Big effect
Vitamin D supplementation tied to a nearly one-standard-deviation reduction in fibromyalgia pain — but the meta-analysis pooled unblinded trials and the evidence is still preliminary.
This large effect size suggests vitamin D could be a meaningful adjunct for fibromyalgia pain, but because the underlying studies were not blinded and the pairing has rarely been tested, the result should be treated as promising but not conclusive.
The meta-analysis combined several studies and found that people with fibromyalgia who took vitamin D reported significantly less pain than those who did not, with a reduction of nearly one standard deviation — a large effect. However, the studies were not blinded (participants knew they were getting vitamin D), which can bias results, and this is one of the first meta-analyses on this specific question, so more rigorous trials are needed before drawing firm conclusions.
Where this fits in the evidence
This is among the first studies we've indexed on Vitamin D for Reduced Pain Levels — treat it as an early signal until more research accumulates.
The study
- Meta-Analysis
- 2025-10-15
- Nutrients
- PubMed: 41156485
- DOI: 10.3390/nu17203232
- Full study breakdown →
This is a plain-language summary of a research finding, not medical advice. Pillser surfaces research signals to help you decide what's worth investigating — always consult a qualified professional before changing what you take.