B12 deficiency develops slowly — it can take years on a vegan diet without supplementation before the body's liver stores deplete. By that point, neurological damage may already be underway. This is why B12 supplementation isn't optional for vegans; it's mandatory.
The good news: good B12 supplements are cheap, widely available, and effective. There's no complicated decision-making here once you understand the basics.
Why Vegans Need to Supplement B12
Vitamin B12 is synthesised exclusively by bacteria. It's found in animal products because animals either produce it in their gut or consume it through their feed. Plant foods don't contain B12 — and the traces sometimes found in fermented foods, algae, and nutritional yeast are either inactive analogues (that block B12 absorption rather than providing it) or in amounts too small to rely on.
For a full breakdown of what B12 does and why it matters, see what does vitamin B12 do.
Deficiency symptoms — fatigue, neurological symptoms, anaemia, memory problems — can take years to appear, but nerve damage from prolonged deficiency can be irreversible. The risk is real, the solution is simple.
Methylcobalamin vs Cyanocobalamin: Which to Choose
This is the most common question in vegan B12 supplementation.
Cyanocobalamin is the synthetic form used in most supplements and fortified foods. It's converted by the body into methylcobalamin and adenosylcobalamin (the two active forms). It's highly stable, cheap, and has the most clinical data behind it. The tiny amount of cyanide released in the conversion is far below any level of concern.
Methylcobalamin is the active form found in animal tissue. It doesn't require conversion. It's less stable than cyanocobalamin (degrades faster when exposed to light), slightly more expensive, and has a smaller clinical evidence base for supplementation specifically — though it's equally effective when tested.
The practical recommendation: Either works. Cyanocobalamin is the better-evidenced form for correcting deficiency through supplementation and is significantly cheaper. Methylcobalamin is a reasonable preference if you want the active form directly. Don't overthink this — taking either consistently is far more important than which form you choose.
Hydroxocobalamin: A third form, less common in supplements but used in some injections. Longer-lasting in the body than cyanocobalamin.
How Much B12 Do Vegans Need?
B12 absorption is unusual. It uses two separate systems:
Active absorption: A protein called intrinsic factor binds B12 in the stomach and enables active absorption in the small intestine. This system saturates at around 1.5-2mcg per meal.
Passive absorption: At very high doses, roughly 1% of B12 passively diffuses across the gut wall without intrinsic factor.
This means dose matters a lot more than with other water-soluble vitamins:
| Dosing approach | Dose | Frequency |
|---|---|---|
| Daily low dose | 25-100mcg | Daily |
| Weekly high dose | 2,000mcg | Once weekly |
| Twice weekly | 1,000mcg | Twice weekly |
All approaches work. The weekly 2,000mcg approach relies primarily on passive absorption (1% of 2,000mcg = 20mcg absorbed). Daily low doses use the active absorption system more efficiently. Either gets you to adequate B12 status.
The Vegan Society recommends either 10mcg daily or 2,000mcg weekly as evidence-based minimum targets.
Top B12 Supplements for Vegans
1. Best Overall — Jarrow Formulas Methylcobalamin 1000mcg
Form: Methylcobalamin Dose: 1,000mcg per lozenge Format: Sublingual lozenge
Sublingual (under the tongue) B12 supplements bypass the intrinsic factor system by absorbing directly through the mucous membrane. This makes them effective even in people with reduced intrinsic factor (common in older adults and some people with gut conditions). Jarrow's methylcobalamin lozenges are widely regarded as a quality standard in vegan B12 supplementation — good taste, high dose, reliable absorption. Daily use at 1,000mcg provides well above the minimum requirement.
2. Best Budget/Cyanocobalamin — Solgar Sublingual B12 1000mcg
Form: Cyanocobalamin Dose: 1,000mcg per tablet Format: Sublingual tablet
Solgar's sublingual cyanocobalamin is an excellent value option. Cyanocobalamin is more stable (longer shelf life, less degradation from light), and at 1,000mcg sublingual, absorption is reliable. Lower price per dose than methylcobalamin options without any meaningful efficacy difference for most people.
3. Best Weekly Dose — NOW Foods Methyl B-12 5000mcg
Form: Methylcobalamin Dose: 5,000mcg per lozenge Format: Sublingual lozenge
For people who prefer once or twice weekly supplementation rather than daily. At 5,000mcg sublingual, passive absorption provides well above minimum requirements. NOW Foods' quality is reliable and their price point makes this particularly cost-effective per dose. A single bottle lasts months on a weekly schedule.
4. Best for Correcting Deficiency — Thorne B12 (Methylcobalamin) Drops
Form: Methylcobalamin Dose: Adjustable (liquid drops) Format: Oral drops Third-party tested: NSF
Liquid B12 allows flexible dosing — useful when correcting established deficiency where higher doses over several weeks may be needed before stepping down to maintenance. Thorne's quality certification adds reliability. More expensive than standard sublingual tablets but useful for people correcting confirmed deficiency.
5. Best Vegan Multivitamin with B12 — Future Kind Vegan Multivitamin
Form: Methylcobalamin B12 per serving: 250mcg Additional nutrients: Vitamin D3 (from lichen), omega-3 DHA (from algae)
For vegans who want to cover multiple common deficiencies in one product. Future Kind's vegan multi is specifically designed around the nutrients most commonly deficient in vegan diets: B12 (methylcobalamin), D3 (lichen-sourced), and omega-3 (algae DHA). The B12 dose is lower than standalone supplements, but for people who are consistently supplementing and getting B12 from fortified foods, it may be adequate. Not the best choice for correcting existing deficiency — for that, use a standalone high-dose supplement.
Comparison Table
| Product | Form | Dose | Format | Best For |
|---|---|---|---|---|
| Jarrow Methylcobalamin | Methylcobalamin | 1,000mcg | Sublingual lozenge | Best all-round |
| Solgar Sublingual | Cyanocobalamin | 1,000mcg | Sublingual | Budget/stable form |
| NOW Foods 5000mcg | Methylcobalamin | 5,000mcg | Sublingual | Weekly dosers |
| Thorne Drops | Methylcobalamin | Variable | Liquid drops | Correcting deficiency |
| Future Kind Multi | Methylcobalamin | 250mcg | Capsule | All-in-one coverage |
Should Vegans Also Supplement Vitamin D?
Yes — vitamin D is the other nutrient vegans are consistently low in alongside B12, though it affects non-vegans in northern latitudes too. Most vegans should supplement both B12 and vitamin D D3 from lichen year-round. Vitamin D deficiency symptoms covers the signs to watch for.