New evidence
Vitamin D supplementation lowered insulin resistance by 0.47 points in PCOS patients — but only for insulin and inflammatory markers, not glucose or cholesterol.
This is the first solid meta-analysis linking vitamin D to improved insulin resistance in PCOS, but it's a single early result on a specific clinical population — don't assume the same benefit applies to everyone or to broader metabolic health.
In women with polycystic ovarian syndrome, taking vitamin D reduced insulin resistance (measured by HOMA-IR), fasting insulin, and the inflammatory marker hs-CRP, as well as total testosterone. However, it did not change fasting blood sugar, cholesterol, or sex hormone-binding globulin, meaning the effect was narrower than a general metabolic fix — and since the dose wasn't specified, there's no clear guidance on how much to take.
Where this fits in the evidence
This is among the first studies we've indexed on Vitamin D for Reduced Homeostatic Model Assessment-Insulin Resistance Index — treat it as an early signal until more research accumulates.
The study
- Meta-Analysis
- 2026-01-02
- Medicine
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.