Cross-referencing clinical data
StrongChaste Tree
Chaste Tree.
The go-to herb for PMS and menstrual irregularities. Works by gently rebalancing prolactin and progesterone. Binds to dopamine D2 receptors in the pituitary, lowering prolactin. This allows progesterone to normalize, correcting the hormonal imbalance behind most PMS symptoms.
StrongResearch strength40mgDaily amount
Reviewed March 2026
- Category
- Herb
- Also filed under
- Reduces PMS symptoms significantlyHelps regulate menstrual cyclesLowers elevated prolactin levels
What Chaste Tree is, and what it does.
- Does it work
- One of the strongest herbal medicines for PMS. Multiple clinical trials with clear results. German Commission E approved. If PMS is your issue, this is a first-line natural option.
- How much to take
- 20-40 mg standardized extract (like Ze 440) per day. Higher doses of crude berry powder: 500-1000 mg.
- The first dose
- Nothing noticeable. Hormonal rebalancing takes weeks to manifest.
- With regular use
- By month 2-3, significant PMS symptom reduction in most women. Full benefit at 3-6 months.
- How well tolerated
- Generally well tolerated. Don't combine with hormonal contraceptives, hormone therapy, or dopamine-affecting medications. Avoid during pregnancy.
- How it feels
- After 2-3 months: less PMS. That might mean fewer mood swings, less breast pain, fewer headaches, and more regular periods. The cumulative effect is genuinely life-improving for many women.
About 40mg a day is the studied dose.
How much to take a dayHigh confidence
Up to 20mgA supporting amount. Helps a little, not the studied dose.
20mg to 40mgEnough for most people, and where a lot of good products land.
40mg
The doseThe daily amount the trials actually used. A product at this figure is dosed right where the research is.
Above 40mgMore capsules, not more effect. Rarely in a serving anyway.
The proof, claim by claim.
These words describe the research, not the molecule's worth. Research strength is how much work stands behind one claim, and it is never a product score.
- Significantly reduces PMS symptoms
- Helps regulate irregular menstrual cycles
- Works through prolactin reduction
PubMedCochraneClinicalTrials.govNIH ODSSUPP.AILabs test. IngredientMD verifies.PubMedCochraneClinicalTrials.govNIH ODSSUPP.AILabs test. IngredientMD verifies.
Questions people ask about Chaste Tree.
- How long until I notice a difference?
- Most women notice improvement after 2-3 menstrual cycles. That means 2-3 months of daily use. Don't give up after one month.
- Can I take this with birth control pills?
- Not recommended. Vitex affects hormonal balance and may interfere with hormonal contraceptive effectiveness. Talk to your doctor.
- Does it help with fertility?
- It may help women with luteal phase deficiency (low progesterone after ovulation). By normalizing progesterone levels, it can improve conditions for conception. But work with a fertility specialist.
- Should I take it every day or just during PMS week?
- Every day, all month long. The hormonal rebalancing requires consistent daily dosing through all cycle phases. It's not an as-needed remedy.
- Can men take this?
- Men generally shouldn't. It lowers prolactin, which affects testosterone production. Unless specifically recommended by a healthcare provider for elevated prolactin.
- Will this affect my period timing?
- It might. By normalizing hormones, it can shift cycle length toward a more regular pattern. This is usually a positive change, but track your cycle during the first few months.
Nothing to show here, and the reason why.
A pairing appears on this page only when a trial gave both ingredients together and measured the result. Chaste Tree has none that clears that bar.
No pairing for Chaste Tree has cleared review yet.
Stitching two separate single-ingredient studies into a pairing is the one thing this engine will not do. When a study of the combination itself holds up at source, it lands here with its citation.
No invented synergy. Where actives were studied on their own rather than together, the record shows each on its own evidence, never a combined effect no trial measured.
Research strength. Research strength says how much work stands behind the combination. It is never a product score.
Independent record. Every finding is cited to a named trial, dated, and never written by the brand.
20 pairings are live across the library today. Checked 20 July 2026.
Plays well withEstablished knowledge, not a trial
No study gave these as a pair, so they are not in the card above. But the reason they belong together is settled biochemistry, not a guess, so it is worth knowing.
Chaste Tree + Vitamin B6 (Pyridoxine)cofactor for dopamine synthesis
B6 as pyridoxal-5-phosphate is the cofactor for the decarboxylase step that makes dopamine, and dopamine tone at the pituitary is what sets prolactin output. Vitex acts on that same dopaminergic receptor side.
Chaste Tree + P5P (Pyridoxal-5-Phosphate)active cofactor for dopamine synthesis
P5P is the ready-to-use coenzyme form for aromatic amino acid decarboxylase, the enzyme that produces dopamine. Vitex works on dopamine receptor signalling, so cofactor supply and receptor action line up.
Chaste Tree + Magnesium Glycinatelong-standing cyclical support formulation
Magnesium supports smooth muscle relaxation and works with B6 in neurotransmitter enzymes, a standing pairing with vitex in monthly cycle formulas. The mechanisms are separate and non-competing.
Chaste Tree + Black Cohoshmidlife hormonal formulation practice
Black cohosh acts on serotonergic and central pathways rather than the dopamine and prolactin axis vitex works on. Formulas for midlife hormonal change combine the two for that reason.
Chaste Tree + Dong Quai (Angelica sinensis)traditional women's formula pairing
Dong quai coumarins support circulation and smooth muscle tone while vitex works at the pituitary. They occupy different roles in classic cyclical blends.
Chaste Tree + Evening Primrose Oilprostaglandin pathway complement
Evening primrose GLA feeds the series-1 prostaglandin pathway that governs breast and tissue comfort, a route vitex does not act on. The two are long-standing companions in cyclical formulas.
Chaste Tree + Saffron (Crocus sativus)complementary monoamine mechanism
Saffron crocins act on serotonin reuptake and mood pathways, separate from vitex's dopaminergic effect on prolactin. Cyclical mood formulas pair them for that split.
Chaste Tree + Mucuna Pruriens (Velvet Bean)additive dopaminergic activity
Mucuna supplies L-dopa, a direct dopamine precursor, while vitex acts as a dopamine receptor agonist at the pituitary. Stacking both pushes the same axis from two directions and the combined effect on prolactin can be larger than intended.
Chaste Tree + CalciumEstablished nutrient physiology, common co-formulation
Calcium is a standard component of cycle-support formulas and acts on neuromuscular and smooth-muscle signalling, a different lever from a dopaminergic plant extract. The two are combined for coverage rather than for an interaction. No trial has measured the pair.
Chaste Tree + Vitamin DEstablished cofactor relationship with calcium handling
Vitamin D drives the calcium-binding transport proteins that make intestinal calcium absorption efficient, so it belongs next to any calcium in the same formula. Its relationship is with the mineral, not with the plant extract. Established physiology with no combination data for chaste tree.
Chaste Tree + InositolEstablished second-messenger biochemistry
Myo-inositol and its phosphorylated derivatives are second messengers downstream of several peptide hormone receptors, including gonadotropin signalling in the ovary. Chaste tree acts higher up, at pituitary prolactin release through dopamine receptors. The two touch different points of the same axis and have not been trialled together.
Chaste Tree + ZincEstablished cofactor relationship
Zinc is a cofactor in steroid hormone receptor function, since the classic nuclear receptor DNA-binding domain is a zinc finger. It also supports normal reproductive tissue function generally. This is background physiology rather than a measured effect with the extract.
Chaste Tree + GLA gamma-linolenic acidEstablished eicosanoid biochemistry, common co-formulation
GLA is elongated to dihomo-gamma-linolenic acid, the precursor of series-1 prostaglandins, which is why it appears in cycle-comfort formulas. It works on lipid mediators; chaste tree works on pituitary prolactin release. The stored partner evening primrose oil is the usual GLA source, so a formula should not double the same fatty acid unknowingly.
Chaste Tree + AshwagandhaSeparate established mechanisms, common co-formulation
Ashwagandha withanolides are studied for their effect on the hypothalamic-pituitary-adrenal axis and cortisol output, while chaste tree diterpenes act on dopamine receptors at the pituitary. Both touch pituitary output but at different cell populations and hormones. Combination products exist; combination trials do not.
Chaste Tree + Rhodiola roseaSeparate established mechanisms, common co-formulation
Rhodiola salidrosides and rosavins are studied for stress-axis and monoamine effects; chaste tree is dopaminergic at the pituitary. Because both touch monoamine signalling, the combination is worth flagging as overlapping rather than purely additive. Nothing has been measured together.
Chaste Tree + ChamomileTraditional co-formulation and shared receptor family
Chamomile apigenin binds GABA-A receptors at benzodiazepine-adjacent sites in laboratory work, giving it a calming character. Chaste tree is not sedating, so in a blend chamomile carries that property alone. Stacking several calming botanicals can add up, which matters before driving.
Chaste Tree + Lemon balmTraditional co-formulation and shared receptor family
Lemon balm constituents inhibit GABA transaminase in laboratory assays, which raises GABA availability. It is a common partner in evening cycle-support blends. The additive calming effect with other GABAergic botanicals is the practical consideration, not an interaction with chaste tree itself.
Chaste Tree + St Johns wortEstablished enzyme induction, well-documented
St John's wort hyperforin activates the pregnane X receptor and induces CYP3A4 and P-glycoprotein, which lowers exposure to many co-administered compounds including hormonal contraceptives. That induction is the single most important thing to know about the pairing, whatever the chaste tree does. Anyone on prescription medicine should raise the combination with a clinician before taking it.
Chaste Tree + 5-HTPEstablished monoamine pharmacology
5-HTP is decarboxylated to serotonin by aromatic L-amino acid decarboxylase, the same enzyme that converts L-DOPA to dopamine, so the two substrates compete for it. Chaste tree acts at dopamine receptors rather than on synthesis, but stacking monoamine-active ingredients deserves care and is a reason to involve a clinician if any serotonergic medicine is in play.
Chaste Tree + L-tyrosineEstablished biosynthetic pathway
Tyrosine is hydroxylated to L-DOPA and decarboxylated to dopamine, so it supplies the substrate side of dopaminergic signalling. Chaste tree diterpenes act on the receptor side. Substrate and receptor are complementary points in one pathway, though the pair has not been studied together.
Chaste Tree + IronEstablished nutrient physiology, formulation practice
Menstrual blood loss is the main route of iron loss in menstruating adults, which is why iron sits in cycle-support formulas. It has no pharmacological relationship with chaste tree. Iron absorption is improved by vitamin C and reduced by tea polyphenols and calcium taken in the same dose, so timing matters more than the botanical pairing.
Who should be cautious
Talk to a doctor before taking Chaste Tree if any of these apply to you: Don't use with hormonal contraceptives, Avoid during pregnancy and breastfeeding, Takes 2-3 months for full effect. These are flags to check first, not effects Chaste Tree is known to cause.
Not medical advice. Show the label to your pharmacist.Getting Chaste Tree from food.
The whole-food sources on file. A supplement closes the gap, it does not replace dinner.
No food equivalent
A gram-for-gram figure (how much of each you would eat to match a dose) will appear here once it is sourced and reviewed. This page will not print a number it cannot cite.
The forms it comes in.
Vitex agnus-castus fruit, chaste berryMilled ripe dried fruit, all constituent classes present at their natural ratioFits Traditional preparations and teas, and formulas dosing crude herb by weightTrade-off Constituent content varies with harvest and storage, and no marker is declared, so doses across products are not comparable
Vitex extract standardised to agnuside or casticinEthanol-water extraction concentrated to a powder and assayed against a markerFits Capsules and tablets dosing to a declared marker figureTrade-off The marker is an analytical proxy rather than a demonstrated active, so two extracts matching on agnuside can still differ in diterpene content
Vitex CO2 extractNon-polar extraction that concentrates the lipophilic diterpenes and leaves most water-soluble glycosides behindFits Products targeting the lipophilic fraction specificallyTrade-off Low or absent iridoid glycoside content, so an agnuside specification does not describe it and doses cannot be read across from a hydroethanolic extract
Vitex tinctureBerries macerated in ethanol and water, sold as a liquid at a stated herb-to-liquid ratioFits Practitioner dispensing and flexible dosing by dropsTrade-off Carries ethanol, and the strength is expressed as a ratio rather than a marker assay
What the strongest studies found
The essence, in one line each.
- Dietary Vitex agnus-castus extract was associated with changes in immune and haematological markers in rainbow trout; the authors report immunomodulatory effects in that species.Animal study. Salem MOA et al., 2025 (Open Veterinary Journal). PMID 42376520 ↗
- Extract supplementation was associated with changes in growth performance and haemato-biochemical markers in farmed fish; markers, not clinical outcomes, and the ingredient is one of several discussed.Animal study. Mehrim AI et al., 2026 (Aquaculture Nutrition). PMID 41585321 ↗
These are the studies our verdict leans on, chosen from the 2 we read for Chaste Tree. The full linked list is below.
Problems people have reported.
Read this carefully. These are 10,859 voluntary, unverified reactions reported to the FDA (openFDA). The number mostly reflects how popular Chaste Tree is, not how risky it is. A report is not proof Chaste Tree caused anything. It is a signal of what to watch for, nothing more.
Fatigue
444
Diarrhoea
366
Nausea
336
Headache
314
Dizziness
280
Pain
277
Source: openFDA adverse-event reports. Voluntary reporting, not an incidence rate.
FDA Disclaimer: These statements have not been evaluated by the Food and Drug Administration. This information is for educational purposes only and is not intended to diagnose, treat, cure, or prevent any disease. Consult your healthcare provider before starting any supplement regimen.
