Chasteberry (vitex): definition and evidence
Chasteberry, or vitex, is the fruit of the chaste tree (Vitex agnus-castus), sold as an herbal supplement for PMS, premenstrual breast pain and irregular cycles. It seems to act on the pituitary gland, lowering prolactin. Some studies suggest it eases PMS symptoms, but the evidence is mixed and of modest quality, and supplements vary in strength.
What the evidence says
| Use | Evidence |
|---|---|
| PMS symptoms, including irritability and mood | Several trials found improvement over placebo; reviews call the quality low to moderate |
| Premenstrual breast pain | Some supportive trials |
| Irregular cycles or fertility | Limited, small studies; not established |
| PMDD | Not enough evidence; proven treatments exist |
The likely mechanism is lowering prolactin, a hormone linked to breast tenderness and cycle changes, possibly with effects on dopamine. Products differ a lot in extract and dose, which makes results hard to compare.
Side effects and safety
- Usually mild: stomach upset, headache, itching, acne or spotting
- Not recommended in pregnancy or while breastfeeding
- May interact with hormonal contraception, dopamine-related medicines and fertility drugs
- Not advised for hormone-sensitive conditions without medical advice
Why it matters
Many people reach for vitex when PMS mood swings feel heavy. It may help some, but it isn't a substitute for treatments with stronger evidence, such as regular exercise, CBT or, for severe symptoms, SSRIs. Tracking your mood for two cycles before and after starting anything shows you honestly whether it's working. Compare options in supplements for PMS.
Talk to a doctor or pharmacist before taking vitex if you're pregnant, trying to conceive, on hormonal medicines, or have a history of hormone-sensitive cancer. See a doctor if premenstrual mood changes disrupt your life: that may be PMDD.
Frequently asked questions
How long does vitex take to work?
Studies usually ran for about three cycles, so it's sensible to give it two to three months and track symptoms before deciding.
Does chasteberry affect birth control?
It might. Because it acts on hormones, ask a pharmacist before combining it with hormonal contraception.
Sources
- NCCIH: Chasteberry
- van Die MD et al. Vitex agnus-castus extracts for female reproductive disorders: a systematic review of clinical trials. Planta Med (2013)
This page is for information only and isn鈥檛 medical advice. If something worries you, please talk to a doctor.
Keep reading
Do supplements help PMS? What the evidence actually saysSupplements for PMS, graded by evidence: calcium, vitamin B6, magnesium, chasteberry and more. Doses studied, side effects and interactions.
What is premenstrual syndrome (PMS)?PMS (premenstrual syndrome) is a group of physical and emotional symptoms in the days before a period that ease once it starts. Causes, symptoms and help.
Prolactin: definition and meaningProlactin is the pituitary hormone that makes breast milk. Why high prolactin can stop periods and ovulation, common causes, and when it's tested.How to deal with PMS at work and at home: practical coping tipsHow to deal with PMS in real life: plan around your cycle at work, talk to the people you live with, manage mood in the moment, and know when to get help.
What is premenstrual dysphoric disorder (PMDD)?PMDD (premenstrual dysphoric disorder) is a severe, cyclical mood condition in the week or two before a period. Symptoms, diagnosis and treatment options.