Evidence-Based Nutrient Recommendations

Vitamin B12: Vegan Sources


Is B12 Vegan?

The vitamin B12 component in B12 supplements and fortified foods is made by bacteria and sourced from bacteria cultures; it is not taken from animal products. However, some companies might put gelatin in their B12 supplements, though this appears to be less and less common. It is easy to find vegan B12 supplements on the Internet or in grocery stores in developed countries.

There are some live food supplement companies that rely on spirulina or other algae, rather than bacteria cultures, as a source of vitamin B12. You should not rely on such products for your vitamin B12 as testing has indicated it is not a reliable source of active vitamin B12 (more information).

Streptomyces griseus, a bacterium once thought to be a yeast, was the commercial source of vitamin B12 for many years (8, 9). The bacteria Propionibacterium shermanii and Pseudomonas denitrificans have now replaced S. griseus (10). At least one company, Rhone Poulenc Biochimie of France, is using a genetically engineered microorganism to produce B12 (11). Propionibacterium freudenreichii has been experimented with to produce vitamin B12 in fermented grain products (16).

Fortified Foods

There are many vegan foods fortified with B12. They include non-dairy milks, meat substitutes, breakfast cereals, and one type of nutritional yeast.

For food labels in the United States, in March of 2020, the Daily Value for B12 was lowered from the 1968 RDA of 6 µg to the current RDA of 2.4 µg.

Brewer’s and Nutritional Yeasts

Brewer’s and nutritional yeasts do not contain B12 unless they are fortified with it. There is at least one vegan, B12-fortified yeast currently on the market: Red Star Vegetarian Support Formula. (Twinlab’s SuperRich Yeast Plus contains whey).

There are some drawbacks to relying solely on B12-fortified nutritional yeast:

  • Nutritional yeast often comes from bins in health food stores. If not careful, it would be easy for a store employee to order the wrong nutritional yeast out of the distributor catalogs which often list many yeasts. It would also be easy to accidentally put the wrong yeast into the Vegetarian Support Formula bin.
  • B12 is light sensitive. Nutritional yeast is likely to be exposed to the light because it is often stored in clear bins or plastic bags.
  • We know of one vegan who thought he was getting B12 from nutritional yeast yet developed B12 deficiency symptoms that resolved upon taking a B12 supplement.

If you are trying to use Red Star Vegetarian Support Formula for B12, make sure you are actually getting what you think. It is also best to keep it in the refrigerator or freezer, out of the light.

Red Star Vegetarian Support Formula nutritional yeast has many other nutrients and is a tasty food, but it’s safest not to rely on it for one’s sole source of B12.


Tucker et al. (2000, USA, 13) found that vitamin B12 from fortified breakfast cereals and dairy products was associated with better vitamin B12 status than was B12 intake from red meat, poultry, and fish, leading the researchers to suspect that the B12 from meat might be damaged by cooking. The B12 in animal foods tends not to be cyanocobalamin, the form used in fortified foods and that is more stable during cooking. For example, in an acid medium (pH 4-7), cyanocobalamin can withstand boiling at 120° C (1).

Even so, for people wondering whether they are destroying the B12 in their fortified foods by cooking, we do not have enough evidence to know for certain, so it is safest to make sure you rely on uncooked sources of vitamin B12.


There are some concerns about vegans relying solely on multivitamins that contain only small amounts of B12 (less than about 25 µg):

  • Herbert et al. (2) (1982, USA) reported that vitamins B1, B3, C, and E, and copper and iron can damage B12. They tested 15 multivitamin preparations used daily by approximately 100 million Americans for inactive B12 analogues and all preparations contained some (6-27% of total corrinoids).
  • Vitamin C in doses of 500 mg or more taken with meals or within one hour after a meal, may diminish B12 availability or destroy the B12 (3).
  • Many multivitamins cannot be chewed, which is important for B12 absorption in some people.

That said, if a multivitamin is chewable and has 25 µg of B12 (as cyanocobalamin) or more, and taken daily, it is most likely adequate.

Safety of Supplements

In 1988, Herbert cautioned that large amounts of B12 may eventually be found to be harmful (4). In contrast, Hathcock & Troendle (5) (1991) point out that there appears to be little or no question that B12 intakes of 500-1000 µg/day are safe. The Institute of Medicine has not set an Upper Tolerable Limit for a daily vitamin B12 intake.

The cobalt and the cyanide contribution of 1000 µg/day of cyanocobalamin are considered toxicologically insignificant (5)—for more information see Side Effects of B12 Supplements.

Chewing or Swallowing Whole

Crane et al. (6) (1994, USA) noted that tablets of one vitamin company dissolved slowly in water and acid. They then conducted a study to see if vegan patients who had not previously responded to oral B12 tablets swallowed whole could improve their B12 response by chewing the tablets. 7 people chewed the tablets of 100 µg (once a week for 6 weeks) and their average serum B12 levels increased from 86 to 216 pmol/l. Of the 9 who didn’t chew, theirs increased from 91 to only 103 pmol/l. (However, a 100 µg dose once a week is not a lot of B12. The more surprising result of this experiment was the large increase in the serum B12 of the 7 people who chewed the tablets, not the small increase of those who did not chew.)

7 of these 9 then chewed 500 µg/day for 10 days and their levels rose to normal with a final average of 388 ± 174 pmol/l. Three participants could not raise their levels orally and required B12 injections to maintain serum B12 above 222 pmol/l.

A 2003 study compared 500 µg per day via the sublingual (under the tongue) and oral routes. The results were that sublingual was no better than oral B12 at raising vitamin B12 levels or improving B12 activity (as measured by homocysteine and methylmalonic acid levels). Both routes increased vitamin B12 levels effectively (12).

Oral B12 for People with Malabsorption

Studies have shown that taking large amounts of oral B12 can normalize B12 status even in people with pernicious anemia. For more information, see Oral Supplements for B12 Malabsorption.


B12 supplements should not be left in the light as prolonged light damages cyanocobalamin (7, 8)

Non-cyanocobalamin Supplements

In addition to cyanocobalamin, there are oral supplements available for methylcobalamin, adenosylcobalamin (known in the supplement industry as dibencozide and coenzyme B12), and to a lesser extent, hydroxocobalamin. See Methylcobalamin and Adenosylcobalamin.

Vitamin B12-fortified Toothpaste

B12 Toothpaste in Vegans

A 2017 randomized, double-blind, placebo-controlled trial was the first to test the efficacy of vitamin B12-fortified toothpaste in raising blood markers of vitamin B12 status (14). The trial was conducted in Germany and included 66 vegans. 22 participants in the placebo group and 31 in the intervention group were taking B12 supplements; they were asked to continue their supplementation behavior throughout the study).

Participants were instructed to use the study-issued toothpaste twice a day, brushing for two minutes each time. The treatment toothpaste contained 100 mcg B12/g toothpaste. Researchers estimated participants received 130-290 mcg B12 per day via the toothpaste, but were not able to calculate or measure how much B12 the participants absorbed.

At the end of 12 weeks, compared to their baseline values, participants in the intervention group experienced significantly increased B12 (from 197±137 to 279±134 pmol/L; p=0.001) and holotranscobalamin (from 35±35 to 64±34 pmol/L; p<0.001), significantly decreased methylmalonic acid (MMA) (from 0.303±0.361 to 0.212±0.123 µmol/L; p=0.001), and not-quite-significantly decreased total homocysteine (from 10.6±6.2 to 9.7±6.4 µmol/L; p=0.058). These changes are associated with improved B12 status.

Changes were greater in those reporting not taking B12 supplements. Participants in the placebo group did not experience significant changes in their B12 markers between baseline and the end of the intervention.

Based on this study, it appears that B12-fortified toothpaste may serve as a viable source of vitamin B12 for vegans.

B12 Toothpaste in Older Adults

A 2019 randomized, double-blind, placebo-controlled trial assessed the efficacy of vitamin B12-fortified toothpaste in a sample of 92 older adults (15). After 3 months, those receiving the treatment toothpaste (100 mcg B12/g toothpaste) experienced significantly greater B12 levels (368 vs. 295 pmol/L; p = 0.005) compared with the placebo group. Researchers concluded that B12-fortified toothpaste may be used to help prevent vitamin B12 depletion in older people.


1. Personal communication, March 6-7, 2002 with Dr. Fumio Watanabe, Kochi Women’s University, Department of Health Science, 5-15 Eikokuji-cho Kochi 780-8515 Japan.

2. Herbert V, Drivas G, Foscaldi R, Manusselis C, Colman N, Kanazawa S, Das K, Gelernt M, Herzlich B, Jennings J. Multivitamin/mineral food supplements containing vitamin B12 may also contain analogues of vitamin B12. N Engl J Med. 1982(July);307(4):255-6.

3. Groff J, Gropper S. Advanced Nutrition and Human Metabolism, 3rd ed. Wadsworth: 2000.

4. Herbert V. Vitamin B-12: plant sources, requirements, and assay. Am J Clin Nutr. 1988;48:852-8.

5. Hathcock JN, Troendle GJ. Oral cobalamin for treatment of pernicious anemia? JAMA. 1991 Jan 2;265(1):96-7.

6. Crane MG, Sample C, Patchett S, Register UD. “Vitamin B12 studies in total vegetarians (vegans). Journal of Nutritional Medicine. 1994;4:419-430.

7. Schneider Z, Stroinski A. Comprehensive B12. New York: Walter de Gruyter, 1987.

8. Linnell JC, Matthews DM. Cobalamin metabolism and its clinical aspects. Clin Sci (Lond). 1984 Feb;66(2):113-21.

9. Vitamin B12. Code of Federal Regulations. U.S. Government Printing Office. Title 21, Volume 3. Revised. April 1, 2001. CITE: 21CFR184.1945 p. 550.

10. De Baets S, Vandedrinck S, Vandamme EJ. Vitamins and Related Biofactors, Microbial Production. In: Lederberg J, ed. Encyclopedia of Microbiology, Vol 4, 2nd Ed. New York: Academic Press; 2000:837-853.

11. Correspondence between Rhone Poulenc Biochimie and Red Star Yeast. May 1, 1997.

12. Sharabi A, Cohen E, Sulkes J, Garty M. Replacement therapy for vitamin B12 deficiency: comparison between the sublingual and oral route. Br J Clin Pharmacol. 2003 Dec;56(6):635-8.

13. Tucker KL, Rich S, Rosenberg I, Jacques P, Dallal G, Wilson PW, Selhub J. Plasma vitamin B-12 concentrations relate to intake source in the Framingham Offspring study. Am J Clin Nutr. 2000 Feb;71(2):514-22.

14. Siebert AK, Obeid R, Weder S, Awwad HM, Sputtek A, Geisel J, Keller M. Vitamin B-12-fortified toothpaste improves vitamin status in vegans: a 12-wk randomized placebo-controlled study. Am J Clin Nutr. 2017 Mar;105(3):618-625. doi: 10.3945/ajcn.116.141978. Epub 2017 Jan 4.

15. Zant A, Awwad HM, Geisel J, Keller M, Obeid R. Vitamin B12-fortified toothpaste improves vitamin status in elderly people: a randomized, double-blind, placebo-controlled study. Aging Clin Exp Res. 2019 Dec;31(12):1817-1825. doi: 10.1007/s40520-019-01125-6. Epub 2019 Jan 24.

16. Xie C. In situ fortification of vitamin B12 in grain materials by fermentation with Propionibacterium freudenreichii. Department of Food and Nutrition. Faculty of Agriculture and Forestry. University of Helsinki Finland. EKT-Series 1950. Doctoral dissertation. August 2020.

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