How much B12 should I take?

The RDA is only 2.4mcg, but supplements provide 500-1000mcg because B12 absorption is inefficient at high oral doses — only about 1% is absorbed by passive diffusion when you bypass the gut’s active transport. That is actually useful: a high oral dose works even for people with absorption problems. 1000mcg daily, or 5000mcg twice a week, comfortably covers needs. B12 is water-soluble with no established upper limit, so excess is excreted.

Is sublingual B12 better than pills?

Not meaningfully. Sublingual (under-the-tongue) B12 is marketed as better absorbed, but studies comparing sublingual and oral B12 found similar effectiveness at raising B12 levels. High-dose oral B12 is absorbed well enough through passive diffusion that the delivery method is mostly a matter of preference. Pick whichever you will take consistently; do not pay a premium for sublingual.

Who actually needs a B12 supplement?

B12 supplementation clearly matters for: vegans and vegetarians (B12 is essentially absent from plant foods), adults over 50 (stomach acid declines, reducing absorption from food), people taking metformin or long-term acid-reducers (PPIs), and anyone with pernicious anemia or GI conditions affecting absorption. If you eat meat, fish, eggs, or dairy and are under 50 with normal absorption, you likely get enough from food and may not need a supplement.

Best Vitamin B12 Supplement (2026): Form, Dose & Who Needs It

Q: What is the best B12 supplement?

For most people the best B12 is a 500-1000mcg daily supplement (or 5000mcg a couple of times a week), in either methylcobalamin or cyanocobalamin form — both work. Best value is Nature Made B12 1000mcg; for a certified methylcobalamin, Thorne B12. The form and whether it is sublingual or swallowed matter far less than simply taking an adequate dose consistently if you are someone who needs it.

By Verified Supplement Data · Updated May 30, 2026 · Methodology · About Us

B12 is simple: take an adequate dose if you need it, and don't overthink the form. 500-1000mcg daily (or 5000mcg twice weekly). Methylcobalamin and cyanocobalamin both work; sublingual isn't meaningfully better than a swallowed pill.

The real question is whether you need it at all. Clear yes: vegans/vegetarians, adults 50+, metformin or PPI users. If you eat animal products and are under 50, you probably get enough from food.

Best value: Nature Made B12 1000mcg (~$0.10/day). Certified methyl: Thorne B12.

Dose: why 1000mcg when the RDA is 2.4mcg

The gap looks absurd until you understand B12 absorption. Normally B12 is absorbed via a carrier protein (intrinsic factor), but that system saturates at small amounts. At high oral doses, a separate route kicks in — passive diffusion — which absorbs only about 1% of the dose. So a 1000mcg tablet delivers roughly 10mcg absorbed, comfortably above the 2.4mcg requirement. That 1% route is also why high-dose oral B12 works even for people whose active absorption is impaired (older adults, pernicious anemia) — it sidesteps the broken machinery. B12 is water-soluble with no established upper limit, so the excess is simply excreted.

Form and delivery: mostly a non-issue

Two debates dominate B12 marketing, and both are smaller than they sound. Methylcobalamin vs cyanocobalamin: cyanocobalamin is cheap, extremely stable, and the most-studied; methylcobalamin is the "active" form that skips a conversion step. Both reliably raise B12 levels — see our full form comparison. Sublingual vs swallowed: sublingual is marketed as better absorbed, but head-to-head studies show similar effectiveness. Buy whichever you'll take consistently.

Best B12, ranked

B12 supplements ranked by cost per day
Product	Form	Dose	Servings	Price	Cost/Day	Certification	Buy
Nature Made Vitamin B12 1000 mcg Sublingual Fast Dissolve Best Value	Cyanocobalamin (sublingual)	1000mcg	150	$16.72	$0.11	USP Verified	Buy
Jarrow Formulas Methyl B-12 1000 mcg Lemon Budget Pick	Methylcobalamin	1000mcg	100	$11.92	$0.12	None	Buy
NOW Foods Methyl B-12 5000 mcg Lozenges	Methylcobalamin	5000mcg	60	$15.10	$0.25	None	Buy
Solgar Methylcobalamin (Vitamin B12) 5000 mcg Sublingual Nuggets	Methylcobalamin	5000mcg	60	$17.99	$0.30	None	Buy
Thorne Vitamin B12 as Methylcobalamin 1 mg Quality Pick	Methylcobalamin	1000mcg	60	$24.00	$0.40	NSF Certified for Sport	Buy

Which to pick

Best value: Nature Made B12 1000mcg

Nature Made B12 covers daily needs at about a dime a day. For most people who just need reliable B12, this is it.

Certified methylcobalamin: Thorne

Thorne B12 is methylcobalamin with Thorne's testing rigor — the pick if you specifically want the active form and third-party assurance.

For restoring low levels: 5000mcg options

If you're correcting a deficiency, a higher-dose option like NOW Methyl B-12 5000mcg taken a few times a week speeds replenishment. Most people maintaining levels don't need this much.

Frequently asked questions

What is the best B12 supplement?

500-1000mcg daily, methyl or cyano (both work), sublingual or pill (similar). Value: Nature Made 1000mcg. Certified methyl: Thorne. Form matters less than taking an adequate dose if you need it.

How much B12?

500-1000mcg daily or 5000mcg twice weekly. Only ~1% of a high oral dose absorbs (passive diffusion), which is why doses dwarf the 2.4mcg RDA — and why high-dose oral works despite absorption issues. No upper limit.

Is sublingual better?

Not meaningfully — studies show similar effectiveness to swallowed B12. Pick what you'll take consistently; don't pay a premium for sublingual.

Who needs B12?

Vegans/vegetarians, adults 50+, metformin and PPI users, and those with pernicious anemia or absorption issues. Meat/fish/egg/dairy eaters under 50 usually get enough from food.

Related guides

Methylcobalamin vs Cyanocobalamin
B12 for Energy & Fatigue — the honest answer
B12 for Vegans & Vegetarians — the must-take nutrient
All B12 Products

Sources

Langan RC, Goodbred AJ. "Vitamin B12 Deficiency: Recognition and Management." Am Fam Physician. 2017;96(6):384-389. PMID: 28925645
Wang H, et al. "Oral vitamin B12 versus intramuscular vitamin B12 for vitamin B12 deficiency." Cochrane Database Syst Rev. 2018;3(3):CD004655. PMID: 29543316
NIH Office of Dietary Supplements. "Vitamin B12: Fact Sheet for Health Professionals." ods.od.nih.gov