Myth-buster
Vitamin D cut psoriasis severity by 3.3 points in a meta-analysis — but 2 of the 3 studies that went into it found no benefit.
This isn't a breakthrough — it's a provocative signal from a small, low-certainty evidence base that leaves the overall picture genuinely mixed.
A systematic review of 3 studies (463 people total) found vitamin D supplementation modestly reduced psoriasis severity scores. However, only 1 of those 3 studies showed a clear benefit — the other two found no meaningful effect — and the overall quality of the evidence is rated low. The same analysis also tested other supplements, and none beat all others across every outcome, so there's no simple winner here.
Where this fits in the evidence
Pillser has synthesized 3 studies on Vitamin D for Reduced Psoriasis Area and Severity Index — overall evidence strength: Low.
Across 3 clinical studies (1 systematic review, 2 meta-analyses), 1 reported a moderate beneficial effect of vitamin D supplementation on reducing PASI scores (mean difference = -3.29, significant), while 2 found no significant effect (small neutral). The aggregate evidence is mixed, with a predominant neutral small effect. Most studies involved psoriasis patients, but dosing and duration were not consistently reported.
The study
- Systematic Review
- n = 463
- 2025-12-11
- Frontiers in nutrition
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.