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Vitex agnus-castus (Chasteberry)
Well-studied herb for premenstrual syndrome and cyclic breast pain, with supportive RCT evidence for PMS symptom relief.
What the evidence says
Vitex doesn't have enough studies with structured effect-size data yet to pool a verdict. Browse the studies below for individual findings.
Most evidence is from high-quality meta-analyses and randomised trials published 1998–2026 with a typical study size of 96 participants.
Based on 54 studies · 5 meta-analyses · 24 RCTs · 1,750 total participants
Confidence
High confidenceWhat the studies found
By outcome
Multiple meta-analyses of randomized trials show Vitex consistently reduces PMS and cyclic mastalgia symptoms, but most trials carry unclear-to-high risk of bias, capping it below the top tier.
12 randomised trials
every one checked individually
Every randomised or controlled trial of Vitex indexed in PubMed, not a hand-picked subset. Meta-analyses and systematic reviews are deliberately excluded from this count: most of them cover many compounds at once, so counting them would inflate it.
PubMed · as of Jul 2026
No trials currently enrolling · 5 completed on ClinicalTrials.gov
Registered trials show research momentum for Vitex, not proof of effect — a registration is a plan, and posted results are sponsor-reported, not peer-reviewed. They are never counted toward the evidence rating above.
Browse these trials on ClinicalTrials.govClinicalTrials.gov · as of Oct 2026
Vitex, also known as chasteberry, is an herb used for premenstrual complaints. It acts on the pituitary, binding dopamine receptors to lower prolactin.
The strongest clinical evidence — randomized trials and meta-analyses — supports its use for premenstrual syndrome (PMS) and cyclic breast pain (mastalgia), though most trials carry an unclear or high risk of bias and the pooled effects should be read cautiously.
Evidence for menstrual-cycle regulation and fertility is weaker and largely inconclusive.
Acts on dopamine receptors in the pituitary
Acts on dopamine receptors and lowers prolactin in some studies. An estrogen-progesterone "balance" has not been measured
How Vitex works — from molecular targets to health outcomes. Click an edge to see supporting research.This visualization is in beta — pathways are being refined and expanded.
Discontinue once pregnancy confirmed
Expert opinion conflicts on whether vitex raises or lowers milk supply, and safety while breastfeeding is not established. Avoid unsupervised use and ask a clinician first
Often used to support fertility; discontinue upon pregnancy
Theoretical. The EU herbal monograph reports no interactions and says interactions with oestrogens cannot be excluded. It does not name hormonal contraceptives, and no study has measured contraceptive failure with vitex
May interact due to dopaminergic activity
May alter hormone levels
May interfere with protocols
Tip: Take with food if needed
Tip: Usually resolves
Tip: Discontinue if rash occurs
Tip: Normal during adjustment; give 2-3 cycles
Vitex has an evidence score of 7/10 — strong evidence based on 53 indexed studies, including 5 meta-analyses. Well-studied herb for premenstrual syndrome and cyclic breast pain, with supportive RCT evidence for PMS symptom relief. Representative study: PMID 31780016.
The commonly studied dose of Vitex is 20-40mg extract (standardized to 0.5% agnuside). The cited trials used 20 to 30 mg of extract a day. Research points to an estimated optimal dose around 20mg extract, with a minimum effective dose near 20mg extract. Individual response varies — start low and adjust.
The best time to take Vitex is in the morning. Taking it with food is preferred. Vitex agnus-castus (chasteberry) acts on the hypothalamic-pituitary axis by binding dopamine D2 receptors in the anterior pituitary, reducing prolactin secretion.
Vitex has a safety rating of "moderate". That is a category, not a measure of individual risk, and there are precautions worth knowing. The most commonly reported side effects are cycle changes initially, GI upset, headache. Use caution if any of these apply to you: Pregnancy (discontinue when pregnant); Hormone-sensitive conditions (breast cancer, etc.); IVF or fertility treatments (may interfere).
Vitamin D3
Probably helpsHormone-like vitamin that regulates 1,000+ genes — deficiency is widespread and linked to poor immunity, depression, and bone loss.
St. John's Wort
Likely helpsModulates serotonin, dopamine, and norepinephrine; studied for mood, with trials in mild-to-moderate depression comparing it to SSRIs — requires drug-interaction caution.
Ashwagandha
Likely helpsReduces cortisol and anxiety while improving sleep quality and physical recovery in stressed adults.
Curcumin
Probably helpsTurmeric's active compound that modulates NF-kB inflammatory pathways — supports mood, joint health, and post-exercise recovery.
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Reviewed by Dr. Baher Al Hakim · Last reviewed June 2026 · evidence from 54 studies · how we score · editorial policy
This information is for educational purposes only. It is not a substitute for professional medical advice. Always consult a qualified healthcare provider before starting, stopping, or changing any supplement or medication.
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