Vitamin
Vitamin B12 (Cobalamin)
Also known as: Adenosylcobalamin, B12, Cobalamin, Cyanocobalamin
An essential water-soluble vitamin required for red blood cell formation, neurological function, and DNA synthesis. Cyanocobalamin is a stable synthetic form commonly used in supplements.
Last reviewed June 2026 · Evidence graded from peer-reviewed research, not editorial opinion. Educational only — not medical advice.
Every Vitamin B12 (Cobalamin) product we have scored
| # | Product | Score | Per serving |
|---|---|---|---|
| 1 | Thorne Vitamin B12 | 96 A | $0.40 |
| 2 | Thorne Craving and Stress Support | 93 A | $1.33 |
| 3 | Thorne Methyl-Guard® | 93 A | $0.93 |
| 4 | Thorne Methyl-Guard Plus | 91 A | $2.07 |
| 5 | Pure Encapsulations B-Complex liquid | 91 A | $1.34 |
| 6 | Thorne Thyroid Health Complex | 90 A | $0.33 |
| 7 | Transparent Labs BULK Pre-Workout | 90 A | $1.67 |
| 8 | Nutricost Vitamin B12 Capsules | 90 A | $0.07 |
| 9 | Nature Made Vitamin B12 Maximum Strength 5000 mcg Softgels | 90 A | $0.37 |
| 10 | Life Extension Thyroid Support Complex | 90 A | $0.90 |
| 11 | Pure Encapsulations B12 liquid | 89 A | $0.73 |
| 12 | Pure Encapsulations Methylcobalamin 1,000 mcg | 89 A | $0.28 |
Scored on dose accuracy, form, label transparency and third-party testing. Per-serving cost is list price divided by servings per container. No brand pays to be listed or ranked.
Common questions
How much Vitamin B12 (Cobalamin) should I take?
The typical range is 500-2000 mcg daily. Safe for long-term use
When should I take Vitamin B12 (Cobalamin)?
Any time, sublingual preferred. Not required.
Which form of Vitamin B12 (Cobalamin) is best?
Methylcobalamin — Active form, best for general use. Other forms in the catalog: Adenosylcobalamin, Hydroxocobalamin, Cyanocobalamin, methylcobalamin (active form).
Is Vitamin B12 (Cobalamin) safe?
Commonly reported: Very well tolerated. Serious warnings: None at typical doses. Safe
Which Vitamin B12 (Cobalamin) supplement scores highest?
Thorne Vitamin B12, at 96/100. Scored on dose accuracy, form, label transparency and third-party testing — no brand pays to be listed or ranked.
Daily target & upper limit
2.4 mcg / dayVitamin B12 (Cobalamin) has an established daily reference intake. See best forms, label synonyms, upper-limit warnings, and top-scoring supplements:
Vitamin B12 (Cobalamin) dosage reference →Primary uses
- Energy production
- Nerve function
- Red blood cell formation
- Methylation support
- Neurological health
- Pernicious anemia prevention
- pregnancy support
- energy metabolism
- DNA synthesis
What systematic reviews concluded
Outcomes that systematic reviews of Vitamin B12 (Cobalamin) reached a verdict on: 7 with a benefit, 2 with no effect, 3 unclear. Each is quoted from a review and linked to it on PubMed. How these were read.
Reviews found a benefit (7)
“All IM, oral, and SL routes of administration of vitamin B12 can effectively increase the level of vitamin B12 without significant differences between them, as thought previously.” PMID 38231320 · 2 reviews
“itamin combinations were associated with significant reductions in stroke (RR 0.79, 95% CI 0.68-0.93) and MACE (RR 0.80, 95% CI 0.69-0.92).” PMID 41830012
“Combined B-vitamin supplementation effectively lowers serum Hcy levels and the incidence of vascular restenosis in patients with CHD.” PMID 41615824
“Supplementation with folic acid or L-methylfolate, B1, B12 or methylcobalamin, and vitamin D (in different doses and study duration) significantly decreased depression score scales by increasing response to standard pharmacological treatment or as monotherapy, including partial or complete remission.” PMID 35156551
“Vitamin B12 can help balance immune responses to better fight viral infections.” PMID 34791425
“vitamin B12 in the forms of methylcobalamin and cyanocobalamin may increase serum vitamin B12 levels, and resulted in decreased serum methylmalonic acid and homocysteine concentrations, and decreased pain intensity, memory loss, and impaired concentration.” PMID 34791425
and 1 more.
Reviews found no effect (2)
“we found no evidence for an effect of B12 alone or B complex supplementation on any subdomain of cognitive function outcomes” PMID 33809274 · 2 reviews
“We also found no overall effect of vitamin supplementation on measures of depression.” PMID 33809274
Not enough to say: fatigue; cardiovascular events and mortality; diabetic peripheral neuropathy.
2 findings from reviews in specific patient groups (such as cancer, pregnancy or surgery) are not shown here.
How it works
- Cofactor for methionine synthase (methylation)
- Cofactor for methylmalonyl-CoA mutase (energy metabolism)
- Essential for myelin synthesis and nerve function
Dosage
- Typical range
- 500-2000 mcg daily
- Timing
- Any time, sublingual preferred
- With food
- Not required
- Duration
- Safe for long-term use
- Special populations
- Vegans, elderly, those on metformin or PPIs need more
Forms
- Methylcobalamin
- Adenosylcobalamin
- Hydroxocobalamin
- Cyanocobalamin
Safety
Common side effects
- Very well tolerated
Contraindications
- Rare B12 hypersensitivity
Products containing Vitamin B12 (Cobalamin)
Top-scoring supplements in our catalog that list Vitamin B12 (Cobalamin) on the label. Each product is graded on Formulate's ingredient-level rubric — dose accuracy, form, transparency, and third-party testing.
Evidence notes
Well-established essential nutrient with strong evidence for deficiency treatment
Grade A: Multiple well-designed human trials support the main claims.
Cited research for Vitamin B12 (Cobalamin)
Clinical studies referenced across Formulate guides that mention vitamin b12 (cobalamin). Each links to the full study page with PubMed source + the guides that cite it.
- Pawlak et al. (2014)European Journal of Clinical Nutrition
The prevalence of cobalamin deficiency among vegetarians assessed by serum vitamin B12
- Stabler SP (2013)New England Journal of Medicine
Vitamin B12 deficiency
- Eussen SJ, de Groot LC, Clarke R, et al. (2005)Archives of Internal Medicine
Oral cyanocobalamin supplementation in older people with vitamin B12 deficiency: a dose-finding trial
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Medical disclaimer. This page is educational and does not replace advice from a qualified healthcare provider. Individual needs and risks vary — consult a professional before starting, stopping, or combining supplements, especially if you are pregnant or nursing, taking medication, or managing a health condition.