Vitex (chasteberry)
Two meta-analyses of placebo-controlled trials found vitex eased premenstrual symptoms, one restricted to well-described extracts and one with very mixed trials. Pooled trials also found less cyclic breast pain and lower raised prolactin. Pooled trials found no change in menstrual blood loss against placebo, and no study has tested it for fibroids. Reported side effects were mild.
- Status
- Dietary supplement in the US, not approved as a drug for any use. In the EU, the European Medicines Agency's herbal committee accepts one dry extract for premenstrual syndrome on well-established use, and other preparations for minor symptoms before a period on traditional use [1].
- Also called
- Vitex agnus-castus, vitex, chasteberry, chaste berry, chaste tree, chaste tree berry, agnus castus, monk's pepper, Agni casti fructus, Ze 440, BNO 1095
- Taken for
- premenstrual syndrome, PMS, PMDD, cyclic breast pain, heavy periods, irregular periods, fibroids, hormone balance, high prolactin, fertility
Strong several reviews agree · Moderate one review or consistent trials · Limited one or a few small studies · Untested no study in people, listed with what it rests on
Shown to help3
- ModerateShown to make remission of premenstrual symptoms about 2.6 times as likely as placebo in women, in trials of well-described extracts.
- ModerateShown to ease cyclic breast pain against placebo, with a moderate effect, and to lower raised prolactin in women of reproductive age.
- LimitedOne uncontrolled study by the manufacturer found most women reported lighter, less frequent bleeding and less period pain after 3 months, with no comparison group.
Reported risks1
What people take it for, and what was found
Shown to help3
Premenstrual syndrome
Shown to make remission of premenstrual symptoms about 2.6 times as likely as placebo in women, in trials of well-described extracts.
Compared with placebo [2][3][1]; placebo, dietary supplements or other herbal preparations [3]; placebo or an active comparator [4]
The numbers and sources
- Effect
- In 3 double-blind placebo-controlled trials of the Ze 440 and BNO 1095 extracts, women on vitex were 2.57 times as likely to have a remission of symptoms (RR 2.57, 95% CI 1.52 to 4.35) [2]. Across placebo-controlled trials, the pooled effect on total premenstrual symptoms was large (Hedges g -1.21, 95% CI -1.53 to -0.88), with very high heterogeneity (I² 91%) [3]. All 8 RCTs in a third review found benefit for PMS or PMDD [4]. In the trial the EMA reviewed, 178 women improved in irritability, mood, anger, headache and breast fullness against placebo [1].
- Population
- 520 women in 3 RCTs [2]; 14 RCTs [3]; 8 RCTs [4]; 178 women [1].
- Sources
- [2], [3], [4], [1]
- Caveats
- Review [3] found high risk of bias and signs of publication bias, and judged its pooled effect exploratory and probably an overestimate. Review [2] excluded most trials for poor description of the product used. The grade rests on the restricted analysis [2].
Cyclic breast pain
Shown to ease cyclic breast pain against placebo, with a moderate effect, and to lower raised prolactin in women of reproductive age.
Compared with placebo [5]; dopamine agonists, NSAIDs, serotonin reuptake inhibitors and hormonal contraceptives [5]
The numbers and sources
- Effect
- In 6 placebo-controlled studies, vitex reduced breast pain intensity (SMD 0.67, 95% CI 0.5 to 0.85). It lowered raised serum prolactin, and 7 trials found it not inferior to dopamine agonists, NSAIDs, serotonin reuptake inhibitors or hormonal contraceptives [5].
- Population
- 718 women aged 18 to 45 in the pooled studies, among 25 studies in the review [5].
- Sources
- [5]
- Caveats
- Risk of bias was unclear in most studies [5].
Menstrual cycle complaints in routine care
One uncontrolled study by the manufacturer found most women reported lighter, less frequent bleeding and less period pain after 3 months, with no comparison group.
Compared with before treatment, in the same women [7]
The numbers and sources
- Effect
- After 3 months of a 4 mg extract, 83.4% reported improved bleeding intensity, 79.2% improved bleeding frequency and 85.2% less period pain. Irregular cycles fell from 9.1% to 0.1% of women and breast tenderness from 39.9% to 0.8%. Cycle and period length did not change meaningfully [7].
- Population
- 1,700 women with menstrual cycle complaints, mean age 30, mostly period pain (43.8%) and breast pain (21.1%), at one center [7].
- Sources
- [7]
- Caveats
- Retrospective, single center, no control group, outcomes collected partly by telephone. Five authors were employees of the manufacturer, which funded the data management, statistics and writing support [7].
Not shown to help1
Heavy menstrual bleeding
Not shown to reduce menstrual blood loss against placebo in women. Loss scores were higher than on mefenamic acid in the first cycle, not the second.
Compared with placebo [6]; mefenamic acid [6]
The numbers and sources
- Effect
- Menstrual blood loss did not differ from placebo in the first cycle (MD 3.08, 95% CI -3.11 to 9.26) or the second (MD 0.00, 95% CI -5.75 to 5.75). Against mefenamic acid, blood loss scores were higher on vitex in the first cycle (MD 7.17, 95% CI 0.33 to 14.01) and did not differ in the second (MD 12.18, 95% CI -5.57 to 29.94) [6].
- Population
- Women of reproductive age without gynecologic disorders in 5 trials [6].
- Sources
- [6]
- Caveats
- The authors rated the trials of relatively low quality. The women did not have diagnosed gynecologic disease, so the result may not apply to heavy bleeding from fibroids [6].
Claimed, not studied in people1
Fibroids
Not studied in people. A 2026 review lists vitex among herbs commonly used in traditional herbal formulas for fibroids.
No study in people. This rests on documented traditional use.
The numbers and sources
- Effect
- A review of ethnopharmacology for fibroids names Vitex agnus-castus among herbs commonly used in African, Asian and Latin American herbal formulas said to reduce fibroid size and regulate menstruation [8]. No trial of vitex for fibroid size or fibroid bleeding was found.
- Population
- Traditional herbal practice described in a literature review [8].
- Sources
- [8]
- Caveats
- Traditional use shows that people have used it, not that it changes fibroids. The pooled trials of menstrual blood loss found no effect against placebo [6].
Doses studied
The restricted PMS meta-analysis covered the Ze 440 and BNO 1095 extracts [2]. Breast pain studies typically used 20 to 40 mg a day for 3 months [5]. The routine care study used products containing 4 mg of extract for about 3 months [7]. The EMA herbal monograph covers one dry extract taken continuously over 3 months for premenstrual syndrome [1].
Risks
Reported risks1
Mild side effects
Shown in a review of trials, surveillance and reports to cause mostly mild, reversible side effects: nausea, headache, stomach upset, menstrual changes, acne, itching and rash.
The numbers and sources
- How common
- How often is not known: the sources give no rate.
- Effect
- Across clinical trials, postmarketing surveillance, surveys and spontaneous reports, adverse events were mild and reversible, most often nausea, headache, gastrointestinal upset, menstrual disorders, acne, itching and rash. No drug interactions were reported [9]. Nausea and abdominal pain were the only side effects reported in the menstrual bleeding trials [6]. Breast pain trials reported only mild, reversible events [5].
- Population
- Trials and reports of single-herb vitex products [9]; 5 menstrual bleeding trials [6]; 25 breast pain studies [5].
- Sources
- [9], [6], [5]
- Caveats
- The safety review gives no rates, and it was published in 2005 [9].
Possible, not studied in people3
Use in pregnancy and breastfeeding
Not studied in people. NCCIH cautions that preclinical evidence points to possible harm from use during pregnancy or breastfeeding.
No study in people. This rests on animal studies.
The numbers and sources
- Effect
- NCCIH cautions that some preclinical evidence points to possible harm from chasteberry use during pregnancy or breastfeeding [10]. The 2005 safety review's authors advised against use in pregnancy or lactation [9].
- Population
- Preclinical studies summarized by NCCIH [10].
- Sources
- [10], [9]
- Caveats
- No study in pregnant or breastfeeding women was found.
Hormone-sensitive conditions
Not studied in people. NCCIH cautions it may carry risk for women with hormone-sensitive conditions such as breast, uterine or ovarian cancer.
No study in people. This rests on how it acts in the body.
The numbers and sources
- Effect
- NCCIH cautions that chasteberry supplementation may carry risk for women with hormone-sensitive conditions, such as breast, uterine or ovarian cancer [10]. The EMA describes lab studies suggesting it acts on the hypothalamus and pituitary to lower prolactin [1].
- Population
- Statements from NCCIH and the EMA [10][1].
- Sources
- [10], [1]
- Caveats
- No study measured outcomes in women with these conditions.
Interaction with dopamine-acting drugs
Not studied in people. Predicted, not observed: because vitex acts on dopamine signaling, a safety review suggests it might interfere with dopamine-blocking drugs.
No study in people. This rests on how it acts in the body.
The numbers and sources
- Effect
- A systematic review of adverse events found no reported drug interactions and stated that, in theory, vitex might interfere with dopaminergic antagonists [9]. Its dopamine activity is the proposed basis for lower prolactin [5].
- Population
- Review of human safety data [9].
- Sources
- [9], [5]
- Caveats
- A theoretical interaction with no reported cases [9].
Claims tested and not found
- That vitex reduces heavy menstrual bleeding. In pooled trials, menstrual blood loss did not differ from placebo in either of two cycles [6].
Related
Sources
- European Medicines Agency. Agni casti fructus (agnus castus fruit): herbal medicine summary and EU herbal monograph (revision 1, 2018). 2020. https://www.ema.europa.eu/en/medicines/herbal/agni-casti-fructus
- Csupor D, Lantos T, Hegyi P, et al. Vitex agnus-castus in premenstrual syndrome: A meta-analysis of double-blind randomised controlled trials. Complementary Therapies in Medicine. 2019. https://doi.org/10.1016/j.ctim.2019.08.024
- Verkaik S, Kamperman AM, van Westrhenen R, et al. The treatment of premenstrual syndrome with preparations of Vitex agnus castus: a systematic review and meta-analysis. American Journal of Obstetrics and Gynecology. 2017. https://doi.org/10.1016/j.ajog.2017.02.028
- Cerqueira RO, Frey BN, Leclerc E, et al. Vitex agnus castus for premenstrual syndrome and premenstrual dysphoric disorder: a systematic review. Archives of Women's Mental Health. 2017. https://doi.org/10.1007/s00737-017-0791-0
- Ooi SL, Watts S, McClean R, et al. Vitex Agnus-Castus for the Treatment of Cyclic Mastalgia: A Systematic Review and Meta-Analysis. Journal of Women's Health. 2020. https://doi.org/10.1089/jwh.2019.7770
- Mollazadeh S, Mirghafourvand M, Abdollahi NG. The effects of Vitex agnus-castus on menstrual bleeding: A systematic review and meta-analysis. Journal of Complementary and Integrative Medicine. 2019. https://doi.org/10.1515/jcim-2018-0053
- Höller M, Steindl H, Abramov-Sommariva D, et al. Use of Vitex agnus-castus in patients with menstrual cycle disorders: a single-center retrospective longitudinal cohort study. Archives of Gynecology and Obstetrics. 2024. https://doi.org/10.1007/s00404-023-07363-4
- Manzane GV, Modise JS, Okoli BJ, et al. Ethnopharmacological insights into uterine fibroids: a review of etiology, and therapeutic potential of natural products. Frontiers in Pharmacology. 2026. https://doi.org/10.3389/fphar.2025.1714256
- Daniele C, Thompson Coon J, Pittler MH, et al. Vitex agnus castus: a systematic review of adverse events. Drug Safety. 2005. https://doi.org/10.2165/00002018-200528040-00004
- National Center for Complementary and Integrative Health. Chasteberry: Usefulness and Safety. 2025. https://www.nccih.nih.gov/health/chasteberry