Efficacy of Vitamin D Supplementation to Alleviate Premenstrual Syndrome Symptoms: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Aim: Premenstrual Syndrome (PMS) substantially impairs quality of life, while standard pharmacologic treatments are often limited by adverse effects or contraindications. This systematic review and meta-analysis evaluated the efficacy of vitamin D supplementation compared to passive control (placebo or standard care) for PMS symptom relief. Methods: PubMed, Web of Science, Scopus, Google Scholar, and CENTRAL were searched for randomized controlled trials (RCTs) up to January 2026. The primary outcome was change in total PMS severity scores. Secondary outcomes included depression, anxiety, physical symptoms, craving, and water retention. Standardized mean differences (SMDs) with 95% confidence intervals (CI) were pooled using a random-effects model. Heterogeneity was assessed using the I2 statistic. Results: Five RCTs including 436 participants were reviewed. The overall risk of bias was rated as “some concerns” in four RCTs and “low risk” in one trial. Vitamin D significantly reduced total PMS severity (SMD: −0.78, 95% CI: −1.30, −0.26, I2 = 58.22%) as well as physical symptoms (SMD: −1.00, 95% CI: −1.99, −0.01, I2 = 90.53%) and depression (SMD: −0.78, 95% CI: −1.53, −0.02, I2 = 84.56%). No significant effects were observed for anxiety, craving, or water retention. Vitamin D was well tolerated with no reported adverse events. Conclusions: Vitamin D supplementation may reduce overall PMS severity, particularly physical and depressive symptoms. However, results show substantial heterogeneity across outcomes, and the certainty of evidence remains “very low”, underscoring the need for further high-quality, well-powered RCTs.