Vitex agnus-castus L. · herb
Evidence tier: moderate
Regulates menstrual cycle and reduces PMS symptoms
Dopaminergic, and that is unusual for a herb. Bicyclic diterpenes in the fruit bind dopamine D2 receptors in the anterior pituitary. Dopamine is the brake on prolactin, so a D2 agonist LOWERS prolactin, and lowering prolactin lifts the suppression on the luteal phase, restoring progesterone relative to oestrogen. This is the leading explanation for why the strongest single symptom response is breast tenderness, which is prolactin sensitive. It is a plausible and well characterised receptor mechanism, but it is also precisely why the EMA warns that interactions with dopamine agonists and dopamine antagonists cannot be excluded.
Moderate, and honestly so. Vitex is one of the few herbs in this catalogue whose seed regulatory claim actually checks out. The EMA HMPC monograph on Vitex agnus-castus L., fructus does grant WELL ESTABLISHED USE, the evidence based tier, for premenstrual syndrome, at 20 mg of dry extract once daily, and the HMPC accepts continuous use over three months. The anchor trial is real and good: Schellenberg, BMJ 2001, a randomised double blind placebo controlled trial of the Ze 440 extract over three menstrual cycles in 170 women, with responder rates of 52% on vitex versus 24% on placebo (p<0.001) and significant improvement in five of six individual symptoms, the exception being bloating. The synthesis is where the honesty lives. The systematic review and meta analysis in the American Journal of Obstetrics and Gynecology (PMID 28237870) found 13 of 14 controlled studies positive and a large pooled effect, and then said the quiet part out loud: the high risk of bias, high heterogeneity and risk of publication bias of the included studies preclude a definitive conclusion, and the pooled treatment effects should be viewed as merely explorative and, at best, OVERESTIMATING the real treatment effect. So the direction is consistent, the regulator is satisfied, and the effect size is probably smaller than the literature says. That is a textbook moderate, not a strong. Cyclical mastalgia, breast tenderness, is the best supported single symptom and the one the dopaminergic mechanism most directly explains. Beyond PMS, the evidence thins fast: cycle regulation, fertility and menopause are not established. Safety is unremarkable at monograph doses, but the mechanism creates a real interaction surface, and the EMA says so.
EMA well established use, female adults: 20 mg of dry extract (DER 6 to 12:1, ethanol 60% m/m) once daily, for premenstrual syndrome. The HMPC accepts continuous use over three months. Traditional use preparations range from roughly 2 mg to 800 mg daily depending on the preparation, which is a hundredfold spread and a warning in itself: the trial evidence belongs to the standardised 20 mg extract, not to the category.
Daily in the morning. Requires 3+ months of consistent use.
Onset: ~84 days
Avoid in pregnancy, hormonal activity may disrupt early pregnancy. Avoid in breastfeeding (may suppress prolactin at high doses). Contraindicated with dopamine receptor antagonists. Avoid with hormone sensitive conditions unless medically supervised.
Pregnancy: avoid
Breastfeeding: avoid
Active compounds: bicyclic diterpenes (rotundifuran, clerodadienols), flavonoids (casticin), iridoid glycosides (agnuside, aucubin)
Remedies using Vitex · Browse by body system · Check it against what you take
*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.