Vegan Vitamin B12: Everything You Need to Know as a Vegan

Vegan Vitamin B12Let’s talk about vegan vitamin B12.

No doubt you’ve heard you need vitamin B12 as a vegan (and as a vegetarian).

And if you haven’t, now you have!

But what’s the big deal about vitamin B12?

Let’s take a look at what it is, where it comes from, why you need it, and where to get it from as a vegan.

What is vitamin B12?

Vitamin B12 is a water-soluble vitamin important for normal brain function, nervous system function, and the development of red blood cells.

It’s also used by your body to synthesize DNA and metabolize fatty, and amino, acids.1

Where does it come from?

Although it’s vital to our health, our bodies don’t have the enzymes needed to produce vitamin B12. Neither do animals, plants, or fungi.

Vitamin B12 can only be produced by bacteria, mainly anaerobic bacteria, or bacteria that lives in environments without oxygen, such as large intestines of animals.

Humans and animals are capable of producing some B12 through bacteria in their bodies, but the bacteria is located in your intestines, not your stomach.

Unfortunately, this means that any vitamin B12 your body produces in the intestines won’t be absorbed by your body because it’s already on its way to be excreted as waste.

Conclusion: The only way your body can absorb vitamin B12 is through the consumption of food or supplements.

How does my body absorb vitamin B12?

Vitamin B12 can be absorbed either through the lining of your stomach by breaking it down from food, through the tissues under your tongue through sublingual supplements, or even by your muscles by intramuscular injections.

Vitamin B12 found in animal food sources, such as meat and dairy, can only be absorbed in your stomach. This is because the vitamin is bound to the protein in meat and must be separated by the gastric acid in your stomach before it can be absorbed.2

Vegan vitamin B12 supplements and fortified foods are free from proteins. That means they skip the separation step and are directly absorbed through the tissues under your tongue instead of in your stomach.

Conclusion: Vegan vitamin B12 sources are more efficient because they don’t need to undergo protein separation to be absorbed by your body.

How much do I need?

The recommended daily intake values of vitamin B12 are established by the Food and Nutrition Board. They are shown in the chart below, values represented in micrograms (mcg).

Age Amount
0-6 Months 0.4 mcg
7-12 Months 0.5 mcg
1-3 Years 0.9 mcg
4-8 Years 1.2 mcg
9-13 Years 1.8 mcg
14+ Years 2.4 mcg

Pregnant women should ingest slightly higher daily vitamin B12 at 2.6 mcg per day during pregnancy and 2.8 mcg per day while lactating.

Where can I get vegan vitamin B12?

Bragg's Nutritional YeastVegan vitamin B12 can be found in fortified cereals, nutritional yeast, and supplements.

Theoretically, you could get by with only the B12 found in fortified cereals, but that’s the least healthy option.

Many vegans find refuge in supplementing with nutritional yeast. They add to to all their meals.

This is a hit or miss with most people though; some vegans swear by it while others can’t stand the taste.

Finally, there’s sublingual vegan vitamin B12 supplements. These come in a variety of dosages and types.

B12 supplements are by far the easiest and most efficient way for vegans to hit their daily recommended values of B12.

Here’s a quick list of some of the best vegan B12 supplements available online:

Brand Amount Type Price
Deva Vegan B-12 Tablets 1000 mcg Methyl View Price
Garden of Life Organic B-12 Spray 500 mcg Methyl View Price
Jarrow Formulas Methyl B12 Lozenges 1000 mcg Methyl View Price
Best Vitality B12 Complex Capsules 5000 mcg Methyl View Price
Now Foods Ultra B-12 Liquid 5000 mcg Cyano & Methyl View Price

It’s important to note that only about 56% of a 1mcg dose of oral vitamin B12 is absorbed by the body at any given time. After about 1-2 mcg of absorption, the more B12 you ingest, the less your body absorbs it.3

So where’s the rest of it go?

Your body stores it in your liver, usually up to a few years of worth. After that, it’s considered waste, and since vitamin B12 is water soluble, the rest passes through your urine.

That means you can’t overdose on vitamin B12. It also means that a 5,000 mcg daily supplement mostly ends up in your toilet.

Vitamin B12 Deficiency

As long as you’re taking some sort of vegan vitamin B12 supplement at least once a week, you shouldn’t be worried about developing a deficiency.

If you’re a new vegan, your liver has plenty stored up from all the animal meat you ate before transitioning; at least 6 months worth being conservative.

With that said, you should still routinely test your blood for vitamin B12 levels to stay on the safe side.

What are the symptoms of deficiency?

Here’s a list of symptoms people with vitamin B12 deficiency may suffer from.4 5 6 7 8

Please note, many of these symptoms aren’t exclusive to B12 deficiency. It’s up to you to determine whether or not you really are deficient or not by consulting with your doctor.
Vitamin B12 Deficiency

  • megaloblastic anemia
  • fatigue
  • weakness
  • constipation
  • loss of appetite
  • weight loss
  • numbing in hands/feet
  • tingling in hand/feet
  • difficulting maintaining your balance
  • depression
  • confusion
  • dementia
  • poor memory
  • soreness of your mouth/tongue

The neurological symptoms (tingling, numbness, and dementia) can occur without anemia, so early detection and treatment is vital in order to avoid irreparable damage.9

Infants can also develop a deficiency.

Common symptoms in infants include failure to thrive, movement disorders, developmental delays, and anemia.10

However, many of these symptoms in infants may occur from other underlying medical conditions. Please speak to your pediatrist if your baby shows any signs of these symptoms to determine the correct cause.

How is vitamin B12 deficiency treated?

Vitamin B12 Injection

The most effective method of treating vitamin B12 deficiency is through intramuscular injections, as they bypass most barriers to absorption.

Large doses of supplements can also be effective depending on the patient’s individual ability to absorb the vitamin.11

Trials conducted with doses of 2,000 mcg of vitamin B12 (lowered to 1000 mcg daily, then weekly, then monthly) have shown that high doses of the vitamin taken daily are just as effective as intramuscular injections. 12 13

Most countries, however, continue to treat deficiency through intramuscular injections.

Conclusion: Vitamin B12 deficiency may be treated by either intramuscular injections or a regimen of high daily doses of supplements. However, the prior is favored by most countries.


  1. Yamada, Kazuhiro (2013). “Chapter 9. Cobalt: Its Role in Health and Disease”. In Astrid Sigel, Helmut Sigel and Roland K. O. Sigel. Interrelations between Essential Metal Ions and Human Diseases. Metal Ions in Life Sciences 13. Springer. pp. 295–320.
  2. Institute of Medicine. Food and Nutrition Board. Dietary Reference Intakes: Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline. Washington, DC: National Academy Press, 1998.
  3. Carmel R. How I treat cobalamin (vitamin B12) deficiency. Blood.2008;112:2214-21.
  4. Herbert V. Vitamin B12 in Present Knowledge in Nutrition. 17th ed. Washington, DC: International Life Sciences Institute Press, 1996
  5. Combs G. Vitamin B12 in The Vitamins. New York: Academic Press, Inc., 1992
  6. Bernard MA, Nakonezny PA, Kashner TM. The effect of vitamin B12 deficiency on older veterans and its relationship to health. J Am Geriatr Soc 1998;46:1199-206.
  7. Institute of Medicine. Food and Nutrition Board. Dietary Reference Intakes: Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline. Washington, DC: National Academy Press, 1998.
  8. Healton EB, Savage DG, Brust JC, Garrett TF, Lindenbaum J. Neurological aspects of cobalamin deficiency. Medicine 1991;70:229-44.
  9. Clarke R. B-vitamins and prevention of dementia. Proc Nutr Soc 2008;67:75-81.
  10. Monsen ALB, Ueland PM. Homocysteine and methylmalonic acid in diagnosis and risk assessment from infancy to adolescent. Am J Clin Nutr 2003;78:7-21.
  11. Carmel R. How I treat cobalamin (vitamin B12) deficiency. Blood.2008;112:2214-21.
  12. Vidal-Alaball J, Butler CC, Cannings-John R, Goringe A, Hood K, McCaddon A, et al. Oral vitamin B12 versus intramuscular vitamin B12 for vitamin B12 deficiency. Cochrane Database Syst Rev 2005;(3):CD004655.
  13. Butler CC, Vidal-Alaball J, Cannings-John R, McCaddon A, Hood K, Papaioannou A, et al. Oral vitamin B12 versus intramuscular vitamin B12 for vitamin B12 deficiency: a systematic review of randomized controlled trials. Fam Pract 2006;23:279-85.

One thought on “Vegan Vitamin B12: Everything You Need to Know as a Vegan

  1. If you don’t read another word about B12, you already know all you need to know. If you want to know more, read on.

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