Treating cyclical mastalgia with Vitex agnus castus
Cyclical mastalgia (breast pain that varies during the menstrual cycle) is a relatively common condition in premenstrual women.  Latent hyperprolactinaemia is suggested to be a contributing factor in the conditions aetiology. Vitex agnus castus (VAC) has been researched as a potential treatment due to its dopaminergic activity. A new systematic review and meta-analysis sought to examine the treatment efficacy of VAC on cyclic mastalgia .
Upon examining 25 relevant studies of cyclic mastalgia sufferers aged 18 – 45, the systematic review concluded that VAC had efficacy in lowering breast pain intensity whilst also decreasing serum prolactin levels. The dosage range studied was 20 – 40mg per day, taken over a 3-month duration. 
The meta-analysis considered six studies, concluding there was a moderate effect size for VAC usage in cyclic mastalgia, versus placebo (SMD: 0.67, 95% CI: 0.5-0.85). Another seven trials believed pharmacological agents such as hormonal contraceptives showed more efficacy for treating cyclic mastalgia versus VAC. 
In summary the authors concluded that whilst more clinical trials are needed, VAC was a safe and efficacious treatment for cyclic mastalgia.
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 Ooi, S., Watts, S., McClean, R., & Pak, S. (2019). Vitex Agnus-Castus for the Treatment of Cyclic Mastalgia: A Systematic Review and Meta-Analysis. Journal of Women’s Health, https://doi.org/10.1089/jwh.2019.7770