What is the recommended dosage for Vitamin B12?

Vegans: 250-1,000 mcg/day; General: 2.4 mcg/day (RDA); Metformin Users: 1,000 mcg/day; Supplementation: 500-1,000 mcg/day methylcobalamin

What are the side effects of Vitamin B12?

Potential side effects include: Acne (rare, at high doses), Diarrhea (rare), Generally very well tolerated.

What is vitamin B12 and how may it relate to weight management?

Vitamin B12 (cobalamin) is essential for red blood cell formation, neurological function, and energy metabolism. B12 deficiency causes fatigue and weakness, which may impair exercise capacity. While B12 injections are marketed for weight loss, there is no strong clinical evidence that B12 supplementation promotes weight loss in non-deficient individuals.

What dosage of vitamin B12 is typically used in supplementation?

The RDA for vitamin B12 is 2.4 mcg per day for adults. Supplements commonly contain 500–5,000 mcg. Individuals at risk of deficiency include those over 50, vegans, vegetarians, and people with pernicious anemia or malabsorption. Both oral and sublingual forms are available; injections are used for severe deficiency.

What are the potential side effects of vitamin B12 supplements?

Oral vitamin B12 is generally very well tolerated, even at high doses, as excess is excreted in urine. Rare side effects include skin reactions and mild diarrhea. Injectable B12 may rarely cause injection site reactions. There is no established tolerable upper intake level for B12 due to its low toxicity potential.

Vitamin B12
Vitamin B12

vitamin_mineral

Aussi connu sous le nom de: Cobalamin, Methylcobalamin, Cyanocobalamin, Hydroxocobalamin, Adenosylcobalamin

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About

An essential cofactor for fatty acid metabolism and red blood cell formation. B12 deficiency — which is common in metformin users (10-30%) and vegans — impairs mitochondrial fatty acid oxidation and causes fatigue that limits physical activity. Benefits for weight management are primarily seen when correcting deficiency.

How It Works

Essential cofactor for methionine synthase (homocysteine remethylation) and methylmalonyl-CoA mutase (fatty acid and amino acid metabolism). B12 deficiency impairs mitochondrial fatty acid oxidation, leading to abnormal lipid accumulation. Also required for proper red blood cell formation — deficiency causes megaloblastic anemia with profound fatigue, reducing physical activity. Metformin depletes B12 in 10-30% of users.

Evidence For Conditions

Pathologie	Note	Études	Participants
Post-Bariatric Nutritional Support	B	10	1000	Voir →
Slow Metabolism	C	5	9000	Voir →

Side Effects

Acne (rare, at high doses)
Diarrhea (rare)
Generally very well tolerated

Drug & Supplement Interactions

Metformin (depletes B12 — monitor levels)
Proton pump inhibitors (reduced absorption)
H2 receptor antagonists (reduced absorption)
Colchicine (reduced absorption)

Informez toujours votre professionnel de santé de tous les compléments alimentaires que vous prenez.Informez toujours votre professionnel de santé de tous les compléments que vous prenez.

Related Ingredients

B-Complex Iron Magnesium Zinc Omega-3

En bref

Posologie: Vegans: 250-1,000 mcg/day; General: 2.4 mcg/day (RDA); Metformin_Users: 1,000 mcg/day; Supplementation: 500-1,000 mcg/day methylcobalamin
Formes: sublingual tablet capsule liquid injection (medical) nasal spray
Sources naturelles: Liver, Clams, Sardines, Beef, Tuna, Fortified nutritional yeast, Fortified cereals
Limite supérieure: No established UL (water-soluble, excess excreted)
Meilleur moment: Morning (may provide energy boost); sublingual for better absorption; separate from vitamin C (

Synthèse des preuves

Post-Bariatric Nutritional Support B

Slow Metabolism C

Avertissement FDA: Ces déclarations n'ont pas été évaluées par la Food and Drug Administration. Les produits et informations sur ce site ne sont pas destinés à diagnostiquer, traiter, guérir ou prévenir quelque maladie que ce soit. Les notes de preuve présentées sont basées sur notre analyse de la recherche publiée et évaluée par des pairs et ne constituent pas un avis médical. Consultez toujours votre professionnel de santé avant de commencer tout régime de compléments alimentaires.