Vitex agnus-castus (chasteberry, monk's pepper)

Herbal preparation for PMS, supplement. In EU – traditional herbal medicinal product (EMA HMPC). AEMPS does not register as medicine

ATC code: A11JA-VITEX (Vitex agnus-castus (chasteberry))

Brand names – supplements

Now Vitex, Solgar Vitex Berry, Gaia Herbs Vitex Berry, Nature's Way Vitex Fruit

Supplements are not tested in clinical trials and are not registered as medications.

Mechanism of action

Vitex fruits contain iridoid glycosides (agnuside, aucubin), flavonoids (casticin), essential oils, diterpenes. In animal models vitex extract is a weak dopamine D2 receptor agonist in the pituitary, reducing prolactin secretion. In women with PMS irregular cycles and cyclic mastodynia may be linked to latent hyperprolactinaemia; prolactin reduction via vitex restores normal luteal phase. HMPC 2018 recognises vitex as a traditional herbal medicinal product for relief of mild PMS symptoms; recommendation based on 30 years of traditional use.

Indications

Premenstrual syndrome

Adjunct

Vitex is one of the few herbal preparations with relatively convincing evidence in premenstrual syndrome (PMS). Csokay 2013 (Planta Med) systematic review of 7 RCTs in 1100 patients: vitex 4-40 mg extract per day × 3 cycles improved PMS questionnaire scores (irritability, mastodynia, headache, mood swings) vs placebo. HMPC 2018 recognises vitex as a traditional herbal medicinal product for mild PMS symptoms. 2014 lists SSRIs (fluoxetine, sertraline), drospirenone-containing combined oral contraceptives and CBT first-line for PMS; for marked mastodynia – topical NSAIDs, spironolactone. Vitex is an additional option for mild PMS symptoms in patients preferring herbal preparation.

Sources

Marketing claims without evidence base

The drug is promoted for these uses outside international guidelines. Each entry below is analyzed against AEMPS, FDA, EMA, Cochrane and major RCTs.

Dysmenorrhea

Not recommended

Chasteberry (Vitex agnus-castus) is a plant extract promoted for menstrual pain and other premenstrual symptoms. For dysmenorrhea it has been studied, but no convincing benefit has shown up: there is no solid evidence base for this use, and the available data come from low-quality studies. For painful periods, NSAIDs (ibuprofen, naproxen) and hormonal contraception have proven effect. Discuss treatment options with your doctor.

Sources

Premenstrual dysphoric disorder (PMDD)

Not recommended

Vitex is sold for PMDD (premenstrual dysphoric disorder) as a «natural antidepressant» promising reduction in irritability, depression and anxiety in luteal phase. Evidence in PMDD (severe PMS form, DSM-5) is weak: RCTs with DRSP (Daily Record of Severity of Problems) and PMDD scale endpoints are minimal. 2014 lists SSRIs (fluoxetine, sertraline) continuously or in luteal phase first-line for PMDD; vitex is not in main international guidelines. If vitex was recommended for PMDD with marked depression, suicidal thoughts or daily-life impairment instead of psychiatric consultation, consider seeking a second opinion.

Sources

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Safety

Contraindications

Pregnancy and lactation (lactation disruption risk via prolactin reduction)
Children and adolescents under 18
Dopamine agonist or antagonist therapy (bromocriptine, cabergoline, metoclopramide, antipsychotics) – competitive interaction risk
Hormone-sensitive breast or endometrial tumours
Pituitary tumours

Serious adverse effects

Allergic reactions up to anaphylaxis (rare)
Lactation disruption in nursing mothers
Interference with dopaminergic therapy (antipsychotics, Parkinson disease)

Common adverse effects

Nausea and abdominal pain
Allergic skin reactions (itch, rash)
Headache
Increased bleeding in first cycles of use

PregnancyFDA N

No RCT data in pregnancy. EMA HMPC 2018 lists pregnancy as contraindication. Avoid in pregnancy – theoretical effect on hypothalamic-pituitary axis via D2 agonism may disrupt endocrine balance.

Breastfeeding

Lactation is contraindication. Vitex reduces prolactin and may theoretically disrupt lactation.

Calculate RID

Reference information, not a clinical decision. Discuss feeding pauses or changes with your physician or an IBCLC.

Frequently asked

What is Vitex agnus-castus (chasteberry, monk's pepper) used for?

Vitex agnus-castus (chasteberry, monk's pepper) is evaluated for the following indications with varying evidence strength: Premenstrual syndrome (evidence tier C), Premenstrual dysphoric disorder (PMDD) (evidence tier D), Dysmenorrhea (evidence tier D). See the full indication matrix with dosing and citations above on this page.

What are the side effects of Vitex agnus-castus (chasteberry, monk's pepper)?

Common side effects of Vitex agnus-castus (chasteberry, monk's pepper) (≥ 1 in 100): Nausea and abdominal pain, Allergic skin reactions (itch, rash), Headache, Increased bleeding in first cycles of use. See the Safety section for uncommon and serious reactions.

Is Vitex agnus-castus (chasteberry, monk's pepper) safe during pregnancy?

FDA category N. No RCT data in pregnancy. EMA HMPC 2018 lists pregnancy as contraindication. Avoid in pregnancy – theoretical effect on hypothalamic-pituitary axis via D2 agonism may disrupt endocrine balance.

Is Vitex agnus-castus (chasteberry, monk's pepper) compatible with breastfeeding?

Lactation is contraindication. Vitex reduces prolactin and may theoretically disrupt lactation.

Who should not take Vitex agnus-castus (chasteberry, monk's pepper)?

Vitex agnus-castus (chasteberry, monk's pepper) is contraindicated in: Pregnancy and lactation (lactation disruption risk via prolactin reduction); Children and adolescents under 18; Dopamine agonist or antagonist therapy (bromocriptine, cabergoline, metoclopramide, antipsychotics) – competitive interaction risk; Hormone-sensitive breast or endometrial tumours; Pituitary tumours. Full list in the Safety section.

Mechanism of action

Indications

Premenstrual syndrome

Adjunct

Sources

Safety

Contraindications

Pregnancy and lactation (lactation disruption risk via prolactin reduction)
Children and adolescents under 18
Dopamine agonist or antagonist therapy (bromocriptine, cabergoline, metoclopramide, antipsychotics) – competitive interaction risk
Hormone-sensitive breast or endometrial tumours
Pituitary tumours

Serious adverse effects

Allergic reactions up to anaphylaxis (rare)
Lactation disruption in nursing mothers
Interference with dopaminergic therapy (antipsychotics, Parkinson disease)

Common adverse effects

Nausea and abdominal pain
Allergic skin reactions (itch, rash)
Headache
Increased bleeding in first cycles of use

PregnancyFDA N

No RCT data in pregnancy. EMA HMPC 2018 lists pregnancy as contraindication. Avoid in pregnancy – theoretical effect on hypothalamic-pituitary axis via D2 agonism may disrupt endocrine balance.

Breastfeeding

Lactation is contraindication. Vitex reduces prolactin and may theoretically disrupt lactation.

Calculate RID

Reference information, not a clinical decision. Discuss feeding pauses or changes with your physician or an IBCLC.

Frequently asked

What is Vitex agnus-castus (chasteberry, monk's pepper) used for?

What are the side effects of Vitex agnus-castus (chasteberry, monk's pepper)?

Is Vitex agnus-castus (chasteberry, monk's pepper) safe during pregnancy?

Is Vitex agnus-castus (chasteberry, monk's pepper) compatible with breastfeeding?

Lactation is contraindication. Vitex reduces prolactin and may theoretically disrupt lactation.

Who should not take Vitex agnus-castus (chasteberry, monk's pepper)?