Chasteberry — also sold as vitex or agnus castus — is the most-researched herb for premenstrual symptoms. The results are genuinely encouraging for irritability, mood and breast tenderness, with some important caveats about study quality and who shouldn't take it.
Written by Vita Globe Editorial Team | Reviewed against peer-reviewed research and NIH guidance
Does chasteberry (vitex) work for PMS?
The research is encouraging. In a randomized, placebo-controlled trial in The BMJ, 52% of women taking chasteberry fruit extract for three cycles saw their premenstrual symptoms drop by half or more, versus 24% on placebo — with significant improvements in irritability, mood changes, anger, headache and breast fullness[2]. A 2017 meta-analysis of 14 trials also found a benefit overall[3].
Caveat: The NIH rates the evidence as low-to-moderate quality, and the meta-analysis authors believe the pooled effect is likely overestimated[1][3]. Chasteberry isn't for pregnancy, breastfeeding or hormone-sensitive conditions.
Sources: BMJ 2001 RCT · AJOG 2017 Meta-Analysis · NCCIH · Verified 2026-09-25
IN THIS ARTICLE
What is chasteberry?
Chasteberry is the peppercorn-sized fruit of the chaste tree, Vitex agnus-castus, a shrub native to the Mediterranean and Central Asia. It goes by many names — vitex, chaste tree, agnus castus and monk's pepper — and has been used for centuries for gynecological complaints[1]. Today it's one of the most popular herbal supplements for premenstrual symptoms, breast tenderness and cycle-related concerns[1].
How chasteberry is thought to work
Researchers believe compounds in chasteberry act on dopamine receptors in the pituitary gland, which can lower levels of prolactin — a hormone linked to premenstrual breast tenderness[4]. ACOG notes that its exact mode of action still isn't known and that more study is needed[5].
What the research shows for PMS
The landmark trial. The best-known study enrolled 178 women diagnosed with PMS and randomized them to a standardized chasteberry fruit extract or placebo for three menstrual cycles. By the end, 52% of women in the chasteberry group were "responders" — meaning their symptom scores dropped by 50% or more — compared with 24% on placebo. Side effects were rare and mild[2].
The meta-analyses. A 2017 systematic review and meta-analysis in the American Journal of Obstetrics & Gynecology found that 13 of 14 trials showed a positive effect for chasteberry versus placebo or comparison treatments, with a large pooled effect size[3]. The authors were careful to add that heterogeneity between studies was very high and there were signs of publication bias, so the real-world effect is "most likely overestimated"[3]. A separate systematic review applying stricter quality criteria looked at eight studies and found all eight reported positive effects for PMS and premenstrual dysphoric disorder[4].
The honest summary
- Chasteberry has more controlled research for PMS than any other herb.
- The trials consistently point in a positive direction.
- Study quality is mixed, so expect a real but more modest benefit than the most enthusiastic numbers suggest.
Which symptoms it helps most
In the BMJ trial, chasteberry significantly improved irritability, mood changes, anger, headache and breast fullness[2]. Interestingly, bloating did not improve[2] — which is one reason chasteberry is often paired with vitamin B6, a nutrient the Office on Women's Health links to relief of bloating as well as moodiness and anxiety[6].
Side effects and who should avoid it
Chasteberry is generally well tolerated short-term; fruit extracts have been used safely in studies for up to three months[1]. Side effects are usually mild — nausea, stomach upset, headache or itching[1]. Skip it or talk to your doctor first if you:
- Are pregnant, trying to conceive or breastfeeding[1]
- Have or have had a hormone-sensitive condition such as breast, uterine or ovarian cancer[1]
- Use hormonal birth control or hormone therapy
- Take dopamine-related medications (including some antipsychotics and Parkinson's drugs)
How to take chasteberry
- Take it daily, not just when symptoms hit. Studies gave chasteberry every day across the whole cycle.
- Be patient. Trials measured results after three cycles.
- Look for fruit extract. The research is on extracts of the dried fruit, not leaves or essential oil.
- Track symptoms for at least two cycles so you can see what's changing.
Our option
Vita Globe Her PMS Gummies
Chasteberry fruit extract is one of the three botanicals in the 111mg PMS Support Blend in our Her PMS Gummies, alongside dong quai and cranberry — paired with 20mg of vitamin B6 and 100mcg of black pepper extract. It's made to help ease occasional premenstrual moodiness, irritability and tension, in a lush strawberry gummy you'll look forward to.* Vegan, non-GMO and gluten-free; 60 gummies, 30 servings. Not for anyone pregnant, nursing or under 18, and check with your doctor first if you use hormonal birth control.
KEEP READING
Best Supplements for PMS · Vitamin B6 for PMS · PMS Mood Swings and Irritability · What's Actually Inside: Her PMS Gummies
Frequently asked questions
How long does vitex take to work for PMS?
Most studies measured results after three menstrual cycles[2], so plan on about three months of daily use.
Can I take chasteberry while on birth control?
Chasteberry may affect hormone-related signaling, so talk to your doctor before combining it with hormonal birth control.
Does vitex help with bloating?
In the main trial it did not significantly improve bloating, even though it helped mood, irritability, headache and breast fullness[2].
Is chasteberry the same as vitex and agnus castus?
Yes — they're all names for the fruit of the chaste tree, Vitex agnus-castus[1].
Is chasteberry safe long-term?
Research supports short-term safety up to about three months[1]. For longer use, check in with your healthcare provider.
Sources
- National Center for Complementary and Integrative Health. Chasteberry. NCCIH. nccih.nih.gov/health/chasteberry
- Schellenberg R. Treatment for the premenstrual syndrome with agnus castus fruit extract: prospective, randomised, placebo controlled study. BMJ. 2001;322(7279):134–137. doi:10.1136/bmj.322.7279.134
- Verkaik S, Kamperman AM, van Westrhenen R, Schulte PFJ. The treatment of premenstrual syndrome with preparations of Vitex agnus castus: a systematic review and meta-analysis. Am J Obstet Gynecol. 2017;217(2):150–166. doi:10.1016/j.ajog.2017.02.028
- Cerqueira RO, Frey BN, Leclerc E, Brietzke E. Vitex agnus castus for premenstrual syndrome and premenstrual dysphoric disorder: a systematic review. Arch Womens Ment Health. 2017;20(6):713–719. doi:10.1007/s00737-017-0791-0
- American College of Obstetricians and Gynecologists. Management of Premenstrual Disorders: Clinical Practice Guideline No. 7. Obstet Gynecol. 2023;142(6):1516–1533. acog.org — Management of Premenstrual Disorders
- U.S. Department of Health and Human Services, Office on Women's Health. Premenstrual syndrome (PMS). womenshealth.gov. womenshealth.gov/menstrual-cycle/premenstrual-syndrome
About the Vita Globe Editorial Team
The Vita Globe Editorial Team researches and writes our wellness content, working from peer-reviewed research, systematic reviews and guidance from bodies such as the NIH and the FDA. We cite our sources inline and update articles when the evidence changes.
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. This article is for informational purposes only and is not a substitute for medical advice. Talk to your healthcare provider before starting any new supplement, particularly if you are pregnant, nursing, taking hormonal birth control or other medication, or have a hormone-sensitive condition.
