Last verified: 2 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), IM8 Daily Ultimate Essentials 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
IM8 Daily Ultimate Essentials
Supplement
ALLMAX Creatine Monohydrate Powder
Supplement
Garden of Life Vitamin Code Men's Multivitamin
Nutrilite Double X
Supplement
Thorne Basic Nutrients 2/Day
Supplement
Garden of Life Raw Organic Meal Powder Vanilla
Jarrow Formulas B-Right®
Supplement
Life Extension Mix Capsules
Supplement
Purolabs Collagen Complex
Supplement
Gruns
Supplement
310 Hydrate Variety Box
Supplement
310 Nutrition Vanilla Crème Shake
Supplement
Life Extension Two-Per-Day Multivitamin
Supplement
Ritual Essential for Women Prenatal Multivitamin
Supplement
Baby & Me 2 by MegaFood
Supplement
Performance Lab Caffeine 2
Supplement
310 Chocolate Icing Shake
Supplement
Needed Prenatal Multivitamin Powder
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