Chasteberry has one of the longest documented histories of any herbal remedy for women’s health issues. Records suggest its use dates back at least 2,500 years to ancient Greece and Rome, where Hippocrates himself mentioned it for treating various gynaecological complaints.

The name “chasteberry” comes from the old belief that the plant could reduce sexual desire—monks in medieval Europe supposedly used it to help maintain their vows of celibacy, hence the alternative name “monk’s pepper.” Whether it actually worked for that purpose is anyone’s guess, but the tradition gives you a sense of just how long people have been experimenting with this plant.

Today, chasteberry is one of the more popular herbal supplements for premenstrual syndrome and other hormonal complaints. In Germany, it’s approved by Commission E (their equivalent of medicine regulators) for menstrual disorders and is routinely prescribed by doctors 1. But does the scientific evidence actually support these traditional uses? Let’s look at what the research shows.

What Is Chasteberry?

Chasteberry comes from the fruit of Vitex agnus-castus, a small deciduous tree in the Verbenaceae (verbena) family. The plant grows naturally around the Mediterranean and parts of Asia, and has been cultivated for centuries.

The fruits—small, dark berries about the size of peppercorns—contain the active compounds. Researchers have identified several groups of potentially bioactive chemicals in chasteberry:

Iridoid glycosides (such as agnuside and aucubin)
Flavonoids (including casticin and vitexin)
Diterpenes (rotundifuran and others)
Essential oils
Fatty acids

How chasteberry actually works isn’t entirely clear, but the leading theory involves dopamine. Studies suggest the plant’s compounds can bind to dopamine receptors in the brain, which may affect the release of prolactin from the pituitary gland 2. Since prolactin levels influence the menstrual cycle and breast tissue, this could explain some of chasteberry’s effects on women’s health.

That said, the mechanism is likely more complicated than just dopamine. Some research indicates chasteberry extracts can also interact with opioid receptors and oestrogen receptors 3. The full picture remains unclear.

Proven Benefits of Chasteberry

1. Chasteberry May Help Premenstrual Syndrome (PMS)

This is where the strongest evidence lies. Premenstrual syndrome affects roughly half of women during their reproductive years, causing physical and psychological symptoms in the week or two before menstruation begins. Symptoms can include:

Mood changes (irritability, anxiety, depression)
Breast tenderness and swelling
Bloating and water retention
Headaches
Fatigue
Changes in appetite and sleep

The symptoms typically ease within a few days of menstruation starting, but for some women they’re severe enough to significantly affect daily life.

A 2017 systematic review and meta-analysis examined three randomised, double-blind, placebo-controlled trials involving 520 women with PMS 4. The researchers found that women taking chasteberry preparations were about 2.5 times more likely to experience symptom relief compared to those taking placebo.

An earlier German study compared chasteberry extract to pyridoxine (vitamin B6), another common PMS remedy 5. After three menstrual cycles, 77% of women in the chasteberry group reported improvement, compared to 61% in the B6 group.

My honest assessment: The evidence for PMS is genuinely encouraging—more than most herbal supplements can claim. That said, the trials were fairly small and some were funded by supplement manufacturers, which always warrants a bit of scepticism. The effect also seems to work best for breast tenderness and mood symptoms rather than physical complaints like bloating. If you’re exploring natural PMS remedies, chasteberry is probably one of the better-supported options, though it’s not a cure-all.

2. Chasteberry May Ease Menopausal Symptoms

Menopause marks the end of a woman’s reproductive years, typically occurring between ages 45 and 55. The sharp decline in oestrogen and progesterone production causes symptoms that can last for years:

Hot flushes and night sweats
Sleep disturbances
Mood changes and irritability
Vaginal dryness
Difficulty concentrating

More than 80% of women experience some menopausal symptoms, and for many they persist well beyond a decade.

A 2019 randomised, double-blind trial tested chasteberry extract in 61 menopausal women over eight weeks 6. The chasteberry group showed significant reductions in anxiety symptoms and vasomotor complaints (hot flushes) compared to placebo. However, there were no significant differences in depression scores, physical symptoms, or sexual function.

Worth noting: This is much thinner evidence than we have for PMS—just one small trial. Other supplements like soy isoflavones and black cohosh have more research behind them for menopause specifically. Chasteberry might be worth considering, particularly for anxiety-predominant symptoms, but I’d want more studies before feeling confident about it. You can find more options in our article on supplements for women’s menopause.

3. Chasteberry May Improve Female Sexual Function

Sexual dysfunction in women is more common than often acknowledged. Problems with desire, arousal, lubrication, orgasm, or pain during intercourse affect quality of life and relationships for many women.

A 2021 randomised, double-blind trial examined chasteberry extract in 112 women of childbearing age over four months 7. Using the Female Sexual Function Index (FSFI), a validated questionnaire, researchers found significant improvements across multiple domains:

Sexual desire
Arousal
Lubrication
Orgasm
Overall satisfaction
Reduced pain during intercourse

Scores improved progressively over the four-month treatment period.

The catch: This is a single study, and sexual function is notoriously difficult to study objectively—placebo effects are substantial when participants are hoping for improvement. The results are interesting but need replication before we can draw firm conclusions. The mechanism also isn’t clear, though it may relate to chasteberry’s effects on prolactin levels, since elevated prolactin can dampen sexual function.

Side Effects of Chasteberry

Chasteberry appears to be reasonably well-tolerated in most studies. The reported side effects are generally mild and infrequent:

Gastrointestinal symptoms: Nausea, stomach upset, diarrhoea
Skin reactions: Itching, rash, allergic dermatitis
Neurological effects: Headache, dizziness, fatigue
Other complaints: Dry mouth, palpitations, increased acne

These side effects occurred in a minority of trial participants, and serious adverse events were rare 1.

However, the safety profile is based primarily on short-term studies (typically 1–3 months). Long-term safety data is limited. Given that chasteberry affects hormone-related pathways, caution is warranted with extended use.

Safety Precautions (5 Contraindications)

1. Avoid if taking hormonal contraceptives or hormone replacement therapy

Chasteberry may interact with oestrogen-containing medications. Because it appears to influence hormonal pathways—potentially affecting oestrogen and progesterone balance—it could theoretically reduce the effectiveness of birth control pills or interfere with hormone replacement therapy. Until we know more, it’s best to avoid combining them.

2. Avoid if taking dopamine-affecting medications

Since chasteberry appears to work partly through dopamine pathways, it could interact with medications that also affect dopamine levels. This includes drugs prescribed for:

Parkinson’s disease (levodopa, pramipexole, ropinirole, rotigotine)
Hyperprolactinaemia (bromocriptine, cabergoline)
Certain psychiatric conditions
Restless leg syndrome

Combining chasteberry with these medications could either enhance or reduce their effects in unpredictable ways.

3. Avoid if you have hormone-sensitive conditions

Because chasteberry may influence oestrogen and progesterone levels, women with hormone-sensitive conditions should avoid it. These include:

Endometriosis
Uterine fibroids
Breast cancer (current or history)
Ovarian cancer
Uterine cancer

The hormonal effects could theoretically worsen these conditions, though this hasn’t been directly studied.

4. Avoid during pregnancy and breastfeeding

Chasteberry’s hormonal effects make it risky during pregnancy and lactation. There’s concern it could affect foetal development or interfere with milk production. The German Commission E explicitly recommends against use during pregnancy 1. No safety data exists for breastfeeding women, so avoidance is prudent.

5. Avoid if you have liver or kidney disease

Like many herbal supplements, chasteberry is processed by the liver and kidneys. Without adequate safety studies in people with impaired organ function, those with liver or kidney disease should probably avoid chasteberry or at minimum consult their doctor before use.

Dosage Considerations

There’s no universally agreed-upon dose for chasteberry, and products vary considerably in their composition. Most clinical trials have used standardised extracts providing:

Dried fruit equivalent: 30–40 mg daily
Standardised extracts: Typically standardised to contain specific amounts of casticin or agnuside

The German Commission E recommends 30–40 mg of dried fruit equivalent daily 1.

If you’re considering chasteberry, look for products that specify what they’re standardised to, and start at the lower end of dosing recommendations. Effects may take several weeks to become apparent—most studies showed benefits after 1–3 menstrual cycles of continuous use.

Summary

Chasteberry has reasonable evidence supporting its use for premenstrual syndrome, particularly for breast tenderness and mood-related symptoms. The evidence for menopausal symptoms and sexual dysfunction is more preliminary—interesting but not yet convincing.

The supplement appears generally safe for short-term use in healthy women, but the list of contraindications is substantial. Women taking hormonal medications, those with hormone-sensitive conditions, and pregnant or breastfeeding women should avoid it.

If you’re considering chasteberry for PMS, it’s probably worth a trial—but give it at least two to three cycles before judging whether it’s helping, and be realistic about expectations. For menopause, you might find more robust evidence supporting evening primrose oil or other options.

References

Wuttke W, et al. (2003). Chaste tree (Vitex agnus-castus)—pharmacology and clinical indications. Phytomedicine, 10(4):348-57. PubMed
Meier B, et al. (2000). Pharmacological activities of Vitex agnus-castus extracts in vitro. Phytomedicine, 7(5):373-81. PubMed
Jarry H, et al. (2003). In vitro prolactin but not LH and FSH release is inhibited by compounds in extracts of Agnus castus. Experimental and Clinical Endocrinology & Diabetes, 102(6):448-54. PubMed
Verkaik S, et al. (2017). The treatment of premenstrual syndrome with preparations of Vitex agnus castus: a systematic review and meta-analysis. American Journal of Obstetrics and Gynecology, 217(2):150-166. PubMed
Lauritzen C, et al. (1997). Treatment of premenstrual tension syndrome with Vitex agnus castus: Controlled, double-blind study versus pyridoxine. Phytomedicine, 4(3):183-9. PubMed
Naseri R, et al. (2019). Comparison of Vitex agnus-castus extracts with placebo in reducing menopausal symptoms: A randomized double-blind study. Korean Journal of Family Medicine, 40(6):362-367. PMC
Bahrami A, et al. (2021). The effect of Vitex agnus-castus extract on female sexual function: a randomized, double-blind, placebo-controlled clinical trial. Journal of Ethnopharmacology, 281:114561. PMC