Chaste Tree

The drug is the dried ripe berry, taken as a tincture of the fresh or dried fruit or as a powder. Hippocrates, Dioscorides and Theophrastus all wrote about the plant, and women’s health remains its main use in Western practice ^{22,23,24,25,26Reference 22Bone K · 2013Principles and Practice of PhytotherapyReference 23Bone K · 2003A Clinical Guide to Blending Liquid Herbs: Herbal Formulations for the Individual PatientReference 24Blumenthal M et al. · 2003The ABC Clinical Guide to HerbsReference 25Weiss R · 1988Herbal MedicineReference 26Blumenthal M · 1998ReviewThe Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines}.

The American Eclectics gave a tincture of the fresh berries as a galactagogue, to increase breast milk, and as an emmenagogue, to bring on menstruation ^{22,25,26Reference 22Bone K · 2013Principles and Practice of PhytotherapyReference 25Weiss R · 1988Herbal MedicineReference 26Blumenthal M · 1998ReviewThe Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines}. In France it was given for minor sleep disturbance in adults and children ^{22Reference 22Bone K · 2013Principles and Practice of Phytotherapy}.

Traditional uses recorded for the berry extract include menstrual disorders, premenstrual syndrome, a short luteal phase, infertility, acne, menopausal complaints and poor milk supply ^{18Reference 18Daniele C et al. · 2005Systematic reviewVitex agnus castus: a systematic review of adverse eventsView study →}.

In the ancient world the plant was a symbol of chastity and was taken to suppress sexual desire, which is where its English and Latin names come from ^{22,24Reference 22Bone K · 2013Principles and Practice of PhytotherapyReference 24Blumenthal M et al. · 2003The ABC Clinical Guide to Herbs}. Monasteries used the peppery dried fruit in place of pepper, and it is still called monk’s pepper.

The landmark trial is a German randomised, double-blind, placebo-controlled study of the Ze 440 extract. In 170 women taking one tablet daily over three cycles, 52% on the extract had their symptoms halved, against 24% on placebo. The symptoms scored were irritability, mood change, anger, headache, breast fullness and bloating ^{1Reference 1Schellenberg R et al. · 7279RCTSchellenberg R. Treatment for the premenstrual syndrome with agnus castus fruit extract (Ze 440): prospective, randomised, placebo controlled study. BMJ. 2001;322(7279):134–137. https://pubmed.ncbi.nlm.nih.gov/11159568/View study →}.

A multi-centre placebo-controlled trial of the BNO 1095 extract in 217 Chinese women ^{2Reference 2He Z et al. · 2009RCTTreatment for premenstrual syndrome with Vitex agnus castus (BNO 1095): a prospective, randomized, multi-center placebo-controlled study in ChinaView study →} and a further placebo-controlled trial in 128 women ^{3Reference 3Zamani M et al. · 2012Clinical trialTherapeutic effect of Vitex agnus castus in patients with premenstrual syndromeView study →} reported similar benefit. An older controlled trial found the extract comparable to pyridoxine (vitamin B6) on the overall symptom score, and better for breast tenderness, fluid retention, tension and headache ^{4Reference 4Lauritzen C et al. · 1997RCTTreatment of premenstrual tension syndrome with Vitex agnus castus: controlled, double-blind study versus pyridoxineView study →}.

A 2017 meta-analysis of the placebo-controlled trials found a large pooled effect (Hedges g −1.21), but with extremely high heterogeneity and signs of publication bias, and its authors judged the pooled figure exploratory ^{6Reference 6Verkaik S et al. · 2017Meta-analysisThe treatment of premenstrual syndrome with preparations of Vitex agnus castus: a systematic review and meta-analysisView study →}. A 2019 meta-analysis limited to three well-characterised trials (520 women) found women 2.57 times more likely to respond on the extract than on placebo ^{5Reference 5Csupor D et al. · 2019Meta-analysisVitex agnus-castus in premenstrual syndrome: a meta-analysis of double-blind randomised controlled trialsView study →}.

A separate systematic review of eight trials found all of them positive for PMS or PMDD. It noted that differing diagnostic criteria, outcome measures and extracts make the trials hard to compare ^{7Reference 7Cerqueira RO et al. · 2017Systematic reviewVitex agnus castus for premenstrual syndrome and premenstrual dysphoric disorder: a systematic reviewView study →}.

Gap: the trials tested Ze 440 and BNO 1095, and the whole-berry and tincture forms sold to consumers were rarely among them. Effect sizes vary widely between studies, and there are no large, low-bias head-to-head trials against an SSRI or an oral contraceptive.

Cyclic breast pain is linked to latent hyperprolactinaemia, a tendency to release too much prolactin, which chaste tree lowers ^{9,10Reference 9Ooi SL et al. · 2020Meta-analysisVitex agnus-castus for the treatment of cyclic mastalgia: a systematic review and meta-analysisView study →Reference 10Wuttke W et al. · 2003Chaste tree (Vitex agnus-castus) — pharmacology and clinical indicationsView study →}. A 2020 systematic review and meta-analysis pooled six placebo-controlled trials (718 women) and found a moderate effect favouring the extract (standardised mean difference 0.67) for breast-pain intensity. Typical doses were 20–40 mg/day over three months ^{9Reference 9Ooi SL et al. · 2020Meta-analysisVitex agnus-castus for the treatment of cyclic mastalgia: a systematic review and meta-analysisView study →}.

Across the wider set of 25 studies, seven trials found chaste tree non-inferior to comparators including dopamine agonists, NSAIDs, SSRIs and hormonal contraceptives, with only mild, reversible adverse events ^{9Reference 9Ooi SL et al. · 2020Meta-analysisVitex agnus-castus for the treatment of cyclic mastalgia: a systematic review and meta-analysisView study →}.

A pharmacology review identifies premenstrual breast pain as the symptom most convincingly helped by the extract in double-blind placebo-controlled studies ^{10Reference 10Wuttke W et al. · 2003Chaste tree (Vitex agnus-castus) — pharmacology and clinical indicationsView study →}.

A retrospective cohort of 1,700 women taking two chaste-tree products for three months recorded breast tenderness falling from 39.9% to 0.8% of patients, and less menstrual pain in 85.2%. Women whose main complaint was breast pain improved less than those with period pain ^{20Reference 20Höller M et al. · 2024Clinical trialUse of Vitex agnus-castus in patients with menstrual cycle disorders: a single-center retrospective longitudinal cohort studyView study →}.

That study was uncontrolled and unblinded, and several of its authors were employees of the company that makes both products ^{20Reference 20Höller M et al. · 2024Clinical trialUse of Vitex agnus-castus in patients with menstrual cycle disorders: a single-center retrospective longitudinal cohort studyView study →}.

Gap: risk of bias was unclear in most of the pooled studies, and as with PMS the benefit is tied to specific standardised extracts rather than the whole berry.

A randomised double-blind placebo-controlled trial enrolled 52 women with a short luteal phase due to latent hyperprolactinaemia, of whom 37 were evaluated. After three months on 20 mg of extract daily, prolactin release had fallen, the luteal phase had returned to normal length and progesterone had normalised, changes seen only in the treated group. Two treated women became pregnant during the study ^{11Reference 11Milewicz A et al. · 1993Vitex agnus castus extract in the treatment of luteal phase defects due to latent hyperprolactinaemiaView study →}.

Chaste-tree extracts inhibit both resting and stimulated prolactin secretion from rat pituitary cells in vitro, and a dopamine-receptor blocker abolishes the effect ^{12Reference 12Sliutz G et al. · 1993AnimalAgnus castus extracts inhibit prolactin secretion of rat pituitary cellsView study →}.

A 2023 review concluded that the herb may be a useful and safe option for selected patients with mild hyperprolactinaemia, and noted that the supporting data are small and inconsistent, with no large RCT ^{13Reference 13Puglia LT et al. · 2023Vitex agnus castus effects on hyperprolactinaemiaView study →}.

Gap: one small RCT plus a mechanism.

PMDD is the severe, mood-dominant end of the premenstrual spectrum. In a two-month comparator trial in 41 women, chaste-tree extract was tested against the SSRI fluoxetine. Response rates were similar (57.9% on the extract, 68.4% on fluoxetine), with fluoxetine better for psychological symptoms and the extract better for physical ones ^{8Reference 8Atmaca M et al. · 2003Fluoxetine versus Vitex agnus castus extract in the treatment of premenstrual dysphoric disorderView study →}.

PMDD is also covered within the broader PMS systematic reviews, which treat it as a subset of the premenstrual indication ^{7Reference 7Cerqueira RO et al. · 2017Systematic reviewVitex agnus castus for premenstrual syndrome and premenstrual dysphoric disorder: a systematic reviewView study →}.

Gap: the pivotal trial had no placebo arm and was only single-blind. It shows rough parity with an SSRI, which is not the same as showing that either beat placebo in this population.

A randomised double-blind placebo-controlled trial in 60 women with PCOS gave 5.8 mg of standardised extract daily for 12 weeks. Against placebo it improved oxidative-stress markers, insulin resistance (HOMA-IR), blood lipids, menstrual frequency and a hirsutism score ^{14Reference 14Hatami A et al. · 2026RCTThe effect of Vitex agnus-castus on oxidative stress, lipid profile and insulin resistance in women with polycystic ovary syndrome: a randomised, double-blind controlled trialView study →}.

In rat models of PCOS, chaste-tree extract lowered anti-Müllerian hormone and altered ovarian gene expression ^{15Reference 15Abbaszadeh M et al. · 2026AnimalVitex agnus-castus extract improved the endocrine profile and gene expression in rat ovaries with polycystic ovary syndromeView study →}, and changed hypothalamic KISS-1 (kisspeptin) expression ^{16Reference 16Feyzollahi Z et al. · 2021AnimalEffect of Vitex agnus-castus ethanolic extract on hypothalamic KISS-1 gene expression in a rat model of polycystic ovary syndromeView study →}.

Gap: a single small human trial; the metabolic and oxidative-stress findings have not been independently replicated.

The antioxidant findings come from the PCOS trial, where the extract raised total antioxidant capacity, glutathione peroxidase and reduced glutathione, and lowered malondialdehyde and oxidative-stress indices ^{14Reference 14Hatami A et al. · 2026RCTThe effect of Vitex agnus-castus on oxidative stress, lipid profile and insulin resistance in women with polycystic ovary syndrome: a randomised, double-blind controlled trialView study →}. This fits the flavonoid and phenolic-acid content of the berry.

Gap: no dedicated antioxidant trial exists; the finding rests on secondary endpoints of a single study.

In a mouse model of lipopolysaccharide-induced acute lung injury, chaste-tree extract reduced lung oedema, lactate dehydrogenase leakage and inflammatory markers ^{17Reference 17Ibrahim SRM et al. · 2019AnimalVitex agnus-castus safeguards the lung against lipopolysaccharide-induced toxicity in miceView study →}. The flavone casticin, one of the standardisation markers, has been studied as an inhibitor of NF-κB inflammatory signalling.

Gap: animal and cell models only, and the doses and routes used don’t correspond to taking the berry by mouth.

Side effects. Across clinical trials, post-marketing surveillance and spontaneous reports, adverse events are mild and reversible. The most common are nausea, headache, digestive upset, menstrual changes, acne, itching and rash ^{18Reference 18Daniele C et al. · 2005Systematic reviewVitex agnus castus: a systematic review of adverse eventsView study →}.

Dopamine-acting drugs. Because the herb lowers prolactin through the dopamine system, interactions with dopamine agonists and dopamine antagonists (such as antipsychotics and metoclopramide) cannot be excluded ^{18,27Reference 18Daniele C et al. · 2005Systematic reviewVitex agnus castus: a systematic review of adverse eventsView study →Reference 27Committee on Herbal Medicinal Products ( · 2017ReviewEuropean Union herbal monograph on Vitex agnus-castus L., fructusView study →}. No interactions have been reported, and there are no formal interaction studies ^{18Reference 18Daniele C et al. · 2005Systematic reviewVitex agnus castus: a systematic review of adverse eventsView study →}.

Drug metabolism. In laboratory tests, a commercial chaste-tree berry preparation inhibited the drug-metabolising enzymes CYP2C19 and CYP3A4, but not CYP1A1 or CYP2C9 ^{29Reference 29Ho SH et al. · 2011The effects of commercial preparations of herbal supplements commonly used by women on the biotransformation of fluorogenic substrates by human cytochromes P450View study →}. Whether this changes drug levels in people has not been studied.

Hormonal medicines. It is best avoided alongside combined oral contraceptives, progesterone preparations and hormone-replacement therapy ^{18Reference 18Daniele C et al. · 2005Systematic reviewVitex agnus castus: a systematic review of adverse eventsView study →}. The EU herbal monograph advises anyone using oestrogens or anti-oestrogens, or with a history of oestrogen-sensitive cancer, to consult a doctor before use ^{27Reference 27Committee on Herbal Medicinal Products ( · 2017ReviewEuropean Union herbal monograph on Vitex agnus-castus L., fructusView study →}.

Pituitary conditions. The berry is thought to act on the pituitary and hypothalamus. People with a history of pituitary disorder should consult a doctor first, and in someone with a prolactin-secreting pituitary tumour it can mask the tumour’s symptoms ^{27Reference 27Committee on Herbal Medicinal Products ( · 2017ReviewEuropean Union herbal monograph on Vitex agnus-castus L., fructusView study →}.

Children and adolescents. Use under 18 is not recommended because there are no adequate data ^{27Reference 27Committee on Herbal Medicinal Products ( · 2017ReviewEuropean Union herbal monograph on Vitex agnus-castus L., fructusView study →}.

Period pain and quality. It may aggravate spasmodic period pain that is not part of PMS, and commercial material is often adulterated with other Vitex species ^{22Reference 22Bone K · 2013Principles and Practice of Phytotherapy}.