A well-planned vegan or vegetarian diet can cover almost every nutrient you need. Vitamin B12 is the big exception. It isn't made by plants, so plant-based eaters need a reliable plan for it. The good news: that plan is simple.
Written by Vita Globe Editorial Team | Reviewed against NIH guidance, the Academy of Nutrition and Dietetics and peer-reviewed research
Do vegans and vegetarians need a B12 supplement?
In most cases, yes, or they need to eat B12-fortified foods regularly. B12 occurs naturally only in animal foods, so vegans and many vegetarians are at higher risk of deficiency[1]. The Academy of Nutrition and Dietetics advises vegetarians and vegans to get B12 from fortified foods or supplements[2], and a review of studies found deficiency was common among vegetarians, especially vegans[3].
Caveat: Lacto-ovo vegetarians who eat eggs and dairy often get some B12, but intake can still fall short, so it's worth checking.
Sources: NIH ODS · Academy of Nutrition and Dietetics · Pawlak et al., 2013 · Verified 2026-09-27
IN THIS ARTICLE
Why do vegans and vegetarians run low on B12?
B12 is made by microbes, not plants or animals. Animals get it from microbes and store it in their tissues, which is why meat, fish, eggs and dairy are the natural dietary sources[1]. Plant foods don't reliably contain active B12 unless they are fortified.
Because the body stores B12 in the liver, deficiency can take a long time to develop after someone changes their diet. That delay can make people assume they are fine when levels are slowly falling[4].
How common is B12 deficiency in plant-based eaters?
A review of studies measuring B12 status in vegetarians found that deficiency was common across age groups, and was generally more frequent in vegans than in other vegetarians, and in people who didn't use supplements[3]. Rates varied widely between studies because of different test methods and populations, so an individual blood test is more useful than a population average.
For how deficiency shows up, including fatigue, tingling and mood changes, see Vitamin B12 Deficiency: Signs, Causes, and What Actually Helps.
Do spirulina, nori or other plant foods count as B12 sources?
This is one of the most common B12 myths. Some algae and fermented foods contain compounds that look like B12 on certain lab tests but are inactive in humans (sometimes called B12 analogues). Reviews caution against relying on foods like spirulina for B12[4]. Some plant foods contain small, variable amounts, which makes them unreliable as your main source[1].
The reliable options are:
- Fortified foods such as many breakfast cereals, plant milks and nutritional yeast (check the label; not all are fortified).
- Supplements, which are the easiest way to get a consistent amount[2].
Our guide to the best food sources of B12 includes fortified options.
How much B12 do vegans need?
The RDA for adults is the same whatever your diet: 2.4 mcg a day (2.6 mcg in pregnancy and 2.8 mcg while breastfeeding)[1]. Because only a small fraction of a large supplement dose is absorbed, supplements often contain much more than that. We explain the math in How Much B12 Per Day Do You Need?
Pregnant and breastfeeding vegans should talk to their prenatal care provider, since a baby's B12 depends on the parent's intake[2].
The honest summary
- B12 is the one nutrient plant-based diets can't reliably provide without fortified foods or supplements.
- Deficiency is common in vegetarians and especially vegans who don't supplement.
- Spirulina and similar foods are not reliable B12 sources.
- A simple daily supplement or regular fortified foods cover the gap for most people.
Our option
Vita Globe Vitamin B12 Gummies for Adults
Our B12 Gummies for Adults are vegan-friendly, gluten-free and non-GMO, with 1,000mcg of vitamin B12 (as cyanocobalamin) per two-gummy serving. It's a simple way to cover B12 on a plant-based diet, and B12 supports red blood cell formation and cellular energy production.*
Frequently asked questions
What is the best B12 for vegans?
The most important thing is a reliable, regular source. Cyanocobalamin is the form most commonly used in supplements and fortified foods[1]. We compare forms in Methylcobalamin vs. Cyanocobalamin.
Is nutritional yeast a good source of B12?
Only if it is fortified. Check the label, because unfortified nutritional yeast doesn't reliably contain B12[1].
Do vegetarians who eat eggs and dairy need B12?
They get some B12 from eggs and dairy, but intake may still fall short, so many benefit from fortified foods or a supplement[2].
How long does it take to become B12 deficient on a vegan diet?
It varies a lot. Liver stores can delay deficiency, so symptoms may appear long after a diet change[4]. Testing is the best way to know.
Sources
- Office of Dietary Supplements, National Institutes of Health. Vitamin B12: Fact Sheet for Health Professionals. Updated July 2, 2025. ods.od.nih.gov
- Melina V, Craig W, Levin S. Position of the Academy of Nutrition and Dietetics: vegetarian diets. J Acad Nutr Diet. 2016;116(12):1970-1980. doi:10.1016/j.jand.2016.09.025
- Pawlak R, Parrott SJ, Raj S, Cullum-Dugan D, Lucus D. How prevalent is vitamin B12 deficiency among vegetarians? Nutr Rev. 2013;71(2):110-117. doi:10.1111/nure.12001
- Rizzo G, et al. Vitamin B12 among vegetarians: status, assessment and supplementation. Nutrients. 2016;8(12):767. doi:10.3390/nu8120767
About the Vita Globe Editorial Team
The Vita Globe Editorial Team researches and writes our wellness content, working from peer-reviewed research, systematic reviews and guidance from bodies such as the NIH and the FDA. We cite our sources inline and update articles when the evidence changes.
These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. This article is for informational purposes only and is not a substitute for medical advice. Talk to your healthcare provider before starting any new supplement, particularly if you are pregnant, nursing, taking medication, or caring for a child.
