Also known as: chasteberry, chaste tree, monk's pepper, agnus castus
European herb with strong evidence for PMS and breast pain. Works through dopamine pathways to reduce prolactin - effects build over 3 months. Not a quick fix, but remarkably effective for the right person.
Used for:PMSbreast painirregular cycleshormonal balance
Traditional Use
Traditions: European herbalism, German phytotherapy, Monastic medicine
Multiple traditions agree on use.
Historical Attributions
Used for 'women's complaints,' menstrual irregularities, and breast tenderness. Name 'monk's pepper' suggests historical use in monasteries, possibly to reduce libido.
Approved for PMS, mastalgia, menstrual irregularities, and menopausal disorders. Considered 'long-term hormonal balancing herb' requiring several months of use.
Official monograph establishes quality standards - minimum 0.08% casticin in dried fruit. Reflects long-standing medicinal use in Europe.
Evidence
Vitex has strong evidence for PMS and cyclic breast pain, with effect sizes comparable to pharmaceutical treatments but fewer side effects. Works by activating dopamine receptors to reduce prolactin - a hormonal mechanism that takes 3 months to fully express. Meta-analyses show 2.57x more likely to achieve symptom remission vs placebo. Not for everyone, but when it works, it works consistently.
Key Studies
Meta-analysis: PMS Symptom Remission (2019)
2.57x more likely to achieve symptom remission vs placebo (3 RCTs, n=520, p<0.001). Ze 440 and BNO 1095 standardized extracts.
Cyclic Mastalgia Meta-Analysis (2020)
Moderate effect size SMD 0.67 (p<0.05) across 6 studies, n=718. Pain reduced 33.7mm vs 20.3mm placebo after 2 cycles.
PMS Dose-Finding Study (2012)
20mg Ze 440 optimal dose (n=162). Better than 8mg, equal to 30mg. 52% responder rate vs 24% placebo.
Japanese Population Trial (2014)
91% responder rate by cycle 3 (n=69). Significant improvement from first cycle, continued improvement through month 3.
Most studied preparations. Look for 0.6% casticin standardization. Ze 440 has strongest dose-finding evidence (20mg optimal). BNO 1095 (also called Agnucaston/Cyclodynon) uses 70% ethanol extraction.
tincture — 40 drops once daily (standard) | 2 × 30 drops daily (for breast pain)
Traditional preparation. 50-70% alcohol extraction. Should be standardized to 0.6% casticin. Bitter taste. 40 drops ≈ 1.6-2mL, equivalent to 30-40mg standardized extract.
tea — Not recommended
Water doesn't extract the lipophilic diterpenes (active compounds) effectively. Use alcohol-based extracts or standardized capsules instead.
What The Evidence Says
Vitex has remarkably strong evidence for two specific conditions: premenstrual syndrome (PMS) and cyclic breast pain (mastalgia). This isn’t based on one or two studies - there are multiple meta-analyses pooling dozens of trials.
Strong evidence (multiple meta-analyses):
PMS symptom remission: A meta-analysis of 3 RCTs with 520 participants found you’re 2.57 times more likely to achieve symptom remission compared to placebo [1]
Cyclic breast pain: Meta-analysis of 6 studies (n=718) shows moderate effect size (SMD 0.67, p<0.05). In one trial, pain reduced 33.7mm on visual analog scale vs 20.3mm placebo after 2 cycles (p=0.006) [2]
Responder rates: 52% in placebo-controlled PMS trial vs 24% placebo [3]. Japanese population trial showed 91% responder rate by cycle 3 [4]
Comparison to pharmaceuticals: Seven trials demonstrated vitex as noninferior alternative to dopamine agonists, NSAIDs, SSRIs, and hormonal contraceptives for mastalgia - but with fewer side effects [2]
Moderate evidence:
Hyperprolactinemia: Small RCTs show prolactin reduction comparable to bromocriptine but with better tolerability. In one 3-month trial with 52 women, prolactin release reduced, shortened luteal phases normalized, and 2 women became pregnant during treatment [5]
PMDD: One trial showed 57.9% response rate vs 68.4% for fluoxetine (not significantly different). Vitex better for physical symptoms, fluoxetine better for psychological symptoms [5]
Menopausal symptoms: One 8-week trial (n=52) showed reduced anxiety and vasomotor symptoms (hot flashes), but no effect on depression or sexual dysfunction [5]
Not effective:
Heavy menstrual bleeding: Meta-analysis found no significant effect on bleeding volume compared to placebo [2]
How it works: Diterpenes in vitex activate dopamine D2 receptors in the pituitary, suppressing prolactin secretion. Lower prolactin allows normal progesterone synthesis and luteal phase function. This mechanism has been demonstrated in multiple pharmacological studies with specific EC50 values for active compounds (3-epi-maslinic acid: 5.1 µM, viteagnusin I: 6.6 µM) [5].
Critical nuance: Effects build over 3 months. You may notice some improvement after the first cycle, but full benefits don’t appear until cycle 3. This is a hormonal rebalancing herb, not acute symptom relief.
Traditional Use
European herbalism (centuries):
Primary traditional use: “Women’s complaints” - menstrual irregularities, PMS, breast tenderness
Considered a hormonal balancing tonic requiring long-term use
Traditional preparations: dried fruit, alcohol tinctures
Monastic medicine:
Common name “monk’s pepper” reflects historical use in European monasteries
Believed to reduce libido and promote chastity (though modern evidence shows it works through prolactin, not direct libido suppression)
Reflects medieval monastic herbal knowledge
German phytotherapy tradition:
Strong modern tradition of standardized vitex extracts
German Commission E approved pre-2000 for PMS, mastalgia, menstrual irregularities, menopausal disorders
Philosophy: “Long-term hormonal balancing herb rather than fast-acting remedy”
These names reflect traditional beliefs about effects on sexuality and purity
The convergence is notable: European traditional use for PMS and breast pain, validated by modern double-blind RCTs showing you’re 2.57 times more likely to achieve remission [1]. When tradition and science align this strongly, it’s worth paying attention.
How To Try It
Choose Your Preparation
Standardized extracts (most convenient, most studied):
Three main types - choose based on evidence and availability:
Extract
Standardization
Evidence
Dose
Ze 440
60% ethanol, 6-12:1 ratio
Dose-finding study, multiple RCTs
20mg/day
BNO 1095
70% ethanol, 10:1 ratio
Meta-analysis inclusion
4mg/day
Generic
0.6% casticin or agnuside
Commission E standard
30-40mg/day
For PMS: Ze 440 20mg once daily in morning (strongest dose-finding evidence - 20mg better than 8mg, no benefit from 30mg) [3]
For breast pain: 30-40mg daily OR 60 drops tincture (divided as 30 drops twice daily) [2]
Generic standardized: 30-40mg once daily (Commission E recommendation)
What to look for: 0.6% casticin OR 0.6% agnuside standardization. 50-70% ethanol extraction. Medicinal-grade products with third-party testing.
Tincture (traditional, effective if properly standardized):
All clinical trials used daily dosing, not luteal-phase-only
Effects build over time with consistent levels
Timeline Expectations
Week 1-4 (Cycle 1): Some women notice initial improvement in PMS symptoms. In the Japanese trial, 69 women showed statistically significant decrease in symptom scores after first cycle (p<0.001) [4]. Others notice nothing yet. Both are normal.
Week 5-8 (Cycle 2): Improvements typically become more apparent. In one breast pain trial with 97 women, pain reduced 33.7mm vs 20.3mm placebo by cycle 2 (p=0.006) [2]. Mood symptoms may stabilize.
Week 9-12 (Cycle 3): Full effects emerge. 91% responder rate by this point in one trial [4]. This is when you assess whether it’s working.
After 3 months: If working, continue. If no improvement, reassess - you may be a non-responder.
Don’t expect immediate results. Effects build gradually through prolactin reduction and hormonal rebalancing.
What To Track
Baseline (1 month before starting):
Daily PMS symptom severity (1-10 scale or tracking app)
Breast tenderness rating (1-10 if this is your concern)
Menstrual cycle length and regularity
Specific symptoms: irritability, anxiety, bloating, headaches, fatigue
During trial (months 1-3):
Track the same markers daily. Compare:
Baseline month vs. Cycle 1 vs. Cycle 2 vs. Cycle 3
Focus on week before period (luteal phase symptoms)
Note any changes in cycle length, flow, cramping
What improvement looks like:
“Irritability and mood swings the week before my period basically disappeared”
“Breast tenderness reduced from 8/10 to 2/10 by month 3”
“PMS symptoms went from debilitating to barely noticeable”
“Cycles became regular for the first time in years”
RED FLAGS - Stop and consult provider:
Unexpected absence of period (amenorrhea)
Severe GI distress (beyond mild nausea)
Allergic reaction (rash, itching, swelling)
Pregnancy suspected (discontinue immediately)
Significant worsening of symptoms
Who This Is/Isn’t For
Strong Responders (likely to benefit):
PMS with mood symptoms (irritability, anxiety, depression in luteal phase)
Cyclic breast pain (mastalgia) timed with menstrual cycle
What they report: “It changed my life,” “PMS basically disappeared,” “Breast pain went from unbearable to barely noticeable,” “Cycles regulated after years of irregularity.”
Non-Responders (minimal to no effect):
Normal baseline hormones (if your cycles and hormones are already optimal, vitex won’t improve them)
Heavy menstrual bleeding (meta-analysis shows no effect [2])
Depression unrelated to menstrual cycle
“Hard non-responders” (genetic/individual variation - some just don’t respond)
What they report: “Didn’t notice any difference after 3 months,” “Made GI symptoms worse without helping PMS.”
Action: If no improvement after 3 full cycles, vitex isn’t working for your particular hormonal pattern. Consider other approaches.
Pregnant or trying to conceive: Insufficient safety data, potential uterine stimulant, may affect pregnancy maintenance
Breastfeeding: Will reduce milk supply (prolactin suppression is the mechanism)
Liver disease: Animal studies showed liver toxicity at high doses; use discouraged in preexisting liver disease [5]
On antipsychotics or metoclopramide: May interfere with dopamine antagonist medications
Hormonal birth control users: May theoretically interfere with effectiveness (theoretical, not documented)
Mild adverse events: Survey of 1,634 women found adverse events in only 1.2%, none serious [5]. Most common: mild nausea, headache, GI upset. If persistent GI symptoms occur, discontinue.
The Bitter Taste
Vitex tinctures taste bitter - this is normal. The active diterpenes are extracted in alcohol, and they’re not pleasant. If you’re using tincture (40-60 drops daily), expect a strong, medicinal, bitter flavor.
Standardized capsules avoid the taste entirely and are what most clinical trials use. If taste is a barrier, capsules work just as well - the Ze 440 and BNO 1095 extracts in capsule form have the strongest clinical evidence.
Quality Matters (Non-Negotiable)
The problem: A 2019 quality assessment tested 11 vitex products. Results:
2 of 10 dietary supplements: Marker compounds (casticin/agnuside) not detected at all
1 supplement: Possible contamination with Vitex negundo (different species)
2 supplements: Poor disintegration (pills don’t break down to release actives)
“Proprietary blend” without specific casticin/agnuside content
Very low price (suggests poor raw material)
Dietary supplements without third-party testing
No extraction ratio or solvent information
Why this matters: If your product doesn’t contain the active compounds, it won’t work. Quality variability is real - choose medicinal-grade products only.
The Bottom Line
This is a slow-acting, hormonal-rebalancing herb that works profoundly for some women and does nothing for others. The only way to know is a proper 3-month trial with close tracking.
When it works: Life-changing PMS relief, dramatic breast pain reduction, cycle regulation, hormonal balance. You’re 2.57 times more likely to achieve symptom remission vs placebo [1]. Effects comparable to pharmaceuticals but with better safety profile [2].
When it doesn’t: You’re a non-responder. This is valuable information - try different approaches. Not everyone has elevated prolactin or luteal phase defects.
When it causes problems: Serious contraindications exist (pregnancy, breastfeeding, liver disease). Respect them absolutely. Mild GI symptoms possible in 1.2% of users [5] - discontinue if persistent.
Realistic expectations: Don’t expect results in week 1. Some improvement may appear in cycle 1 (91 women showed significant symptom decrease after first cycle, p<0.001 [4]), but full effects take 3 months. If nothing has changed by cycle 3, it’s not working for you.
Commitment required: Daily dosing for 3 months minimum. Daily symptom tracking to notice subtle changes. Quality product investment (cheap dietary supplements may be ineffective [5]).
Start with standard dose (20mg Ze 440 or 30-40mg generic), take continuously every morning, track symptoms daily, respect contraindications, give it 3 full cycles before deciding. If it works, you’ll know. If it doesn’t, move on.
Trying It
Duration: Minimum 3 menstrual cycles (3 months). Effects begin after 1 cycle but optimal response by cycle 3. If no improvement after 3 cycles, reassess - you may not be a responder.
What to notice:
PMS symptom severity (track daily, especially week before period)
Breast tenderness (rate 1-10 daily if this is your concern)
Mood changes in luteal phase (irritability, anxiety, depression)
Bloating and water retention patterns
Any GI symptoms (nausea, stomach upset - mild but possible)
Start with standard dose: 20mg Ze 440 OR 30-40mg generic standardized extract OR 40 drops tincture. Take once in morning with liquid, continuously (not just during luteal phase). Effects build gradually - month 1 may show some improvement, month 2 solidifies, month 3 reaches full benefit. Track symptoms daily to notice subtle changes. This isn't caffeine or ibuprofen - don't expect immediate relief. If you notice mild GI upset initially, take with food. If no improvement after 3 full cycles, vitex may not work for your particular hormonal pattern.
Combinations
dong quai — Traditional pairing for menstrual irregularities and PMS. Both support female reproductive health through different mechanisms.
black cohosh — For menopausal symptoms - vitex helps with anxiety and hot flashes, black cohosh with vasomotor symptoms. Complementary actions.
cramp bark — For menstrual cramping with PMS. Vitex addresses hormonal pattern, cramp bark provides acute relief.
Safety
Generally considered: safe
Contraindications:
Pregnancy - ABSOLUTE: Lack of safety data, potential uterine stimulant effects, may affect prolactin needed for pregnancy maintenance
Breastfeeding - ABSOLUTE: Prolactin suppression will reduce milk production (this is the mechanism of action)
Liver disease (current or history) - Use discouraged, animal studies showed liver toxicity in repeat-dose studies
On dopaminergic antagonists (antipsychotics, metoclopramide) - Theoretical interaction, may reduce effectiveness of medications
Pregnancy/Nursing: Contraindicated in pregnancy (insufficient safety data, theoretical uterine stimulant activity). Absolutely contraindicated in breastfeeding - will interfere with milk production via prolactin suppression.
Generally safe for healthy non-pregnant women. Adverse events mild and reversible: nausea, headache, GI disturbances (1.2% rate in survey of 1,634 women, none serious). No documented drug interactions in systematic reviews, but theoretical concerns with dopamine antagonists and hormonal contraceptives. Discontinue if pregnancy suspected. May interfere with birth control pills (theoretical). Quality matters: 2 of 10 dietary supplements tested had no marker compounds detected, one possibly contaminated with different Vitex species - choose medicinal-grade standardized products only.