it has a specific, multi-marker laboratory fingerprint: low serum B12 and holotranscobalamin, elevated methylmalonic acid, elevated homocysteine, macrocytic red cells, hypersegmented neutrophils on a blood smear, and characteristic spinal-cord changes on MRI in advanced neurological cases [1, 2, 18]. No pattern of “chemical poisoning” produces that fingerprint.

And here is the decisive test: give the patient a few micrograms of cobalamin, change nothing else about their diet, environment, or “toxin exposure,” and the laboratory fingerprint reverses. The blood counts recover. MMA falls. Homocysteine falls. (Nerve damage that has gone on too long is the exception, which is why timing matters.) In the placebo-controlled toothpaste trials cited above, that biochemical reversal happens against a placebo group whose environment is identical [16, 17], and treatment trials show serum levels normalizing whether B12 is swallowed or injected [6, 7]. Pernicious anemia patients have been pulled back from the edge of death by B12 alone since 1948, exactly as liver extract did before that [31]. If the symptoms were caused by petrochemical exposure, a few micrograms of a single vitamin would not cure them. It does. Case closed, not rhetorically, but experimentally.

The interview’s related move, “people are poisoned by chemicals and the government blames a deficiency,” also has the incentive structure exactly backwards. A deficiency diagnosis leads to a pennies-per-week generic vitamin. If institutions wanted a narrative that maximized dependence and revenue, an untreatable environmental-poisoning story would serve far better than one solved by the cheapest supplement in the store.

Claim 4: “It’s the only vitamin not in plants, so it’s suspicious”

Why is B12 the one vitamin not found in plants?

The explanation is not a conspiracy. It’s microbiology, and it’s been understood for decades.

B12 is synthesized exclusively by certain bacteria and archaea [1, 27, 28]. Plants neither make it nor need it, which is why it isn’t in your fruit trees. Animals don’t make it either; they accumulate it. Ruminants like cows carry fermentation vats (rumens) full of B12-producing microbes, which need dietary cobalt to do the job. Pigs, chickens, and primates historically got theirs from soil, insects, water, and fecal contamination of food [28, 33]. Pre-industrial humans picked up traces the same unglamorous ways: unwashed produce, untreated water, and generally living in closer contact with microbial filth than any of us would now accept.

Did modern sanitation cut off our B12 supply?

Modern sanitation, meaning chlorinated water, washed produce, and food-safety standards, closed that pipeline. That trade was overwhelmingly worth it; clean water has saved more lives than any medicine. But it means that in the modern world, everyone’s B12 traces back to a managed microbial source: either bacteria cultured in fermentation tanks and put into your supplement or fortified food directly, or bacteria in and around farmed animals, increasingly propped up (as we’ll see under Claim 8) by supplements added to the animals’ feed [29, 30].

So the “suspicious” fact dissolves into an ordinary one: B12 is not an animal nutrient that vegans are missing. It is a bacterial nutrient that every animal on Earth, humans included, must obtain from microbes one way or another. Vegans simply take the direct route.

Notice that this single fact also detonates two other claims from the interview. Supplemental B12 cannot be “refined petroleum” (Claim 6 below), because it is produced by fermentation. And it requires no animal exploitation whatsoever, which will matter when we get to the ethics.

Claim 5: “Cyanocobalamin is cyanide, so they’re telling us there’s poison in it”

How much cyanide is actually in a cyanocobalamin tablet?

Time for arithmetic, which the fear-mongering never survives.

Cyanocobalamin is a large molecule with a mass of about 1,355 daltons, of which the cyanide group contributes about 26, roughly 2 percent by weight. A large 1,000-microgram tablet therefore contains about 20 micrograms of cyanide; the standard 50-microgram daily maintenance dose contains about 1 microgram. Your body routinely detoxifies cyanide via the enzyme rhodanese into thiocyanate and excretes it, and the trace amounts in everyday plant foods that contain cyanogenic compounds (flaxseed, almonds, lima beans, cassava) comfortably exceed what’s in a B12 tablet. Twenty micrograms of cyanide is, quite literally, less than you’d get from a pinch of ground flax.

Isn’t B12 used as the antidote for cyanide poisoning?

It is, and that’s the deeper irony. Cobalamin binds cyanide so avidly that a B12 form, hydroxocobalamin, is the modern hospital antidote for acute cyanide poisoning, given intravenously at five grams: five thousand times the size of a large 1,000-microgram supplement tablet. And note what that antidote reaction produces. Per the drug’s own FDA labeling, hydroxocobalamin binds cyanide to form nontoxic cyanocobalamin, which the body then simply excretes in urine. The molecule the interview frames as a poison-delivery device is, in actual emergency medicine, the safe end-product of cyanide detoxification, what your body makes cyanide into on the way out the door.

Even the interviewer, to her credit, noted mid-conversation that plant-based physicians like Dr. Michael Klaper have explained the cyanide content is far too small to matter. That’s correct. The video acknowledges the debunk and keeps the fear anyway, which tells you the fear was never really about the chemistry.

Are there people who should avoid cyanocobalamin?

Two honest nuances, because airtight means acknowledging real edge cases. In kidney failure, where clearance of cyanide metabolites is impaired, methylcobalamin or hydroxocobalamin are reasonable alternatives to high-dose cyanocobalamin, in consultation with a physician [23, 33]. And it has been speculated, though not confirmed, that heavy smokers, whose cyanide load is already elevated, might prefer non-cyano forms [35]. For everyone else, cyanocobalamin is the best-studied, most stable, cheapest form, and the NIH notes no evidence that absorption differs between forms [2, 11]. Precision is not scandal.

Claim 6: “Vitamins are refined petroleum”

Is vitamin B12 made from petroleum?

Whatever one thinks of other supplements, this is flatly, checkably false for B12, and B12 is the supplement under discussion.

Vitamin B12 cannot be practically synthesized chemically at commercial scale. Its total chemical synthesis, completed in 1972 by the collaborating teams of Robert Woodward at Harvard and Albert Eschenmoser at ETH Zürich, took almost twelve years and more than a hundred chemists (91 postdoctoral researchers and 12 doctoral students from 19 nations), and stands in chemistry lore as the monument that proved nobody would ever make B12 that way for production. Instead, all commercial B12 is produced the way nature produces it: by bacterial fermentation, using cultured microorganisms such as Propionibacterium freudenreichii, Pseudomonas denitrificans, and Ensifer adhaerens [29, 30]. European regulators’ safety dossiers for B12 describe exactly this: cyanocobalamin “produced by fermentation,” purified to better than 99 percent [30].

In other words, the one supplement the evidence says vegans need is, of all things, a purified product of bacterial culture, closer kin to the microbes in your sauerkraut than to anything from an oil refinery. The petroleum story isn’t an exaggeration of the truth. It’s the opposite of it.

Claim 7: “I’m 72 with a biological age of 22, never tested, never sick, so B12 is a scam”

This is the emotional core of the video, so let’s give it a full and fair autopsy.

Why doesn’t “I’ve been vegan 45 years and I’m fine” prove anything?

One person’s testimony cannot distinguish “B12 is unnecessary” from “this individual is lucky, unusual, or not yet symptomatic.” That’s not an insult; it’s the entire reason evidence hierarchies exist. And it comes wrapped in textbook survivorship bias: the vegans who followed this path and developed anemia, neuropathy, or worse are not hosting livestreams about their vitality. Some of them are in the case-report literature instead [2, 13, 33]. VeganHealth even maintains a page on the rare, genuinely documented long-term exception, precisely because outliers exist and precisely because outliers don’t set guidance, any more than a chain-smoking 95-year-old debunks oncology [33].

Can you really coast for decades without B12?

Recall that the liver banks a multi-year supply, recycled efficiently through bile [2]. And by his own telling, his history isn’t even 45 unsupplemented years: after his first 15 to 20 years without, he took weekly methylcobalamin for a stretch of years and tapered off only about a decade before the interview, while also spending two months every year at a health institute. A previously supplemented adult coasting on hepatic stores, roughly a decade into depletion, feeling fine? That is not a refutation of B12 science. It is a prediction of B12 science, the quiet middle of the curve, before the part nobody wants.

Can grip strength or “biological age” tests detect B12 deficiency?

No. “Never tested” is not evidence of health; it’s the absence of evidence, engineered. Balance time, push-ups, grip strength, and sit-to-stand are perfectly nice functional measures, and they measure precisely none of the things B12 deficiency degrades first. Serum B12, MMA, and homocysteine are cheap, specific, and validated [1, 2]. Refusing them while claiming certainty about what they’d show is not confidence. It’s a coin flip with the results face-down, and because B12 neuropathy can begin subtly and become irreversible without ever causing anemia [1, 2], it’s a coin flip where one side can’t be un-flipped.

What about healthy old people in Okinawa with “terrible” blood levels?

The claim arrives unsourced, and the traditional Okinawan diet includes fish and pork, so whatever it shows, it isn’t about veganism. What the actual gerontological literature shows is the opposite direction of concern: roughly one in five American adults over 60 has at least one abnormal B12 biomarker [26], deficiency in older adults runs anywhere from 3 to 43 percent depending on the definition [2], and low B12 status with elevated MMA and homocysteine tracks with worse cognitive and vascular outcomes, not secret vitality [22, 23].

None of this requires doubting that the man feels wonderful. It requires only the one thing the whole video refuses: distinguishing between feeling fine and being fine, a distinction B12, with its years-long fuse and its silent, sometimes permanent neurological endgame, was practically designed to exploit.

Claim 8: “Follow the money”

Fine. Let’s follow all of it, in three steps.

Who profits from telling vegans to take B12?

Almost nobody, which is the problem with the theory. Cyanocobalamin is off-patent, generic, and produced at industrial scale by fermentation. A full year of one common vegan regimen, a 2,000-microgram tablet once a week, costs a few dollars, less than a single trip to a juice bar. There is no moat, no monopoly, no recurring-prescription lock-in; the FDA-recognized forms are made by many competing manufacturers worldwide. If a shadowy complex needed a profit engine, it could hardly have designed a worse one than the cheapest vitamin on the shelf. Meanwhile (and this is said without malice, only symmetry) the interview itself promotes books, a paid festival, and retreat appearances. If we are auditing incentives, we audit everyone’s.

The strongest, most persistent voices telling vegans to supplement B12 are vegan institutions: the 2001 open letter signed by vegan health professionals and vegan organizations [34], VeganHealth.org (a project of the nonprofit Vegan Outreach, which explicitly declines to recommend brands) [33], the dietitians who authored the Academy’s position paper [5], and plant-based physicians such as Greger, Klaper, and Barnard, who are famously skeptical of the supplement industry in general and carve out B12 as the exception the evidence forces [35]. Their motive is transparent: every preventable deficiency case becomes an “I was vegan until it wrecked my health” story, and those stories drive people back to animal products. Vegan advocates push B12 because they are protecting vegans and veganism, not a pharma balance sheet.

How much B12 goes to animal agriculture?

Here is the fact that turns the whole conspiracy inside out. World production of the pure vitamin has grown to roughly 100 tonnes a year, and the peer-reviewed breakdown of that market puts the animal-feed sector at about 55 percent of sales, more than food and pharmaceutical uses combined [29]. European food-safety regulators maintain approval dossiers for fermentation-produced cyanocobalamin explicitly as a nutritional feed additive “for all animal species” [30]. The reason is structural. As the EU’s feed-safety panel put it, monogastric animals such as pigs and poultry “do not require cobalt but they require vitamin B12,” because their gut microbes do not make it in significant amounts [58]. Raised in confinement away from soil, insects, and manure-borne microbes, they receive it directly in their vitamin premix; the same panel notes that the B12 poultry pick up from microbial fermentation in litter is not reliable [58].

Why do farmers give cattle cobalt supplements?

Ruminants like cattle get the precursor instead, because feeding them B12 directly works poorly: in a dairy-cow study summarized by the EU feed-safety panel, only about 20 percent of supplemented cyanocobalamin made it past the rumen to the small intestine, and the panel concluded that an optimal micronutrient supply for ruminants includes cobalt [58]. Cobalt is routinely supplemented in feed and pasture so their rumen microbes can build the B12 for them, a practice dating to 1935, when mysterious fatal wasting diseases of livestock in Australia and New Zealand (“bush sickness,” “coast disease,” “enzootic marasmus”) were traced to cobalt-deficient soils and cured with trace cobalt. The same disease had baffled farmers worldwide under a dozen local names, from “cobalt pine” in Scotland to “salt sickness” in Florida. And since cobalt’s only known essential role in animals is as the center of the B12 molecule [58], ruminant cobalt deficiency simply is B12 deficiency: emaciated, dying sheep recovered dramatically on tiny oral doses of cobalt, an accidental continent-scale demonstration of this vitamin’s essentiality in mammals, run on livestock decades before anyone had a culture war to fight about it. All of this predates internet veganism by the better part of a century.

Is it true that 90 percent of B12 supplements go to livestock?

No, and it’s worth saying so plainly, because airtight cuts both ways. That figure circulates widely in vegan spaces, but it has no primary source; it appears to trace to an uncited 2013 newspaper op-ed and has been repeated ever since without one. The documented figure is the roughly 55 percent of direct B12 sales [29], plus the near-universal cobalt supplementation of ruminants, which doesn’t show up in B12 sales statistics at all. “A majority, plus the cobalt pipeline” is the defensible claim, and it is entirely sufficient.

Because look at what it means. If B12 were an invention designed to smear veganism as deficient, the conspirators forgot to tell the meat industry, which quietly operates the largest B12 supplementation program on the planet just to keep its products B12-positive. For the typical modern omnivore, meat is a B12 supplement with extra steps and a middleman with a heartbeat. Vegans who take the tablet aren’t falling for the system. They’re skipping it.

“Nobody in the Zen monastery took supplements”: the naturalism trap

Can a natural diet require supplements?

The interview leans repeatedly on an appeal to nature: a divine universe wouldn’t require pills; monks never supplemented; our bodies recycle what they need if our consciousness is right.

But “natural” is a description, not a credential. The natural human condition also featured child mortality near half, endemic intestinal parasites, and pernicious anemia as an untreatable death sentence [31, 32]. Our ancestors’ B12 pipeline was environmental grime (untreated water, unwashed roots, microbial contamination), an unreliable source even then, and one that modern sanitation has rightly closed [28, 33]. VeganHealth addresses this squarely in an essay titled “Can a Natural Diet Require Supplements?”: the question isn’t whether supplementation is natural, it’s whether the nutrient is necessary, and it is [33].

Nor is B12 unique in this. Modern omnivorous life is quietly fortified everywhere you look: iodine in salt (ending endemic goiter), vitamin D in milk (ending rickets), folic acid in flour (preventing neural-tube defects), and B12 itself in the feed of the animals people eat [29, 30]. Nobody argues that iodized salt disproves the human diet. A vegan taking a weekly chewable is doing exactly what the whole modern food system already does, just honestly, and without the animal.

Can gut bacteria make enough B12 for us?

They genuinely do make B12, but in the colon, downstream of the ileum where B12 is absorbed. It leaves the body unused [33]. This isn’t a hypothesis; it’s anatomy, and it was tested directly in the raw-vegan study described below, where probiotic supplements failed to fix B12 status while tablets and fortified yeast succeeded [15].

B12 deficiency is not a “vegan disease”: the omnivore numbers

How common is B12 deficiency in meat eaters?

Here is the part that dissolves the “B12 exposes veganism’s weakness” framing entirely, because deficiency is common among people who eat meat every day.

Per the NIH’s summary of national survey data (NHANES 2007–2018), about 3.6 percent of all U.S. adults are outright B12 deficient and about 12.5 percent are insufficient. In a population where vegans are a small minority, that means the overwhelming majority of those deficient Americans are omnivores [2, 25]. Raise the cutoff to the level many clinicians treat as the gray zone and, in earlier NHANES data, 26 percent of adults fell below it [2]. Authoritative reviews put low or marginal B12 status at up to 40 percent of Western populations [1, 2]. Among older adults it’s worse: depending on the definition, 3 to 43 percent of community-dwelling seniors are deficient, roughly one in five Americans over 60 has at least one abnormal B12 biomarker [26], and atrophic gastritis, which cripples absorption of food-bound B12 specifically, affects 8 to 9 percent of people over 65 [2].

Why does the government tell everyone over 50 to take B12?

Because of that last mechanism. Since 1998, the Institute of Medicine has advised that everyone over 50, steak lovers included, get most of their B12 from fortified foods or supplements, because the crystalline form absorbs even when food-bound B12 no longer does [2, 3]. Read that again: mainstream nutrition policy tells half the adult lifespan of omnivores to do exactly what vegans are told to do. If needing supplemental B12 “disproves” a diet, it disproves being over fifty.

The pattern holds all the way down. Pernicious anemia, an autoimmune malabsorption disease with nothing to do with diet, remains the most common cause of clinically evident B12 deficiency in the world [2]. Metformin, a widely used diabetes drug, can deplete B12 [2, 56], and long-term use of acid-blocking drugs has been linked to lower B12 as well, though those studies are inconsistent, which is why monitoring is recommended for people on prolonged treatment [2, 56].

Does eating meat actually protect against B12 deficiency?

Less than you’d think. In the Framingham Offspring cohort of 2,999 ordinary, overwhelmingly omnivorous Americans, 39 percent had plasma B12 below 258 pmol/L, 17 percent below 185, and 9 percent below 148, with little difference between age groups [24]. Deficiency prevalence was roughly half as high among regular fortified-cereal eaters as among those who ate none (12 versus 23 percent), and similarly split between the highest and lowest dairy consumers (13 versus 24 percent), but showed no significant differences across meat-intake tertiles [24]. The authors’ conclusion was that supplements, fortified cereal, and milk appear protective against low B12. Eating animals every day did not protect these people; the fortification infrastructure did.

Is B12 insufficiency common in pregnancy, even for meat eaters?

Yes, and this is where the “vegan problem” framing falls apart most completely, because the stakes are highest exactly where the diet matters least. A 2016 systematic review and meta-analysis by Sukumar and colleagues, pooling dozens of studies, found vitamin B12 insufficiency in roughly one in five pregnant women in the first trimester (21 percent), 19 percent in the second, and 29 percent by the third [51]. The authors stated it plainly: B12 insufficiency during pregnancy “is common even in nonvegetarian populations,” and B12 levels fall as pregnancy progresses [51]. (In fairness, the same review found no consistent link between that insufficiency and low birth weight, so this is about maternal status, not a proven birth-weight harm.) The lesson isn’t that vegan pregnancy is uniquely risky. It’s that pregnancy raises B12 demand for everyone [56], which is why a reliable source matters for every pregnant woman, and simply matters most for one following a plant-based diet.

So the honest picture is this: B12 adequacy in the modern world is a human engineering problem, solved for everyone, omnivores very much included, by fortification and supplementation running quietly in the background. Vegans aren’t the exception to the system. They’re just the ones who can see it.

What actually happens to vegans who don’t supplement

What percentage of vegans are B12 deficient?

Since the video’s thesis stands on one unsupplemented vegan feeling great, it’s worth stating what the record shows about unsupplemented vegans as a group.

The earliest cohort data, a 1955 study of British vegans, already documented overt deficiency, including nerve damage and dementia, in the pre-supplement era [33]. Modern systematic reviews of serum B12 in vegetarians and vegans find high deficiency prevalence in every age group among those without a reliable source, ranging in some studied groups to a large majority [19, 20]. The single most cited snapshot comes from the EPIC-Oxford cohort: among 689 British men, 52 percent of vegans were vitamin B12 deficient (below 118 pmol/L), versus 7 percent of vegetarians and exactly one of 226 omnivores. Tellingly, serum levels showed no association with years on the diet, consistent with stores depleting silently on their own schedule [37].

Do raw vegans get enough B12 from fermented foods?

No. A two-year Finnish study of raw “living food” vegans, whose participants ate roughly two kilograms of fermented foods a day on the theory that fermentation and friendly gut bacteria would supply their B12, watched status deteriorate slowly but consistently in six of the nine followed [33, 38]. Studies of non-supplementing vegans consistently show elevated homocysteine, the stroke- and dementia-associated metabolite, where supplementing vegans show healthy levels [22, 23, 33].

Two studies deserve special attention from the whole-food and raw-food community the video was addressing, because both groups ate the kind of whole-food diet the video champions: mostly raw in one, unprocessed fruit, grains, legumes, greens, and nuts in the other. Donaldson studied 49 followers of a mostly raw vegan diet (the Hallelujah Acres program, mostly two to four years in) and found 76 percent with serum B12 below 300 pg/mL. In follow-up, sublingual B12 tablets and fortified nutritional yeast corrected the elevated methylmalonic acid, while probiotic supplements did not [15], simultaneously demonstrating the fix and closing the “my gut bacteria will handle it” exit. And Crane and colleagues found that 47 of 78 vegan adults who had gone at least a year without B12 supplements or fortified foods had serum B12 below 200 pg/mL; in the same report, chewed tablets worked far better than slow-dissolving tablets swallowed whole, a finding covered in the protocol below [14].

What happens to babies of B12-deficient vegan mothers?

At the bottom of this literature sit the cases that should end the debate for anyone with a conscience: severely deficient breastfed infants of vegan mothers, including a mother who believed she was covered because she took a multivitamin containing B12 [13]. Infant B12 deficiency can cause developmental regression, failure to thrive, and even measurable brain atrophy [2, 13, 49, 50]. There is a genuinely hopeful wrinkle here, and it’s worth stating precisely: in case reports, that cerebral atrophy has substantially reversed on brain imaging after B12 treatment [49, 50]. But imaging reversal is not the same as full recovery. The same case literature, and authoritative reviews, warn that long-term cognitive, motor, and language deficits often persist, and that outcome depends heavily on how early treatment begins [1, 49]. Which is exactly the point: caught early, much can be undone; caught late, the damage can be permanent. These children did not choose a philosophy. They inherited an information environment, the very one videos like this pollute.

People really do differ: the heterogeneity question, taken seriously

The most sophisticated version of the anti-supplement argument isn’t “B12 is fake.” It’s “people vary, so maybe some of us absorb better, recycle better, or host bacteria that cover us.” That question deserves a straight answer, because the variation is real, measured, and, properly understood, cuts the opposite way from how it’s used.

Is there a gene that affects B12 levels?

Yes, several. Genome-wide association studies have mapped common variants that shift B12 status. The strongest hit is FUT2, the classic “secretor” gene: people homozygous for the non-secretor variant run roughly 10 to 25 percent higher total serum B12, a finding replicated across European, Chinese, and Indian populations, with further loci identified in TCN1, CUBN, and MUT [40]. There is now an entire curated database of B12-associated genomic variants [41].

Two things follow. First, an amusing nuance: when researchers split serum B12 into its two carrier fractions, the famous FUT2 effect ran through holo-haptocorrin, the biologically inert fraction, while the bioactive holotranscobalamin was untouched [48]. The best-known “B12 gene” mostly moves the part of the number that doesn’t feed your cells. Second, genetic variation also runs in the unlucky direction: mutations in the intrinsic-factor gene (GIF) and in CUBN (Imerslund–Gräsbeck syndrome) cause deficiency in people eating meat at every meal [40]. Heterogeneity is not a one-way ticket to safety.

Can some people just absorb or recycle B12 better?

In rate, yes; in direction, no. Intrinsic factor capacity spans a spectrum, from normal abundance through age-related atrophic gastritis down to pernicious anemia’s total loss [1, 2]. Fractional absorption genuinely adapts: at tiny intakes the intrinsic-factor system captures around half of what passes through, versus roughly one percent of a large dose [2, 10]. That is efficient, but efficiency cannot conjure micrograms that were never swallowed. And enterohepatic recycling, meaning reclaiming the B12 your bile secretes, differs between people; classic work by Victor Herbert estimated that a highly efficient recycler with full stores could take on the order of decades to run dry, versus a few years for someone who recycles poorly [33, 44]. This is the honest explanation for the rare, genuinely documented long-term unsupplemented exception [33], and, notably, for the interview’s own protagonist. Variance in the speed of depletion is fully compatible with, indeed predicted by, everything in this article. What it does not do is reverse the arrow.

Do Indian vegetarians prove humans can adapt to make their own B12?

The best card in this deck is a real Nature paper: in 1980, Albert, Mathan, and Baker showed that Pseudomonas and Klebsiella cultured from the small intestines of healthy southern Indian subjects could synthesize assay-active B12 in vitro, and proposed this might explain why some Indian vegetarians resisted overt deficiency [42]. Cited fairly, it’s intriguing. Read fully, it dissolves. The finding was test-tube synthesis by organisms from people carrying heavy small-bowel colonization, itself a product of high-microbial-exposure environments, not something a sanitized Westerner can will into existence.

The modern microbiome literature then delivers the twist: people with heavy small-intestinal bacterial loads tend to have lower B12 status, because bacteria bind cobalamin with an affinity rivaling intrinsic factor’s, and the great majority of gut microbial species consume corrinoids rather than donate them [43]. That’s why small intestinal bacterial overgrowth is a recognized cause of B12 deficiency [2, 43]: when microbes do live upstream of your absorption site, they mostly steal. And the population-level check is brutal for the adaptation story. Indian lacto-vegetarian populations, the very groups the hypothesis was built around, show some of the highest measured rates of B12 deficiency and elevated homocysteine in the world [33, 45]; in the 2026 MATCOBIND trial, 53.8 percent of the predominantly vegetarian pregnant women enrolled in India and Nepal were already B12-deficient in the first trimester [62]. As for the colon, where our resident bacteria really do make B12, it sits downstream of the ileal receptors, and while researchers have recently probed possible trace colonic absorption with isotope-labeled B12, nothing found changes the bottom line: no non-supplementing vegan population anywhere has been shown to maintain adequate status from internal synthesis [33]. There is no documented route by which colonic B12 meaningfully “finds its way up.”

What does all this variation mean for me personally?

It explains the variance: why one unsupplemented vegan crashes in two years and another coasts for twenty, why exceptions exist, why your friend’s anecdote and the case reports can both be true. But you cannot feel your FUT2 genotype, your intrinsic-factor output, or your biliary recycling efficiency from the inside. The only way to know which end of the distribution you occupy is the blood panel. That converts heterogeneity from an argument against supplementing into the strongest possible argument for testing: if you sincerely believe you’re the exception, the scientific response is a serum B12 and MMA test, not a vow of confidence. And the cost asymmetry does the rest of the work. Being wrong about needing a supplement costs pennies; being wrong about being special can cost your spinal cord.

The strongest counter-evidence on record: an honest audit

Is there any study showing humans don’t need B12?

A document that intends to be airtight has to do the thing its opponents never do: go looking for the best evidence against its position and print what it finds. So, how would one assess the contrary literature? Search the systematic reviews, the Cochrane library, and the position statements of every nutrition body on Earth for any conclusion that humans don’t need B12, that deficiency isn’t a real clinical entity, or that vegans can safely skip a reliable source. The result of that search is: nothing. No such review exists. No such trial exists. No retraction, no replication crisis, no dissenting expert body. Recent regulatory movement has gone the other direction, with the German-speaking nutrition societies raising their reference intake in 2019 [4]. The essentiality of B12 has the same evidentiary status as the essentiality of iron.

What does exist, meaning the studies that genuinely show “conflicting results” and that a sharp critic could wave, falls into three clusters, each of which turns out to be about a different question. Here they are, at full strength.

Why did the big B-vitamin heart trials fail?

Through the 2000s, a series of large RCTs (HOPE-2, NORVIT, SEARCH, VITATOPS and others) gave B vitamins to tens of thousands of mostly B12-replete cardiovascular patients. Homocysteine fell on schedule; heart attacks mostly didn’t [22]. These null results are real, and they killed the strong version of the homocysteine-CVD hypothesis, though the meta-analytic picture retains a modest stroke reduction, clearest in low-folate populations [22]. But notice what these trials tested: whether lowering homocysteine in non-deficient people prevents cardiovascular events. That is not the question “do humans need B12,” any more than a failed trial of extra water for marathon performance would show hydration is a myth. Not one of these trials enrolled deficient people and asked whether repletion fixes deficiency, the question that was settled in 1948 and re-confirmed by repletion trials ever since, including placebo-controlled ones [6, 7, 16, 17].

Is it true that a trial found B12 caused harm?

Yes, in one specific population, and it’s worth knowing exactly what it showed. The single most legitimate “B12 caused harm” result in the literature is the DIVINe randomized trial: 238 patients with diabetic kidney disease given high-dose B vitamins (folic acid 2.5 mg, B6 25 mg, and a full 1,000 mcg of cyanocobalamin daily) or placebo for three years. The vitamin group’s kidney function declined faster (a GFR drop of 16.5 versus 10.7) and vascular events roughly doubled, with the harm concentrated in participants whose kidney function was already below half of normal [46]. This is a real randomized finding and this article does not shrink from it. It is precisely why the dosing guidance in the protocol below routes people with kidney disease away from high-dose cyanocobalamin and toward methyl- or hydroxocobalamin under a physician’s care [23, 46], the same conclusion drawn by the trial’s own investigators [23]. But look at what DIVINe is and isn’t: megadoses, in renal failure, of the one form whose cyanide-handling requires working kidneys. It is a boundary-condition finding about form and dose in a sick subgroup, and the fact that an RCT found that boundary and the guidance absorbed it is the system functioning, not the edifice cracking. Nobody in DIVINe was deficient; nothing in DIVINe suggests deficiency is fictional.

Does B12 cause lung cancer?

The study anti-supplement critics cite most is Brasky and colleagues’ 2017 analysis of the VITAL cohort (77,118 people, 808 lung cancers), which found that men, not women, taking high-dose individual B12 supplements (over 55 mcg per day averaged across a decade, and not multivitamins) had roughly double the lung-cancer risk, with the association concentrated in smokers and absent for adenocarcinoma, the subtype least tied to smoking [47]. The authors themselves called it a concern worthy of further evaluation rather than proof, and published critiques note the self-reported exposure, the inability to exclude confounding by smoking intensity, and contradicting studies, including meta-analytic evidence pointing the protective direction for B6 [47]. Set against it stands the randomized evidence: a meta-analysis of 18 RCTs in nearly 75,000 people found B-vitamin supplementation, including B12 up to 2,000 mcg daily, had little or no effect on cancer incidence, cancer death, or total mortality [2]. The practical residue of this cluster is modest and reasonable: don’t megadose recreationally, and if you smoke, the most important B12-related intervention available to you is quitting. What the cluster cannot carry is the load the anti-B12 narrative piles on it, since a study premised on B12’s biological potency cannot double as evidence that B12 is inert or unnecessary.

And that is the pattern across all three clusters, which is worth stating plainly because it is the answer to “are there studies that make this questionable.” Every genuinely rigorous “contrary” result in the record concerns supplementing already-replete people for chronic-disease prevention, or form and dose in special populations. None concerns whether B12 is essential, whether deficiency is real, or whether vegans need a source. The anti-B12 position has no cluster of its own; its citations are books, podcasts, and testimony. Meanwhile, examining the opposition’s best evidence didn’t weaken this article’s recommendations, it sharpened them, adding the kidney caveat and the no-megadosing note. An argument that improves when fed its strongest opposition is the kind you can freeze.

The single most harmful sentence in the video

Should vegans buy unfortified nutritional yeast?

Absolutely not, and among everything said in the interview, this piece of practical advice stands out as uniquely damaging: not merely declining supplements, but deliberately buying unfortified nutritional yeast to avoid the B12 added to foods.

Understand what this means. Nutritional yeast contains no B12 of its own. Saccharomyces cerevisiae is a fungus and cannot synthesize cobalamin; only fortified brands contain it, which is why labels must be checked [2, 33]. Fortified foods are the quiet safety net that partially protects many vegans who never think about B12 at all. The video’s advice cuts that net on purpose, and because of the multi-year storage buffer, its casualties won’t surface until long after the livestream is forgotten, when the connection will be invisible to everyone, including the victims. Some of those victims, statistically, will be children and breastfed infants. There is no charitable reading of health advice whose harm is engineered, by biochemistry rather than intent, to arrive anonymously and years late.

Do kombucha, algae, or other “natural” B12 sources work?

A small real-world snapshot shows where this road leads. A 2021 study from Romania collected recent lab results and supplement habits from 42 vegans. The seven who relied on products they believed were “natural” B12 sources (algae, kombucha, borscht, and yeast) all had active B12, measured as holotranscobalamin, below the 35 pmol/L level the labs used to flag depleting stores, with a median of 29 [57]. None of the 42 regularly ate B12-fortified foods; the authors attributed that partly to poor availability in Romanian stores and partly to an unjustified fear of “artificial” vitamins in processed food [57]. The group was tiny and the study observational, so treat it as an illustration rather than proof, but it is exactly the pattern the biochemistry predicts.

So what should you actually do? The airtight protocol

Everything below draws on the NIH [2], the Cochrane evidence on oral therapy [6], VeganHealth’s dietitian-authored guidelines [33], Dr. Greger’s regimen from his B12 video series [35], and the randomized trials cited along the way. Where those sources differ, the text says so. It is boring, cheap, and it works.

How do I fix a B12 deficiency?

If you’ve had no reliable B12 source for more than a few months, replenish first: VeganHealth suggests 2,000 mcg once daily for two weeks to refill stores [33]. If you’ve been formally diagnosed as deficient, the treatment literature uses 1,000 mcg per day for one to four months depending on how low you started, before dropping to maintenance [35]. High-dose oral therapy corrects deficiency about as well as injections for most people, a finding once called one of medicine’s best-kept secrets [8]. In a landmark randomized trial, 2,000 mcg taken by mouth daily produced higher serum B12 than monthly injections [6, 7]. A 2018 Cochrane review of three randomized trials, with 153 participants in total, concluded that oral and injected B12 have similar effects on normalizing serum levels and that oral treatment costs less, while rating that evidence low quality because the trials were few and small [6]; subsequent clinical commentary agrees [9]. The reason it works: free B12 is absorbed two ways, actively with intrinsic factor and passively without it, and passive diffusion takes up roughly 1 percent of a large dose even when intrinsic factor is missing [2, 6, 10, 56].

How much B12 should a vegan take per day?

Maintenance dosing by situation, using cyanocobalamin unless noted:

• Adults (roughly 18–65): 50 mcg once daily, or 2,000 mcg once weekly [35]; VeganHealth’s weekly option is 2,500 mcg [60]. For pregnancy and breastfeeding, see below.
• Older adults (65+): higher daily dosing. VeganHealth suggests 500 mcg per day, and Greger’s updated chart uses 1,000 mcg per day [33, 35]. This is evidence-based, not arbitrary: see the trials below.
• Babies and toddlers (about 6 months, once solids begin, to 3 years): 5 mcg per day [21]
• Children 4 to 10: 25 mcg per day, roughly half the adult dose [21]
• Children 11 and up: adult dosing, 50 mcg per day or 2,000 mcg per week [21]
• Pregnancy and breastfeeding: 250 mcg per day is now the best-supported dose. In a 2026 double-blind randomized trial of 708 predominantly vegetarian pregnant women in India and Nepal, 250 mcg of methylcobalamin a day, taken from the first trimester to six months after birth, left fewer mothers B12-deficient by the third trimester than 50 mcg a day (16 versus 23 percent) and gave their infants slightly higher mental development scores at 9 to 12 months, about 2 points, with no difference in motor scores [62]. The caveats: the women were predominantly vegetarian rather than specifically vegan, the trial used methylcobalamin, a quarter of participants were lost to follow-up, and the mental-score benefit was clear at the Indian site but not statistically significant at the Nepali one [62]. Earlier guidance lists 50 mcg per day, ideally split into two half-doses, or 2,000 mcg per week [21, 35]; VeganHealth recommends daily rather than weekly dosing during pregnancy and breastfeeding, citing too little research on non-daily regimens [60]. Get B12 status checked through the pregnancy [21, 35].
• Kidney disease: avoid high-dose cyanocobalamin, and discuss methylcobalamin (typically 1,000–2,000 mcg per day) with your physician [23, 33, 46]

Why do people over 65 need such a high dose?

Because absorption declines with age, and the dose needed to actually normalize the biochemistry turns out to be far higher than most supplements provide. Two trials pin this down. In a dose-finding study of older adults, researchers tested 25, 100, and 1,000 mcg per day: the 25 and 100 mcg doses lowered but did not normalize methylmalonic acid in most participants, and only the 1,000 mcg dose reliably brought it into the normal range [52]. A second, larger randomized trial in older people with mild deficiency tested doses from 2.5 up to 1,000 mcg and found that 647 to 1,032 mcg per day produced 80 to 90 percent of the maximum achievable reduction in methylmalonic acid [53]. That’s the evidence behind the higher daily doses after 65, and behind Dr. Greger’s 1,000 mcg a day: not a guess, but what the trials show it takes to normalize the biochemistry. Those trials enrolled older people who were already mildly deficient, though, and VeganHealth notes there’s no evidence that pushing methylmalonic acid below the normal range for one’s age brings any extra cognitive benefit [60], which helps explain why recommendations for this age group range from 500 to 1,000 mcg a day.

Why are supplement doses so much higher than the RDA?

Because intrinsic factor, the transport protein that handles efficient absorption, saturates at about 1 to 2 mcg per sitting and needs roughly 4 to 6 hours to reset [2, 33, 56]. You can watch the saturation happen: one study, as reported in O’Leary and Samman’s review, found that about 50 percent of a 1 mcg dose was retained, but only 20 percent of a 5 mcg dose and 5 percent of a 25 mcg dose [56]. Infrequent large doses therefore work mostly through the roughly 1 percent passive-diffusion route (absorption is about 2 percent at 500 mcg and 1.3 percent at 1,000 mcg [2, 10]), so the math demands more, less often. As VeganHealth explains, that passive route is exactly why vegans can take B12 once a day, or even once a week, by taking larger doses than food would ever supply [60].

Does stomach acid destroy B12 supplements?

No. It’s closer to the opposite: stomach acid is part of how you get B12 out of food. In food, B12 is bound to protein, and stomach acid is what cleaves it free. The freed B12 then rides a carrier protein (haptocorrin, also called R protein) into the small intestine, transfers to intrinsic factor there, and is absorbed at the end of the small intestine [56]. The common problem is too little acid, not too much. Age-related gastritis reduces or eliminates the acid needed to free B12 from food protein, while the B12 in supplements and fortified foods isn’t protein bound, so it stays available [56]. That is the logic behind the advice that adults over 50 get most of their B12 from fortified foods or supplements [2, 3, 56].

Should I take B12 on an empty stomach?

For large doses, it helps a little; for the doses recommended here, it doesn’t matter. VeganHealth, summarizing the absorption research, reports that taking a supplement with food reduces passive absorption by about 40 percent, so doses above roughly 400 mcg are best taken on an empty stomach if you want to absorb the most, while for smaller doses food may even help [60]. Its recommended doses are calculated to be sufficient either way [60], and the trials bear that out: in the two randomized trials described below, one group dosed before breakfast and the other with breakfast, and both worked [61, 63]. Take your B12 whenever you’ll reliably remember it.

Is 2,000 mcg of B12 once a week enough?

For most healthy adults, yes. The trick is that the RDA is really a target for how much you absorb. VeganHealth spells it out: the U.S. RDA assumes about 1.2 mcg absorbed per day, or 8.4 mcg per week, while matching Europe’s higher intake target works out to about 14.9 mcg absorbed per week [60]. A large tablet delivers a week’s worth of absorption in one sitting through the passive route. Dr. Greger’s weekly maintenance figure is 2,000 mcg [35]. VeganHealth’s weekly option, built to the higher European target, is 2,500 mcg, and its own example is five 500 mcg tablets taken together [60]. So if your bottle says 2,000 or 2,500, either is reasonable; the 2,500 simply builds in more margin.

Is taking B12 daily better than once a week?

For healthy adults, the best randomized evidence says weekly works. In a 12-week randomized, double-blind trial, 36 vegans and vegetarians with marginal deficiency took either 50 mcg of cyanocobalamin daily or 2,000 mcg once a week (with placebo tablets on the other six days). Both doses raised active B12 and lowered methylmalonic acid and homocysteine, with no difference between the groups on those markers, and the weekly group actually ended with higher total serum B12 [61]. The authors still favored the low daily dose as sufficient [61]. (The trial was partly funded by a company, Phoenix Srl, which the authors state had no role in the study [61].) An observational study pointed the other way, finding higher active B12 among Romanian vegans who dosed more often [57], but observational data rank below a randomized trial. Two situations still call for daily dosing. VeganHealth recommends daily rather than weekly B12 during pregnancy and breastfeeding, given how little research exists on non-daily regimens at a time when the stakes for the baby are high [60]. And in older adults, a Spanish trial described by VeganHealth found that after eight weeks of 1,000 mcg daily, switching to 1,000 mcg once a week kept serum B12 above 156 pmol/L in only 74 percent of participants [60], which fits the daily dosing advised for people over 65 above.

Can I get enough B12 from fortified foods instead?

Yes, with attention to timing. Small fortified doses ride the intrinsic-factor system, so they must be spread across at least three servings a day, spaced 4–6 hours apart, together supplying roughly double the daily value. Greger’s rule of thumb is about 190 percent of the DV across three servings [35]. Fortified nutritional yeast is the classic vehicle, and these serving sizes meet the target for several common brands [35]:

• Lotus (Australia and New Zealand): 1 tsp, three times daily
• Marigold Engevita (UK): 2 tsp, three times daily
• Anthony’s Premium (Canada): 1 tsp, three times daily
• Hoosier Hill Farm (Canada): 1 tsp, three times daily

Always check the label, because fortified is the operative word, and store B12 foods and supplements away from light, which degrades cobalamin [33].

Cyanocobalamin or methylcobalamin: which is better?

Cyanocobalamin is the safest default. It is the most stable form, the form behind virtually the entire treatment-trial literature, and the NIH notes no evidence that absorption differs between forms [2]. The “coenzyme” forms marketed as premium, methylcobalamin and adenosylcobalamin, are not likely to be superior [11], for a simple reason: supplement B12 is stripped of its side group after absorption and rebuilt by your cells into whichever active form they need, so your body makes its own methylcobalamin from either starting point [2, 11, 57, 59]. VeganHealth’s verdict is blunt: the hype around the other forms is “mostly propaganda from the supplement industry” [33], a delicious irony given which side of this debate cries “follow the money.”

That said, methylcobalamin is not a failure, and it’s worth getting the evidence right in both directions. The best head-to-head comparison in vegans is small and observational: among 35 Romanian vegans who had supplemented for at least a year, the 21 using cyanocobalamin had a median active B12 (holotranscobalamin) of 150 pmol/L, versus 78.5 for the 14 using methylcobalamin, and the gap held after the authors adjusted for dose, dosing frequency, supplement form, and how long people had been vegan and supplementing [57]. Yet 78.5 is still in the healthy range, as VeganHealth points out, and the methylcobalamin users tended to dose less often [57, 59]. More encouraging for methyl, a 2026 double-blind randomized trial (MATCOBIND) gave predominantly vegetarian pregnant women in India and Nepal either 50 or 250 mcg of methylcobalamin daily, and among the 531 who completed it, active B12 rose in both groups [62]. VeganHealth now considers 50 mcg a day of stand-alone methylcobalamin likely adequate for most people, while noting that methylmalonic acid wasn’t measured [59]. The higher dose did better, though, which matters for pregnancy (see the dosing list above) [62]. The often-repeated claim that methylcobalamin “failed” in vegans even at high doses traces to three people in Donaldson’s raw-vegan study: after three weeks on 1,000 to 2,000 mcg a day, two normalized their urinary methylmalonic acid and the third sat just above the cutoff (4.1, against a normal of under 4.0), as VeganHealth details it [15, 35, 59].

The practical difference is stability. Methylcobalamin breaks down under light [35, 57], and in a lab stability study described by VeganHealth it degraded heavily when mixed with vitamin C, thiamin, or niacin, and in acidic conditions like those in some gummies and chewables [59]. So choose cyanocobalamin when you can. If methylcobalamin is what you have, take it daily as a stand-alone supplement, store it away from light, and don’t count on it inside a multivitamin. The exceptions run the other way: people with kidney disease should avoid high-dose cyanocobalamin, and methylcobalamin is a reasonable alternative for them [23, 33, 35]; it has also been speculated, though not confirmed, that heavy smokers might do better with non-cyano forms [35].

Are B12 liquid drops or 5,000 mcg doses better?

Not for routine maintenance. Once you’re above what you need, bigger isn’t meaningfully better: only a small fraction of a megadose is absorbed, and B12 beyond what the blood’s carrier proteins can hold is excreted in urine [56]. No upper intake limit has been set [2, 3], but VeganHealth, while calling the cutoff somewhat arbitrary, advises against taking more than 1,000 mcg a day long term without a physician’s guidance [60], and the one observational cancer signal involved long-term, high-dose supplement use [47]. A 5,000 mcg product can still be useful: taken once a week, it covers a weekly regimen with room to spare. As for liquids, the Romanian study saw the highest active B12 among people using liquid forms, then chewable or sublingual tablets, with swallowed tablets lowest, but only five people used drops, far too few to conclude much [57]. A liquid methylcobalamin also stacks the two weak points described above: a light-sensitive form in a bottle you open every day [57, 59]. Whatever form you choose, store B12 in a dark, cool place [33].

Is sublingual or chewable B12 better than swallowing it?

For a tablet that dissolves properly, probably not. In a small randomized trial of 30 people with low B12, about half of them vegetarians, 500 mcg a day taken under the tongue, 500 mcg swallowed, and a swallowed B-complex tablet all raised serum B12 equally, from roughly 100 to roughly 290 pmol/L within four weeks [63]. Dissolving does seem to matter, though. In a small comparison within Crane and colleagues’ study of vegans, seven people who chewed a 100 mcg tablet once a week for six weeks raised their serum B12 from an average of 116 to 291 pg/mL, while nine who gulped the same tablets whole barely moved, from 123 to 138 [14]. That batch of tablets dissolved slowly, with about a tenth still undissolved after ten minutes in water or acid, and the authors concluded that serum B12 rose “only if the tablet could be readily dissolved” [14]. They also doubted that any absorption happened in the mouth itself [14]. Your saliva does contain haptocorrin, a B12-binding protein that escorts the vitamin through digestion [2], VeganHealth recommends chewing B12-only supplements [33], and the Romanian observational data lean the same way [57]. The sensible approach: chew your tablet or let it dissolve, since it costs nothing and protects you against a slow-dissolving pill, but don’t pay extra for a “sublingual” label. The dose and the habit matter more than the route.

Is a multivitamin enough for B12?

Not as your sole source. In a laboratory study, Kondo and colleagues dissolved three popular multivitamin-mineral pills in water at body temperature and found 20 to 90 percent of the B12 present as analogues after two hours; the conversion was driven by vitamin C, thiamine, and copper acting together, and the same multivitamins without minerals did not produce it [12]. In mice, some of those analogues failed to activate, or partly inhibited, a B12-dependent enzyme, though the authors cautioned against extrapolating from animals to humans [12]. Consistent with that mechanism, the B-complex tablet in the sublingual trial above, which contained thiamine and vitamin B6 but no vitamin C or copper, worked as well as plain B12 [63]. The tragic infant case above involved a mother relying on a multivitamin [13]. Methylcobalamin is especially vulnerable in mixed formulas, as noted above [59]. A standalone B12 supplement, ideally chewed or allowed to dissolve, is the reliable tool [33, 35]. (If you do take a multivitamin for other reasons, swallow it whole rather than chewing [33].)

Does B12 toothpaste work?

Partially. Two double-blind, randomized, placebo-controlled trials found a B12-fortified toothpaste, used two minutes twice daily, improved B12 status on average in vegans [16] and in older adults [17], which is a lovely stand-alone demonstration that adding B12 and nothing else fixes the markers. But it didn’t work in every individual, so it belongs as an adjunct verified by testing rather than a primary strategy [35].

How do I get my B12 tested?

The workup is simple: serum B12, confirmed with methylmalonic acid (the most specific marker) when serum values are borderline, with homocysteine as supporting evidence [1, 2, 33]. Skip spirulina and chlorella in the weeks before testing, since their pseudo-B12 analogues can inflate a serum reading while doing nothing for you [27, 33]. If you’ve gone years unsupplemented, test now: caught early, deficiency is usually fully and cheaply reversible; caught late, the neurological component may not be [1, 2].

Can you take too much B12?

The Institute of Medicine set no upper intake limit for B12 because of its low toxicity [2, 3]. The notable minor side effect is acne-like breakouts in a small number of people at high doses, which resolve on dose reduction [33]. One last preemption, since it’s the objection most likely to be thrown at this post: headlines linking high blood B12 to cancer come from observational studies of serum levels, which disease itself can elevate, since some illnesses raise the body’s B12-binding proteins independent of intake [33]. The controlled evidence points the other way: a meta-analysis of 18 randomized trials in nearly 75,000 people found B-vitamin supplementation, including B12 at doses up to 2,000 mcg per day, had little or no effect on cancer incidence, cancer deaths, or total mortality [2]. (The VITAL cohort finding on high-dose supplements in male smokers is examined in full in the audit section above [47].)

Don’t some expert bodies advise against vegan diets for kids and pregnancy?

They do, and it’s worth engaging honestly, because a critic will raise it and the resolution actually strengthens the case rather than weakening it. In 2016 the U.S. Academy of Nutrition and Dietetics judged well-planned vegan diets appropriate for all life stages [5], while the German Nutrition Society (DGE) declined to recommend a vegan diet for pregnant women, nursing mothers, infants, children, or adolescents, specifically because it requires supplementation [55]. A French-speaking pediatric group took a similar cautious line, stressing that on a vegan diet “vitamin B12 and vitamin D supplementation is always necessary” [54].

Two things resolve the apparent conflict. First, the disagreement isn’t about the biology. Every one of these bodies agrees on the underlying facts: an unsupplemented plant-based diet is inadvisable in pregnancy and childhood, and B12 must be supplied. The dispute is narrower and more political, about whether to affirmatively recommend a diet that depends on a supplement to vulnerable groups, not about whether the diet can be made adequate. That is exactly what “well-planned” is doing in the Academy’s phrasing. As one review reconciling the positions put it, everyone agrees the supplement is non-negotiable; they differ only on default messaging [55].

Second, the most-cited dissent has since softened. The DGE revised its position in 2024: rather than advising against vegan diets for these groups, it now states it “cannot make a clear recommendation either in favour of or against a vegan diet” for them, citing limited data and the need for well-informed planning and supplementation [55]. So the strongest version of the “even the experts say no” objection is already out of date. The trajectory of expert opinion is toward the position this article takes: a well-planned, supplemented vegan diet can work at every life stage, and the supplement is the plan working, not the plan failing.

The ethics coda: supplementing is the vegan position

Is taking a B12 supplement un-vegan?

The interview asks, sincerely, why vegans would trust industries that torture animals, and then aims that question at a bacterially fermented vitamin. Point it in the right direction and it answers itself.

Supplemental B12 involves zero animals: cultured microbes in a tank [29, 30]. The B12 in modern animal products, by contrast, is substantially the output of the feed-supplementation pipeline documented above, the same industrial vitamin, routed through a confined animal’s body before reaching the plate [29, 30]. Between a tablet and a slaughterhouse, the tablet is not the ethical compromise. It is the ethical escape.

And there’s the movement-level accounting. Every influential vegan who persuades followers to shun B12 is, on a years-long fuse, manufacturing the future ex-vegans and cautionary headlines that anti-vegan voices feast on, doing the opposition’s work for free, with our own community’s trust as the fuel. The animals are best served by vegans who are visibly, verifiably thriving at year five, year twenty, year forty-five. The full weight of the evidence says a well-planned vegan diet delivers exactly that [5], and well-planned means, at minimum, the one nutrient our modern, sanitized food system no longer provides by accident. Fifty micrograms a day is not a crack in the vegan argument. It’s the keystone.

The book behind the interview

Is “The Enigma of Vitamin B12” credible?

The interview didn’t invent its B12 claims; it was drawing on a specific source, which the host praised on air: a self-published 2025 book, The Enigma of Vitamin B12: Nature’s Only Mistake?, by Anthea V. Hayes. It’s worth addressing by name, because its arguments are the ones circulating, and every one of them has already been answered above.

The book’s marketing frames B12 as “Nature’s only mistake” and asks, with heavy implication, why a healthy diet should require a pill and why the list of deficiency symptoms keeps growing. Laid against the evidence, each beat collapses. B12 isn’t nature’s mistake; it’s a bacterial nutrient that every animal (cow, pig, human) must obtain from microbes, which is why the animals people eat are themselves supplemented or cobalt-fed, per the roughly 55 percent feed-market fact. It wasn’t “invented” or “patented into existence” by a drug company; it was isolated in 1948 to cure a reliably fatal disease, and it’s manufactured today by bacterial fermentation, not a chemistry set. The “why so many symptoms?” rhetorical flourish mistakes a well-mapped two-enzyme biochemistry (DNA synthesis and myelin maintenance, hence the blood and nerve effects) for something suspiciously sprawling. And the implied answer, that you can safely skip it, is precisely the claim that the EPIC-Oxford data (52 percent of vegans deficient), the raw-vegan data (76 percent low), and the infant case reports refute in the only currency that matters: measured deficiency in real people. A book can ask “why is this the one nutrient not in plants?” as though it were a smoking gun. The answer is microbiology, and it has been known for decades. Provocative questions are not evidence, and a compelling narrative is not a controlled trial.

A brief word about the rest of the interview

The B12 claims did not travel alone. The same conversation asserted that contagion does not exist, that childhood vaccines are destroying nervous systems, and that fluoride, chemtrails, and calcified pineal glands explain public gullibility. A full treatment is beyond this post’s scope, but the pattern deserves one sentence: each of those claims is contradicted by evidence at every level of the same hierarchy used here, and when defending an opinion about a vitamin requires denying the germ theory of disease, the opinion is carrying more load than any opinion should. Extraordinary claims stacked on extraordinary claims do not buttress each other. They compound.

The bottom line

Vitamin B12 is a bacterial nutrient every human needs, discovered through a twenty-year scientific effort to cure a fatal disease, produced today by fermentation without a single animal, and required in amounts that cost a few dollars a year. Its deficiency has a specific laboratory fingerprint, reverses with B12 alone in placebo-controlled trials, silently spends down a multi-year bodily reserve before symptoms appear, and can end in irreversible nerve damage, which is precisely why “I feel fine and refuse testing” is the least informative sentence in this debate. Deficiency is common among omnivores, U.S. nutrition policy already tells everyone over 50 to get B12 from supplements or fortified foods, and the majority customer of the world’s B12 supply is the animal-agriculture industry itself, the fact that turns “B12 is an anti-vegan conspiracy” into an argument that refutes its own premise. Take your cyanocobalamin, 50 micrograms chewed daily or 2,000 to 2,500 once a week (500 to 1,000 daily after 65), or eat properly spaced fortified foods, get tested if you’ve lapsed, make sure the pregnant and breastfeeding vegans in your life are covered, ideally with 250 micrograms daily, and let this be the place the “great supplement scam” narrative is finally laid to rest.

Further resources

Dr. Greger’s B12 series and summary at NutritionFacts.org, including the updated recommendations infographic, plus the videos “How Long Does It Take to Become Vitamin B12 Deficient and What Are the Symptoms?”, “The Best Way to Test for Vitamin B12 Deficiency”, “The Best Source of Vitamin B12: Supplements, Shots, or Fortified Foods?”, “How Much Vitamin B12 Do We Need Each Day?”, “Are Large Weekly Doses of Vitamin B12 Safe?”, “The Optimal Vitamin B12 Dosage for Adults”, “The Optimal Vitamin B12 Dosage for Kids, Pregnancy, and Seniors”, and “The Best Type of Vitamin B12: Cyanocobalamin or Methylcobalamin?”

VeganHealth.org’s B12 hub, including “Should I Get My B12 Status Tested?”, “Vitamin B12 in Plant Foods”, “Intestinal Bacteria as a Vitamin B12 Source”, “Can a Natural Diet Require Supplements?”, and “What Every Vegan Should Know About Vitamin B12”.

Editorial note: the quantitative claims in this article, including study populations, percentages, doses, dates, discovery history, and industrial-production figures, were checked against the cited primary sources, abstracts, and regulatory documents before publication, and later additions were checked the same way. Where a claim rests on another source’s summary of a study rather than the study itself, the text attributes it to that summary.

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Last updated: October 5, 2026, 10:49 PM ET