Big effect
Vitamin D supplementation linked to nearly one extra dominant follicle per cycle in a meta-analysis — but the same study found no effect on a key marker of ovarian reserve.
This is one of the first meta-analyses to look at vitamin D and follicle count, so the finding is intriguing but far from settled — especially since a core measure of egg supply (AMH) didn't budge.
The analysis pooled data from several trials and found that women taking vitamin D had about 0.8 more dominant follicles (the ones that can release an egg) per menstrual cycle, along with higher ovulation and pregnancy rates. However, vitamin D didn't change anti-Müllerian hormone levels, which are often used to gauge remaining egg quantity — suggesting the benefit may be about improving current cycle quality rather than preserving long-term fertility.
Where this fits in the evidence
This is among the first studies we've indexed on Vitamin D for Increased Dominant Follicle Count — treat it as an early signal until more research accumulates.
The study
- Meta-Analysis
- 2026
- Revista da Escola de Enfermagem da U S P
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.