Written by the Vegums pharmacist team | Vegan Society Certified | Updated April 2026
Key Takeaways
- Vitamin B12, vitamin D, and omega-3 are the three supplements most recommended for vegans
- Many vegans are also deficient in iodine, calcium, and zinc — often overlooked
- Gummy supplements have better adherence rates than pills — you're more likely to actually take them
If you've recently gone vegan — or you've been plant-based for years and just want to make sure you're covering your bases — the question "what supplements do vegans need?" is one of the most important ones you can ask. At Vegums, our pharmacist founders spent years seeing nutrient deficiencies in clinic that could have been prevented with the right information. This guide gives you that information.
The short answer: most vegans need to supplement six key nutrients. Here's exactly what they are, why they matter, and how to approach them.
The 6 Nutrients Most Likely to Be Low on a Vegan Diet
1. Vitamin B12
B12 is the most critical supplement for vegans — full stop. It's found almost exclusively in animal products, and there is no reliable plant-based source. Fortified foods like nutritional yeast and plant milks contain B12, but studies consistently show these aren't sufficient to maintain optimal levels in most people.
B12 deficiency can cause irreversible neurological damage if left untreated. Early symptoms include fatigue, brain fog, numbness or tingling in hands and feet, and mood changes. The NHS recommends vegans supplement B12 regularly — and the Vegan Society agrees.
Look for methylcobalamin (the active, most bioavailable form) rather than cyanocobalamin. The Vegums Multivit for Vegans contains methylcobalamin at a Vegan Society-recommended dose.
2. Iron
Plant-based iron (non-haem iron) is less readily absorbed than the haem iron found in meat. The NHS advises that vegans aim for approximately 1.8 times the standard iron intake — for women aged 19–50, that's up to 32mg per day. Getting that from food alone is genuinely challenging.
Iron deficiency is one of the most common nutritional deficiencies in the UK, and vegan women of childbearing age are particularly at risk. Symptoms include fatigue, pale skin, cold hands and feet, and difficulty concentrating. For a full guide, see our article on iron for vegans.
3. Vitamin D
The NHS recommends everyone in the UK — vegan or not — takes a vitamin D supplement from October through March, due to limited sunlight. But research suggests many people, particularly those who spend little time outdoors or have darker skin tones, benefit from supplementing year-round.
Vitamin D3 from animal sources is more bioavailable than D2, but vegan D3 derived from lichen is now widely available and equally effective. Look for this on your supplement label.
4. Omega-3 (DHA and EPA)
Most people know omega-3 is important for heart and brain health — but fewer realise that the forms that matter most (DHA and EPA) are almost entirely absent from plant foods. Flaxseed, chia and walnuts contain ALA, but the body converts ALA to DHA very inefficiently: studies suggest a conversion rate of just 5–10%.
The solution is algae-based omega-3 — the original source that fish get their DHA from. It's bioavailable, sustainable, and completely vegan. You can read more in our detailed guide on algae omega-3 vs fish oil.
5. Iodine
Iodine is often overlooked, but it's essential for healthy thyroid function. The main dietary sources in the UK are dairy and fish — both absent from a vegan diet. Seaweed is sometimes cited as a plant-based source, but its iodine content is wildly variable and can actually be harmful in excess.
Unless you eat seaweed regularly and consistently, a modest iodine supplement — or a multivitamin containing iodine — is the sensible approach. The daily reference intake is 150mcg.
6. Calcium
Calcium isn't a supplement most vegans think about — and in many cases, it doesn't need to be a standalone one. Calcium is found in fortified plant milks, tofu, almonds, kale, and broccoli, and many vegans who eat a varied diet will be getting adequate amounts.
However, if you're light on fortified foods or calcium-rich plants, it's worth including a supplement with calcium, ideally paired with vitamin D3 and K2 for optimal absorption into bone.
How to Test Your Nutrient Levels
The gold standard is a blood test. Your GP can test for B12, iron (ferritin), and vitamin D as part of routine blood work — and if you're symptomatic, they will often do so. If you'd prefer not to wait, private testing through services like Medichecks or Thriva can give you a complete vegan nutrient panel within a few days.
Testing every 6–12 months when you first go vegan is good practice. Once your levels are stable and you have a consistent supplement routine, annual testing is usually sufficient.
Building a Supplement Stack for Vegans
You don't need a dozen different supplements. For most vegans, a well-formulated multivitamin covering B12 (methylcobalamin), vitamin D3 (vegan lichen-derived), iodine, and key minerals is a sensible foundation. Pair this with a dedicated iron supplement if you're a woman of childbearing age or experiencing symptoms, and an algae omega-3 for DHA and EPA.
At Vegums, we've designed our range around exactly this approach. The Vegan Essentials Bundle combines our pharmacist-formulated Multivit, Super Iron Gummies, and Fish-Free Omega-3 in one subscription-friendly pack — covering all six key nutrient gaps in one go.
Why Not All Supplements Are Vegan
This surprises many people: a huge number of mainstream supplements contain hidden animal-derived ingredients. The most common culprits are:
- Gelatine capsules — most standard softgels and capsules are made from pork or bovine gelatine
- Lanolin — commonly used in vitamin D3 supplements (derived from sheep's wool)
- Fish oils — found in most standard omega-3 supplements
- Carmine (E120) — a red colourant derived from crushed insects, used in some gummies
- Shellac — an insect-derived coating used on some tablets
Every Vegums product is certified by the Vegan Society — the global gold standard for vegan certification. You won't find any of the above in our formulations.
Supplement Timing: A Pharmacist's Quick Guide
A few practical tips:
- B12 and iron: Take separately where possible — high-dose iron can interfere with B12 absorption
- Vitamin D: Fat-soluble, so best taken with a meal that contains some fat
- Iron: Best absorbed on an empty stomach, but take with a small amount of food if it causes nausea. Pair with vitamin C to boost absorption — our Super Iron Gummies include added vitamin C in every serving
- Omega-3: Take with food to improve absorption and avoid any aftertaste
The Bottom Line: What Supplements Do Vegans Need?
If you take nothing else from this guide, remember: B12 is non-negotiable for vegans, iron matters particularly for women, vitamin D is important for everyone in the UK, and algae omega-3 is the most practical way to get DHA and EPA on a plant-based diet.
Covering all of these doesn't need to be complicated or expensive. A thoughtfully formulated vegan multivitamin alongside targeted supplements for iron and omega-3 is all most people need.
Ready to cover all six key nutrients? The Vegums Vegan Essentials Bundle was formulated by our pharmacist team to do exactly that — Vegan Society certified, with no nasties, no gelatine, and no guesswork.
