Loading…
Fat-soluble vitamin synthesised in skin from UVB exposure and activated by the liver and kidneys; regulates calcium and phosphate absorption for bone health and modulates immune and mood pathways via vitamin D receptors.
Chronic tiredness, low energy, and exhaustion not explained by other medical conditions.
Also known as: Cholecalciferol
Every published result for this pair, extracted and audited.
These charts group published studies by what they reported and how they were run — green marks studies that reported a benefit for this pairing. Tiers run from pooled analyses of many trials (strongest) to one-off observational reports.
Direction of reported outcomes for Vitamin D3 in fatigue.
Study designs behind these findings.
Every measured outcome, one row per finding - numbers exactly as reported.
| Study | Design | n | Duration | Outcome measured | Reported result | Direction |
|---|---|---|---|---|---|---|
| PMID 28033244 2016 | Randomised trial | 120 | 4 weeks | amelioration of fatigue | 72% (P=0.01; odds ratio [OR] 2.63, 95% CI for OR 1.23-5.62) | Benefit |
| PMID 28033244 2016 | Randomised trial | 120 | 4 weeks | intra-individual change in the fatigue assessment scale (FAS) | -3.3 (95% confidence interval [CI] for change -14.1 to 4.1; P=0.01) | Benefit |
Hand-selected PubMed studies, linked to the originals.
Ordered by strength of evidence, then result direction.
01Differences in Ferritin, Vitamin D, and Vitamin B12 Between Fibromyalgia Patients and Healthy Individuals: A Systematic Review and Meta-AnalysisIsmail O, et al. · Musculoskeletal care · 2025PMID 39832803 ↗02Ferric Carboxymaltose (FCM)-Associated Hypophosphatemia (HPP): A Systematic ReviewMagagnoli J, et al. · American journal of hematology · 2025PMID 39935027 ↗03Dietary Supplementation for Fatigue Symptoms in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS)-A Systematic ReviewDorczok MC, et al. · Nutrients · 2025PMID 39940333 ↗04Vitamin D's Impact on Cancer Incidence and Mortality: A Systematic ReviewWimalawansa SJ · Nutrients · 2025PMID 40732958 ↗Be the first to share what you noticed with Vitamin D3 for fatigue. How we calculate this.