Vegans need to supplement vitamin B12 at a minimum, and most will benefit from also supplementing vitamin D, omega-3 fatty acids, and iodine. Beyond those four, calcium, zinc, iron, and choline deserve attention depending on your specific diet, though many vegans can get enough through careful food choices. Here’s what each nutrient does, why plant-based diets fall short, and how to fill the gap.
Vitamin B12: The Non-Negotiable One
A vegan diet is almost completely devoid of vitamin B12. There is no reliable whole-food plant source, so supplementation isn’t optional. B12 is essential for nerve function, red blood cell production, and DNA synthesis. Deficiency can take years to show symptoms because your liver stores several years’ worth, but by the time numbness, fatigue, or cognitive problems appear, some nerve damage may be difficult to reverse.
The two common supplement forms are cyanocobalamin and methylcobalamin. Despite marketing claims that methylcobalamin is “more natural,” research on vegans found that cyanocobalamin maintained nearly double the active B12 blood levels compared to methylcobalamin. Absorption of the two forms is similar (about 49% vs. 44% for a 1 mcg dose), and there is no demonstrated metabolic superiority to methylcobalamin supplements.
For dosing, the standard recommendation for deficiency prevention is 50 to 250 micrograms of cyanocobalamin daily. B12 absorption relies on a carrier protein called intrinsic factor, which handles only a small amount at a time. You can either take smaller, more frequent doses (which use that carrier efficiently) or take a larger dose of 1,000 to 2,000 micrograms once or twice a week, where a small percentage absorbs passively. Liquid and chewable or sublingual forms outperform swallowed tablets in maintaining blood levels.
Vitamin D: Choose D3 Over D2
Vitamin D is difficult to get from any diet, vegan or not, and most people at higher latitudes don’t produce enough from sunlight during fall and winter months. Vegans face an additional hurdle: the most common dietary sources are fatty fish, egg yolks, and fortified dairy.
Two forms exist in supplements. D2 (ergocalciferol) is plant-derived and historically the default vegan option. D3 (cholecalciferol) is more effective at raising blood levels. One large study found D3 roughly twice as effective as D2 at restoring vitamin D levels, even when D2 was given at double the dose. Separate research has estimated D2 at roughly one-third the potency of D3. Fortunately, vegan-friendly D3 sourced from lichen is now widely available, making it the better choice. A typical maintenance dose for adults is 1,000 to 2,000 IU daily, though people with confirmed deficiency may need more under guidance.
Omega-3 Fatty Acids: ALA Alone Isn’t Enough
Your body needs three omega-3 fats: ALA, EPA, and DHA. Flaxseeds, chia seeds, and walnuts provide plenty of ALA, but the conversion from ALA to the long-chain forms your brain and cardiovascular system rely on is extremely poor. Conversion to DHA, the form most critical for brain and eye health, comes in below 0.1% of dietary ALA. That means even generous flaxseed consumption won’t meaningfully raise your DHA levels.
Algae-based EPA and DHA supplements solve this problem directly. Algae is where fish get their omega-3s in the first place, so these supplements skip the middleman. A common recommendation is 250 to 500 mg of combined EPA and DHA daily, which is the same range suggested for the general population. Look for supplements that list the EPA and DHA content separately rather than just total “omega-3.”
Iodine: Important but Easy to Overdo
The recommended iodine intake for adults is 150 micrograms per day, rising to 200 to 250 micrograms during pregnancy. Dairy is a major iodine source in many Western diets because of iodine-containing sanitizers used in milk production, not because milk is naturally rich in it. Remove dairy, and your intake can drop significantly unless you use iodized salt consistently.
Seaweed is often suggested as a natural vegan source, but it’s unreliable and potentially dangerous. Iodine content varies wildly between species and even between batches of the same product. A single 5-gram portion of kelp can contain over 22,000 micrograms of iodine, more than 14,000% of the daily recommendation and far beyond the safe upper limit of 600 micrograms per day. Prolonged excessive iodine intake from seaweed has been linked to thyroid dysfunction, including both overactive and underactive thyroid conditions. Kelp supplements should not be used as an iodine source.
A small daily supplement providing 150 micrograms, or regular use of iodized salt (about half a teaspoon provides roughly 150 micrograms), is far safer and more predictable.
Calcium: Often Adequate With Planning
Calcium doesn’t automatically require a supplement on a vegan diet, but it does require attention. Research comparing vegans and lacto-vegetarians found nearly identical calcium absorption rates (26% vs. 24%), meaning your body handles plant calcium just fine when the source is right.
The key is choosing low-oxalate greens. Kale, bok choy, broccoli, and collard greens have highly absorbable calcium. Spinach and Swiss chard, despite being calcium-rich on paper, contain oxalates that bind calcium and prevent absorption. Fortified plant milks and calcium-set tofu are also reliable sources. If your daily intake of these foods is inconsistent, a 500-milligram calcium supplement taken with a meal can bridge the gap. Adults generally need around 1,000 mg daily.
Zinc: Higher Needs Due to Phytates
Zinc from plant foods is less bioavailable because of phytates, compounds found in whole grains, legumes, nuts, and seeds. Phytates bind zinc in the digestive tract and reduce how much you absorb. Research suggests that when the phytate-to-zinc ratio in your diet consistently exceeds 20:1, zinc status can become compromised.
You can improve zinc absorption through food preparation methods that reduce phytate content: soaking beans and grains before cooking, choosing sprouted bread, and fermenting foods like tempeh. Pairing zinc-rich foods with acidic ingredients (citrus, tomatoes, vinegar) also helps. Some nutrition guidelines suggest vegans aim for up to 50% more zinc than the standard recommendation, which would put adult needs around 12 to 16 mg daily. A low-dose zinc supplement (10 to 15 mg) is reasonable if your diet is heavy in unprocessed whole grains and legumes without much soaking or sprouting.
Iron: Supplementation Isn’t Always Necessary
Plant foods contain only non-heme iron, which your body absorbs less efficiently than the heme iron in meat. Vitamin C does improve non-heme iron absorption, but the effect is far less dramatic in the context of a full day’s diet than older single-meal studies suggested. When researchers measured iron absorption across complete diets rather than isolated meals, vitamin C still helped (the correlation was statistically significant), but it wasn’t the dramatic multiplier often cited.
That said, many vegans maintain healthy iron levels without supplements, especially when eating legumes, tofu, quinoa, fortified cereals, and dark leafy greens regularly. Menstruating women and endurance athletes are at higher risk for deficiency and may benefit from a low-dose supplement or periodic blood testing. Avoid supplementing iron without knowing your levels, since excess iron is harmful and your body has no efficient way to excrete it.
Choline: The Overlooked Nutrient
Choline is essential for liver function, muscle health, and brain development. It’s found predominantly in animal-derived foods like eggs and liver, which puts vegans at a disadvantage. Vegetarians (a group that includes vegans) have the lowest choline intakes in the U.S. population, averaging about 192 mg per day. For context, the adequate intake is 550 mg for men and 425 mg for women, so even omnivores fall short: only about 10% of Americans meet the recommendation.
Soybeans, quinoa, broccoli, and shiitake mushrooms provide some choline, but it’s difficult to reach adequate levels through plant foods alone. A choline supplement in the range of 200 to 300 mg daily can help close the gap. This is especially worth considering during pregnancy, when choline needs increase and deficiency may affect fetal brain development.
Creatine: Optional but Worth Knowing About
Creatine isn’t classified as essential because your body makes it, but dietary creatine comes exclusively from meat and fish. Vegans consistently have lower muscle and brain creatine stores than meat-eaters. In a study comparing creatine supplementation across diet groups, vegetarians who supplemented scored significantly higher on visual memory tests than heavy meat-eaters, while meat-eaters saw no cognitive benefit from the same supplement. This suggests vegans have more to gain from creatine because they’re starting from a lower baseline.
Creatine monohydrate at 3 to 5 grams daily is the most studied dose for physical and cognitive performance. It’s synthesized from non-animal sources, so all creatine monohydrate supplements are vegan. This one falls firmly in the “nice to have” category rather than a health necessity.
Putting It All Together
If you want the short list, these are the supplements most vegans should take consistently: B12 (cyanocobalamin, 50 to 250 mcg daily), vitamin D3 from lichen (1,000 to 2,000 IU daily), algae-based omega-3 (250 to 500 mg EPA/DHA), and iodine (150 mcg, or use iodized salt). Calcium, zinc, and choline depend on how carefully you plan your meals. Iron should only be supplemented based on blood work. Creatine is optional but offers cognitive and physical benefits that are more pronounced for people who eat no meat at all.