Last verified: 22 days ago
Vitamin B12
Also known as: cobalamin, cyanocobalamin, methylcobalamin, mecobalamin, hydroxocobalamin
Evidence under review. — Not yet rated
Essential B vitamin that supports nerve health, reduces deficiency-related symptoms, and may protect against chemo nerve damage.
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What it does
Vitamin B12 (cobalamin) is an essential water-soluble vitamin your body needs for nerve function, DNA synthesis, and red blood cell production. Clinical trial evidence suggests it can...
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Evidence quality
Evidence base hasn't been formally rated yet. See research below.
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Clinical dose
500–1000 mcg/day based on study doses
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Found in
IM8 Daily Ultimate Essentials Pro, AG1 (Athletic Greens), ALLMAX Creatine Monohydrate Powder and 17 more
What the Science Says
Vitamin B12 (cobalamin) is an essential water-soluble vitamin your body needs for nerve function, DNA synthesis, and red blood cell production. Clinical trial evidence suggests it can significantly reduce the incidence of chemotherapy-induced peripheral neuropathy in cancer patients receiving neurotoxic regimens. Severe deficiency can cause neurological and psychiatric symptoms — including delusions and cognitive impairment — that may reverse with supplementation.
What It Doesn't Do
Won't boost cognition in healthy, non-deficient teens — a 6-month fortification trial showed no cognitive improvement. Not a proven pain reliever after surgery. No evidence it improves dental health. Won't replace ibuprofen for post-surgical pain management. Not a weight-loss tool on its own.
Evidence-Based Benefits
Reduces the incidence of chemotherapy-induced peripheral neuropathy in gynecological cancer patients.
Moderate EvidenceEffective at: 500 mcg twice daily (1000 mcg/day total)
Supporting studies (click to view on PubMed):
Correcting B12 deficiency can reverse neurological and psychiatric symptoms like delusions and cognitive decline.
Weak EvidenceEffective at: No established dose from provided studies
Supporting studies (click to view on PubMed):
B12 combined with B6 and folic acid lowers homocysteine levels in overweight patients with hyperhomocysteinemia.
Weak EvidenceEffective at: No established dose from provided studies
Supporting studies (click to view on PubMed):
Cobalamin supplementation reduces cardiac oxidative stress and inflammation markers in animal models of hormonal deficiency.
Weak EvidenceEffective at: No established dose from provided studies
Supporting studies (click to view on PubMed):
Absorption & Bioavailability
Moderate — oral cyanocobalamin at 500–1000 mcg doses is used clinically, but absorption depends on intrinsic factor; high-dose oral supplementation can partially bypass this via passive diffusion. Bariatric surgery patients face chronically impaired absorption and require lifelong monitoring.
Red Flags to Watch For
- Bariatric surgery patients are at high risk for chronic B12 deficiency due to impaired absorption — supplementation alone may be insufficient without monitoring
- Nitrous oxide anesthesia can oxidize cobalamin and theoretically impair B12-dependent pathways; patients with borderline B12 status should be evaluated before procedures
- Severe B12 deficiency can cause psychiatric symptoms (delusions, cognitive impairment) that may be misdiagnosed — always test levels in at-risk populations
- Duckweed and some plant sources contain pseudo-cobalamins that may not be bioavailable — plant-based consumers should use tested supplemental forms
- Ovarian cancer patients and other cancer populations show high rates of vitamin B12 abnormalities — routine screening is recommended before surgery
Products Containing Vitamin B12
See how Vitamin B12 is used in these analyzed products:
IM8 Daily Ultimate Essentials Pro
Supplement
AG1 (Athletic Greens)
Supplement
ALLMAX Creatine Monohydrate Powder
Supplement
Jarrow Formulas B-Right®
Supplement
IM8 Daily Ultimate Essentials
Supplement
Thorne Basic Nutrients 2/Day
Supplement
Garden of Life Vitamin Code Men's Multivitamin
Nutrilite Double X
Supplement
Life Extension Two-Per-Day Multivitamin
Supplement
Garden of Life Raw Organic Meal Powder Vanilla
Gruns
Supplement
310 Hydrate Variety Box
Supplement
Vitabiotics Neuromind Plus
Supplement
310 Chocolate Icing Shake
Supplement
310 Nutrition Vanilla Crème Shake
Supplement
Life Extension Mix Capsules
Supplement
The Absorption Company Energy
Supplement
Affiliatesupps
Supplement
Ritual Essential for Women Prenatal Multivitamin
Supplement
Performance Lab Caffeine 2
Supplement
Frequently Asked Questions
What does Vitamin B12 do?
Essential B vitamin that supports nerve health, reduces deficiency-related symptoms, and may protect against chemo nerve damage.
What is the effective dose of Vitamin B12?
500–1000 mcg/day based on study doses
Is Vitamin B12 safe?
Bariatric surgery patients are at high risk for chronic B12 deficiency due to impaired absorption — supplementation alone may be insufficient without monitoring
What doesn't Vitamin B12 do?
Won't boost cognition in healthy, non-deficient teens — a 6-month fortification trial showed no cognitive improvement.
Research Sources
- PubMed
- NIH DSLD
This information is for educational purposes only and is not medical advice. Always consult a healthcare professional before starting any supplement regimen. Last updated: 2026-07-05