Vitex (Chasteberry) for Menstrual Health

Research suggests that Vitex agnus-castus shows the most consistent promise for reducing premenstrual syndrome symptoms, menstrual irregularities, breast tenderness, and elevated prolactin levels, with support from multiple reviews, a large real-world observational study of 1,700 women, and a 2017 meta-analysis pooling 17 randomized controlled trials that found a large pooled effect in favor of the herb. Studies also indicate potential relevance for PCOS-related hormonal imbalances and luteal phase insufficiency, with some reviews noting that its effects on prolactin suppression appear comparable in principle to pharmaceutical dopamine agonists, though evidence remains preliminary. However, the overall body of evidence carries significant limitations: the 2017 meta-analysis flagged high risk of bias, considerable variability across trials, and signs of publication bias, while a 2019 meta-analysis found Vitex did not significantly reduce menstrual blood loss compared to placebo and performed less well than mefenamic acid for that specific outcome. Across nearly all study types reviewed — including meta-analyses, narrative reviews, and observational data — authors consistently conclude that larger, better-designed, and more standardized clinical trials are needed before firm conclusions about efficacy can be drawn, and users should be aware that product quality among commercially available supplements can vary considerably.