Nootropic profile
Vitamin B12 (Cobalamin)
Vitamin B12 is an essential water-soluble vitamin that plays a critical role in nerve function, myelin synthesis, and brain energy metabolism. Deficiency is common - especially in vegetarians, vegans, and the elderly - and can cause cognitive impairment, fatigue, and neurological damage.
Best for
Educational only: this is not medical advice. Always check with a qualified healthcare professional before starting any supplement.
What is Vitamin B12 (Cobalamin)?
Vitamin B12 (cobalamin) is one of eight B vitamins and is unique in its complexity - it is the largest and most structurally complex vitamin, and the only one that contains a metal ion (cobalt).
What it does for you
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How to take it
- RDA: 2.4 mcg/day for adults (UK NRV: 2.5 mcg/day)
- Supplemental dose: 500–1,000 mcg/day is commonly used for general brain health and energy support
- For deficiency: 1,000–2,000 mcg/day orally, or intramuscular injections as prescribed by a doctor
- Preferred forms: Methylcobalamin (active, methyl-donating form) or hydroxocobalamin (long-acting, used in injections). Cyanocobalamin is the most common...
- Sublingual: Sublingual tablets or sprays may improve absorption for those with GI issues
Watch out for
- No established upper limit: B12 has an excellent safety profile. No adverse effects have been consistently associated with high intakes from food or...
- Acne: Some individuals report acne breakouts with high-dose B12 supplementation, possibly due to altered skin microbiome.
- Drug interactions: Metformin, proton pump inhibitors (PPIs), and H2 receptor antagonists can reduce B12 absorption - regular monitoring recommended for...
- Masking folate deficiency: High B12 intake can mask the haematological signs of folate deficiency while neurological damage progresses. Ensure adequate...
- Pregnancy: Safe and essential during pregnancy for foetal neural development. Supplementation recommended for vegan and vegetarian mothers.
The science, if you're curious.
- B12 is a cofactor for methionine synthase, which produces S-adenosylmethionine (SAMe) - the primary methyl donor required for myelin formation and repair....
- Converts homocysteine to methionine, preventing toxic accumulation. Elevated homocysteine damages blood vessels, increases oxidative stress, and is strongly...
- Supports the methylation reactions needed to produce serotonin, dopamine, and norepinephrine - neurotransmitters essential for mood, motivation, and...
- Required for normal cell division in the brain and throughout the body, supporting neurogenesis and healthy blood cell production.
Where to find it
- Liver and kidneys: The richest natural sources - beef liver provides approximately 70 mcg per 100 g
- Shellfish: Clams, mussels, and oysters are excellent sources (up to 98 mcg per 100 g for clams)
- Fish: Salmon, trout, tuna, and sardines provide 2–9 mcg per serving
- Meat, eggs, dairy: Moderate sources providing 1–3 mcg per serving
- Fortified foods: Plant milks, breakfast cereals, and nutritional yeast are fortified with B12 for plant-based diets
- Supplements: Available as methylcobalamin, cyanocobalamin, hydroxocobalamin, and adenosylcobalamin in tablets, sublingual, spray, and injection forms
Frequently asked
Vitamin B12 is an essential water-soluble vitamin that plays a critical role in nerve function, myelin synthesis, and brain energy metabolism. Deficiency is common - especially in vegetarians, vegans, and the elderly - and can cause cognitive impairment, fatigue, and neurological damage.
The main benefits people report from Vitamin B12 (Cobalamin) are: Cognitive Enhancement, Energy, Focus, Longevity, Memory, Mood.
RDA: 2.4 mcg/day for adults (UK NRV: 2.5 mcg/day)Supplemental dose: 500–1,000 mcg/day is commonly used for general brain health and energy supportFor deficiency: 1,000–2,000 mcg/day orally, or intramuscular injections as prescribed by a doctorPreferred forms: Methylcobalamin (active, methyl-donating...
No established upper limit: B12 has an excellent safety profile. No adverse effects have been consistently associated with high intakes from food or...Acne: Some individuals report acne breakouts with high-dose B12 supplementation, possibly due to altered skin microbiome.Drug interactions: Metformin...
B12 is a cofactor for methionine synthase, which produces S-adenosylmethionine (SAMe) - the primary methyl donor required for myelin formation and repair....Converts homocysteine to methionine, preventing toxic accumulation. Elevated homocysteine damages blood vessels, increases oxidative stress, an...
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