The Best Supplements for Vegetarians and Vegans

5 min read ·
Bottom Line

Plant-based diets are healthy but create a handful of predictable gaps, and this guide covers the supplements with the strongest case plus doses that match the evidence. The one that is non-negotiable is vitamin B12 — it comes only from microbes, and unsupplemented vegans will eventually develop a deficiency that can cause irreversible nerve damage (50–100 mcg daily, or 1,000–2,000 mcg twice weekly, both work). Strong cases also exist for vegan D3, direct DHA/EPA from algal oil (plant ALA converts to DHA at well under 1%), and attention to iron, zinc, iodine, and calcium, since plant forms absorb poorly; creatine and choline are worthwhile extras. The practical rule is to target the nutrients plants genuinely can’t supply rather than supplementing reflexively.

Vitamin B12: Non-Negotiable for Vegans

Vitamin B12 is made only by microbes and reaches us through animal foods. Vegans who do not supplement will become deficient over time, and prolonged B12 deficiency can cause irreversible nerve damage. Either methylcobalamin or cyanocobalamin works for maintenance — head-to-head studies show similar results when adequate doses are used. Two practical regimens have strong evidence: 50–100 mcg daily, or 1,000–2,000 mcg twice weekly. The high-dose weekly approach works because of passive diffusion (about 1% of any oral dose is absorbed regardless of intrinsic factor), so it is reliable even for older adults with reduced absorption.

Vitamin D3 and Omega-3 DHA/EPA

Most D3 supplements come from lanolin (sheep wool, not vegan). Vegan D3 from lichen is bioequivalent and widely available — target 1,000–2,000 IU daily, adjusted by bloodwork. Conversion of plant-based ALA to EPA and DHA is poor in humans: less than ~8% to EPA and under ~4% to DHA, with conversion to DHA often well below 1%. Algal oil supplements deliver DHA (and now usually EPA) directly. Roughly 200–300 mg of DHA per day from algal oil is a reasonable minimum for general health.

Iron, Zinc, Iodine, and Calcium

Non-heme iron from plants absorbs at 2–20%, versus 15–35% for heme iron from animal foods. Iron bisglycinate is gentler on the gut than ferrous sulfate at equivalent elemental doses. Phytates in legumes and grains reduce zinc absorption, so the NIH suggests vegetarians need roughly 50% more dietary zinc than omnivores. Vegans who avoid dairy and seafood are at real risk of iodine inadequacy — 150 mcg daily of potassium iodide (or kelp standardized to a known iodine content) is a reliable solution. Calcium citrate absorbs well at any meal and does not require stomach acid, making it preferable to calcium carbonate for older adults or anyone on acid-suppressing medication.

Two Worth Considering

Creatine and carnosine (or its precursor beta-alanine) are higher in omnivores than vegetarians and respond well to supplementation. Creatine monohydrate at 3–5 g/day raises muscle creatine stores in vegans more than in omnivores at baseline and improves performance and possibly cognition. Choline is also commonly under-consumed on plant-based diets — soybeans, quinoa, and supplements (250–500 mg/day) close the gap.

Sources

  1. Melina V, Craig W, Levin S. "Position of the Academy of Nutrition and Dietetics: Vegetarian Diets." Journal of the Academy of Nutrition and Dietetics, 2016. PMID: 27886704.
  2. NIH Office of Dietary Supplements. "Vitamin B12 Health Professional Fact Sheet." ods.od.nih.gov, 2024.
  3. Saunders AV, Craig WJ, Baines SK. "Zinc and vegetarian diets." Medical Journal of Australia, 2013. PMID: 25369931.
  4. Brenna JT, et al. "Alpha-linolenic acid supplementation and conversion to n-3 long-chain polyunsaturated fatty acids in humans." Prostaglandins, Leukotrienes and Essential Fatty Acids, 2009. PMID: 19269799.
  5. Burns-Whitmore B, et al. "Alpha-Linolenic and Linoleic Fatty Acids in the Vegan Diet." Nutrients, 2019. PMID: 31373259.
  6. Kanter M, et al. "Calcium Bioavailability from Calcium Citrate and Carbonate." Journal of the American College of Nutrition, 1999. PMID: 10511328.

Reviewed against 6 peer-reviewed sources.