Vitamin D3 for Fatigue
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.
Vitamin D3 for Fatigue
2 of 2 results reported a benefit, from 1 published study.
1 randomised trial, 120 people · the chart counts everything measured
- 2 reported a benefit
Colour keyReported a benefitNo clear benefitUnclearPossible harmAmber is for highlights, such as where the most research is. It never means a result was good.
- Fatigue symptomsFell by 3.3 vs 0.8in the comparison group, unit not reported on the FAS scale1 randomised trial2016 study ↗
- People reporting less fatigue2.63 timesthe odds of the comparison group1 randomised trial2016 study ↗
These are the figures the studies reported, not a prediction for any one person. Where several studies measured the same thing in the same unit, we show a simple average and say so. Every result is listed below.
See every resultThe connection
Chronic tiredness, low energy, and exhaustion not explained by other medical conditions.
Also known as: Cholecalciferol
Vitamin D3 × Fatigue: at a glance
Every published result for this pair, extracted and audited.
These charts count reported findings from published studies, grouped by reported benefit and study design. Study design is not a certainty grade.
Vitamin D3 / Fatigue: reported findings; one study may contribute several findings.
What the evidence shows
What this means: Counts describe research quantity, not treatment effectiveness or certainty.
| Category | Findings (count) |
|---|---|
| Benefit | 2 |
Study designs behind these findings
What this means: Counts describe research quantity, not treatment effectiveness or certainty.
| Category | Findings (count) |
|---|---|
| Randomised trial | 2 |
- Studies
- 1
| Study | Outcome | Reported result | Uncertainty (as reported) | Study duration |
|---|---|---|---|---|
| Effect of vitamin D3 on self-perceived fatigue: A double-blind randomized placebo-controlled trial. (PMID 28033244) | amelioration of fatigue | 72% | P=0.01; odds ratio [OR] 2.63, 95% CI for OR 1.23-5.62 | 4 weeks |
| Effect of vitamin D3 on self-perceived fatigue: A double-blind randomized placebo-controlled trial. (PMID 28033244) | 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 | 4 weeks |
Study results, as reported by the publications
Every measured outcome, one row per finding - numbers exactly as reported. Units are preserved where supplied; missing units are not inferred.
| Study and type | Reported sample and duration | Outcome measured | Reported result | What studies found |
|---|---|---|---|---|
| PMID 28033244 2016 Randomised trial | Sample (as reported): 120Duration: 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 | Sample (as reported): 120Duration: 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 |
Vitamin D3 × Fatigue: the evidence base
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 ↗02Dietary Supplementation for Fatigue Symptoms in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS)-A Systematic ReviewDorczok MC, et al. · Nutrients · 2025PMID 39940333 ↗03Vitamin D's Impact on Cancer Incidence and Mortality: A Systematic ReviewWimalawansa SJ · Nutrients · 2025PMID 40732958 ↗04Role of vitamin D as adjuvant therapy on multiple sclerosis: an updated systematic review and meta-analysis of randomized controlled trialsSerag I, et al. · European journal of medical research · 2025PMID 40797337 ↗05Psychiatric and cognitive outcomes of iron supplementation in non-anemic children, adolescents, and menstruating adults: A meta-analysis and systematic reviewFiani D, et al. · Neuroscience and biobehavioral reviews · 2025PMID 40945632 ↗06Population-based interventions for preventing falls and fall-related injuries in older peopleLewis SR, et al. · The Cochrane database of systematic reviews · 2024PMID 38180112 ↗Community experiences
Contributors volunteered; this does not establish treatment effectiveness or population incidence.
Reported changes
No publishable community breakdown is available. This does not establish that no reports exist.