What is Chaste Tree?
Chaste Tree, scientifically known as Vitex agnus-castus, is a flowering shrub native to the Mediterranean and Central Asia regions. Also called chasteberry, monk's pepper, or vitex, this herb has been used for thousands of years in traditional medicine.
The name "chaste tree" comes from historical use by monks who believed it helped reduce sexual desire, promoting celibacy. The medicinal parts are primarily the dried fruit (berries) and sometimes the leaves.
Active Compounds
Chaste tree contains several bioactive components:
Diterpenes: Including clerodadienols (primary active compounds with dopaminergic properties)
Flavonoids: Kaempferol, quercetagetin, casticin
Iridoid glycosides: Agnuside and aucubin
Essential oils
Fatty acids: Including linoleic acid
Trace hormones: Progesterone, testosterone (in very small amounts)
Primary Functions & Benefits
Mechanism of Action:
Chaste tree works primarily through dopaminergic activity at the pituitary gland, which:
Reduces prolactin secretion
Modulates luteinizing hormone (LH) and follicle-stimulating hormone (FSH)
Indirectly increases progesterone production
Helps normalize the ratio of progesterone to estrogen
Evidence-Based Benefits:
Strong Evidence For:
Premenstrual Syndrome (PMS): Reduces breast pain/tenderness, mood swings, irritability, headaches, and anxiety
Cyclic Mastalgia: Relieves menstrual-related breast pain (may be as effective as prescription medications with fewer side effects)
Premenstrual Dysphoric Disorder (PMDD): Comparable effectiveness to fluoxetine (Prozac) for some symptoms
Moderate Evidence For:
Menstrual Irregularities: Helps regulate cycle length and improve cycle predictability
Luteal Phase Deficiency: Increases progesterone during the luteal phase
Fertility Support: May improve fertility in cases of luteal insufficiency or hyperprolactinemia
Hyperprolactinemia: Lowers elevated prolactin levels
Limited/Preliminary Evidence For:
Menopause symptom relief (hot flashes, night sweats)
Acne (hormone-related)
Uterine fibroids
Endometriosis symptoms
Post-birth control pill hormone regulation
Recommended Dosages
Standard Therapeutic Doses:
PMS/General Use: 20-40 mg standardized extract daily
PMDD: 20-40 mg daily
Crude Dried Fruit: 400-1000 mg daily
Liquid Extract/Tincture: 40 drops (approximately 2-4 mL) daily
Fertility Support: 500-1000 mg daily
Important Dosage Notes:
Higher is NOT better: Excessive doses may actually worsen symptoms or cause side effects
Most clinical studies use 20-40 mg of standardized extract
Effects typically require 3 months of consistent use to appear
Continue throughout entire menstrual cycle (not just during symptoms)
Forms Available
Capsules/Tablets: Most common, standardized extracts
Tinctures: Liquid alcohol-based extracts
Liquid Extracts: Alcohol-free options available
Powder: Raw dried berry powder
Tea: Less concentrated, less commonly used therapeutically
Timing & Administration
Best Time to Take:
Morning: Most commonly recommended (single daily dose)
Take at the same time each day for consistency
Best taken as a single dose rather than divided throughout the day
With or Without Food:
Can be taken with or without food
If experiencing nausea, take with food
Some formulations include ginger to prevent stomach upset
Taking with water or food doesn't significantly affect absorption
Duration of Use:
Minimum: 3 months to see full effects
Safe duration: Up to 3 months is well-documented as safe
Many practitioners recommend 3-6 months for fertility or cycle regulation
Long-term safety (beyond 3 months) is less well-studied but appears safe for most people
Synergistic Supplements
Can Be Combined With:
Magnesium: Supports hormonal balance and reduces PMS symptoms
Vitamin B6 (Pyridoxine): Studies show similar effectiveness to vitex for PMS; may work synergistically
Evening Primrose Oil: For breast pain and PMS
St. John's Wort: Some studies combine these for menopausal symptoms (use with caution)
Black Cohosh: For menopause support
Omega-3 Fatty Acids: Anti-inflammatory support for menstrual health
Calcium and Vitamin D: For PMS and overall hormonal health
Fertility-Specific Combinations:
Green tea extract
L-arginine
Maca root
CoQ10
Interactions & What NOT to Take
Medications to Avoid or Use with Caution:
Dopamine Antagonists (may reduce vitex effectiveness):
Antipsychotics: Haloperidol, chlorpromazine, risperidone, olanzapine, quetiapine, aripiprazole
Anti-nausea medications: Metoclopramide, prochlorperazine
Dopamine Agonists (may enhance effects/risks):
Bromocriptine (Parlodel) - used for hyperprolactinemia
Levodopa (Parkinson's medication)
Cabergoline
Hormone-Related Medications:
Birth control pills (may reduce contraceptive effectiveness)
Hormone replacement therapy (HRT)
Fertility medications
Anti-estrogen drugs
Other Considerations:
May interfere with Parkinson's disease medications
Use caution with antidepressants (especially if also taking St. John's Wort)
Substances to Avoid:
Avoid during pregnancy (may stimulate uterine contractions or affect hormones)
High-dose vitex while breastfeeding (doses above 200 mg may reduce milk supply due to prolactin-lowering effects)
Who Should Take Chaste Tree
Ideal Candidates:
Women with regular PMS or PMDD symptoms
Those experiencing cyclic breast pain
Women with irregular menstrual cycles
Those with luteal phase deficiency
Women with hyperprolactinemia
Those experiencing infertility related to hormonal imbalances
Women transitioning off hormonal birth control
Post-pill amenorrhea (missing periods after stopping birth control)
Those with estrogen dominance symptoms
Women with hormone-related acne
Perimenopausal women (with caution and medical supervision)
Age Groups:
Primarily adult women of reproductive age
Can be used by perimenopausal women
Not typically recommended for post-menopausal women
Who Should AVOID or Use Caution
Absolute Contraindications:
Pregnant women: May affect pregnancy hormones or cause uterine stimulation
Women actively breastfeeding: High doses can reduce milk production
Hormone-sensitive cancers: Breast, uterine, ovarian cancer (current or history)
Children and adolescents: Safety not established
People with pituitary disorders: Including prolactinomas
Use with Medical Supervision:
Women on birth control: May reduce contraceptive effectiveness
Those taking fertility medications: Requires medical oversight
People with Parkinson's disease: May interfere with medications
Those with mental health conditions: Especially if on antipsychotic medications
IVF candidates: Consult reproductive endocrinologist first
Anyone taking hormone-affecting medications
Conditions Requiring Caution:
Endometriosis (mixed evidence)
Polycystic ovary syndrome (PCOS) - may help some but consult doctor
History of depression or psychiatric disorders
Schizophrenia or psychotic disorders (due to dopamine effects)
Side Effects & Safety Profile
Common Mild Side Effects (generally rare):
Nausea or upset stomach
Headache
Dizziness
Fatigue or insomnia
Gastrointestinal disturbances
Diarrhea
Mild acne or skin rash
Itching (pruritus)
Changes in menstrual flow (usually temporary)
Weight changes (rare)
Rare but Serious Side Effects:
Allergic reactions
Severe skin reactions (Stevens-Johnson syndrome - extremely rare)
Hepatitis (one case report)
Significant menstrual changes
Overall Safety:
Generally considered very safe for short-term use (up to 3 months)
Adverse events occur in approximately 1% of users
Most side effects are mild and reversible
No significant drug interactions have been formally documented in clinical trials
Long-term safety (beyond 3 months) less well-studied but appears safe
Effects on Hormones & Deficiency/Excess
Hormonal Effects:
Chaste tree doesn't contain hormones but affects their production:
Decreases:
Prolactin levels (primary effect)
Relative estrogen dominance
Increases:
Progesterone (indirectly, by supporting corpus luteum function)
LH and FSH normalization
Balances:
Progesterone-to-estrogen ratio
"Deficiency" Symptoms (Conditions Vitex May Help):
Since vitex is an herb (not an essential nutrient), there's no true deficiency. However, it may help with symptoms of:
Low progesterone: Short luteal phase, spotting before period, difficulty conceiving
High prolactin: Irregular or absent periods, breast discharge, reduced fertility
Estrogen dominance: Heavy periods, breast tenderness, PMS, mood swings
Menstrual irregularity: Unpredictable cycles, absent periods (post-pill)
"Excess" Symptoms (Potential Side Effects of Too Much):
Excessive menstrual bleeding
Disrupted menstrual cycle
Ovarian hyperstimulation (rare)
Reduced milk supply (in nursing mothers)
Increased side effects (nausea, headache, dizziness)
Worsening of symptoms it's meant to treat
Toxic Dose: Not well-established, but doses significantly above 40-60 mg daily increase risk of side effects without improving benefits
Special Populations & Considerations
Fertility & Conception:
May help restore ovulation and regulate cycles
Studies show increased pregnancy rates in women with luteal insufficiency
Should be discontinued once pregnancy is confirmed
Some herbalists use it in early pregnancy for luteal support, but safety is not established
Always consult a fertility specialist before combining with fertility treatments
Postpartum & Breastfeeding:
Low doses (under 200 mg) may support milk production
Higher doses can reduce milk supply due to prolactin-lowering effects
Generally recommended to avoid during active breastfeeding
Not recommended for treating mastitis
Post-Birth Control Use:
Particularly helpful for regulating cycles after stopping hormonal birth control
May speed up return of regular ovulation
Useful for "post-pill amenorrhea"
Typically takes 3-6 months to see full effects
Menopause/Perimenopause:
Limited evidence for effectiveness
May help some women with hot flashes and mood changes
More research needed
Should be used under medical supervision
Comparison to Prescription Medications
Vitex vs. Bromocriptine (for hyperprolactinemia):
Similar prolactin-lowering effects
Vitex has fewer side effects
Bromocriptine works faster but has more adverse effects
Vitex requires longer treatment (3+ months)
Vitex vs. Fluoxetine (for PMDD):
Comparable effectiveness for some PMDD symptoms
Different mechanism of action
Vitex may be preferred by those seeking natural alternatives
Antidepressants work faster (weeks vs. months)
Vitex vs. Prescription Pain Medications (for mastalgia):
Similar effectiveness for cyclic breast pain
Fewer side effects than prescription options
Requires consistent daily use (not as-needed)
Clinical Evidence Quality
High-Quality Evidence:
PMS symptom reduction (multiple RCTs)
Cyclic mastalgia relief (controlled trials)
Moderate Evidence:
Menstrual regulation
Hyperprolactinemia
Low/Preliminary Evidence:
Fertility enhancement
Menopause symptoms
Acne treatment
Endometriosis
Note: Some recent systematic reviews suggest benefits may be somewhat overestimated, but most agree it has mild-to-moderate effectiveness with excellent safety profile.
Liver Safety
Oral forms of chaste tree have not been implicated in significant liver enzyme elevations or clinically apparent liver injury. One isolated case of hepatitis with jaundice was reported but is extremely rare. Vitex is generally considered safe for the liver, though those with pre-existing liver disease should use caution.
Summary & Key Takeaways
Chaste tree (Vitex agnus-castus) is a well-tolerated herbal remedy primarily used for women's reproductive health. It works through dopaminergic activity to lower prolactin and indirectly support progesterone production.
Best For:
PMS and PMDD symptoms
Menstrual-related breast pain
Irregular cycles
Post-pill hormone regulation
Luteal phase deficiency
Key Guidelines:
Take 20-40 mg daily in the morning
Requires 3+ months for full effects
Can be taken with or without food
Safe for most women of reproductive age
Avoid during pregnancy and high doses while breastfeeding
Contraindicated for hormone-sensitive cancers
Bottom Line: Chaste tree is a safe, evidence-based option for hormonal balance with minimal side effects. It's most effective for PMS and cycle regulation when used consistently for at least 3 months. Always consult a healthcare provider before use, especially if taking medications or trying to conceive.