Strong evidencevitamin
Vitamin D for Chronic Fatigue
Vitamin D receptors are present in skeletal muscle mitochondria. Vitamin D supports mitochondrial function, reduces inflammatory cytokines (IL-6, TNF-alpha) that drive fatigue, and modulates neuromuscular function for energy production.
How strong is the research?
Strong evidence
Based on a randomised controlled trial (RCT) — the gold standard for establishing cause and effect.
Research source
SourceNowak A et al. · Nutrients 2016How much to take
2000–4000 IU
Test 25(OH)D levels. Fatigue is a hallmark symptom of vitamin D deficiency. Target 40-60 ng/mL.
When to take it
Best taken: morning