Strong evidencevitamin
Vitamin B12 for Chronic Fatigue
B12 is a cofactor for methylmalonyl-CoA mutase and methionine synthase, essential for mitochondrial energy metabolism and the citric acid cycle. Deficiency impairs fatty acid oxidation and myelin maintenance, causing profound fatigue.
How strong is the research?
Strong evidence
Based on a randomised controlled trial (RCT) — the gold standard for establishing cause and effect.
Research source
SourceDror DK et al. · Nutrition Reviews 2008How much to take
1000–5000 mcg
Sublingual bypasses potential absorption issues. Essential to check B12 and MMA levels. Higher doses for documented deficiency.
When to take it
Best taken: morning