Does chaste tree work like the contraceptive pill?

No. It has no contraceptive action, and it should not be used with hormonal contraception without practitioner guidance.

Can chaste tree help with fertility?

I have not reviewed the evidence for fertility in enough detail to say. If you are trying to conceive, speak to your GP or a practitioner first, because the EU monograph does not recommend chaste tree in pregnancy.

Is it suitable for menopause?

The monograph's use is for premenstrual symptoms. I have not reviewed the evidence for menopause in enough detail to say.

How long should I take it?

The main trial ran for three cycles. Beyond that I would review with a practitioner.

Are chaste tree, chasteberry and Vitex the same thing?

Yes. They are common names for Vitex agnus-castus, and the berries are the part used.

Can men take chaste tree?

The monograph's use is for premenstrual symptoms in women. I have not reviewed the evidence for men, and Hormone Harmony is formulated with women's health in mind.

Are there side effects?

The reported ones are mostly mild, such as stomach upset, headache, dizziness or skin reactions, and menstrual changes.

Chaste Tree (Vitex): What It Is, How It Works, and When to Use It

Sarah Burt

Oct 14

6 min read

Chaste tree (Vitex agnus-castus), also called Vitex or monk's pepper, is a Mediterranean shrub whose dried berries are among the best-studied herbs in women's health. It is one of the few herbs in this library with a European monograph that recognises a well-established use, in this case for premenstrual symptoms. It is also a herb with real activity in the body, which is why the safety section of this guide matters more than usual. It is one of the four herbs in the EarthWise Hormone Harmony tonic.

What it is

Chaste tree is a deciduous shrub or small tree in the mint family (Lamiaceae), native to the Mediterranean and parts of Central Asia. It grows to a few metres, with hand-shaped leaves made of five to seven narrow leaflets and spikes of lilac flowers in late summer. The small, dark berries that follow are the part used in herbal medicine. They are harvested when ripe and dried.

The name comes from old stories about monks chewing the berries to dampen desire, and that is where monk's pepper comes from. The agnus castus part is usually traced to Greek and Latin words for chaste. I regard the monastic story as folklore and not as evidence of anything.

A buyer's note worth reading. Check that the label names the fruit and gives the Latin name Vitex agnus-castus. Most of the clinical research used a standardised dry extract of the berries at a defined daily amount, and the amount printed on a bottle of a different preparation does not translate directly. A product that gives no extract strength or ratio makes it hard to compare with anything in the research.

The active compounds

The berries contain iridoid glycosides (including agnuside and aucubin), flavonoids such as casticin, diterpenes and a small amount of essential oil.

The main proposed mechanism: dopamine and prolactin. In laboratory studies, compounds in the berries bind to dopamine receptors, and this is the usual explanation offered for why chaste tree is associated with lower prolactin. Prolactin is a pituitary hormone, and its relationship with the menstrual cycle is part of why chaste tree is traditionally used for cycle-related symptoms. This is a proposed mechanism. How fully it explains what happens in people is still debated.

How it is traditionally used

The EU herbal committee (HMPC) adopted a monograph on agnus castus fruit in 2018. It recognises two levels of evidence. Its well-established use is for the relief of symptoms before a period (premenstrual syndrome), with a daily dose of 20 mg of dry extract. It also lists a traditional use for the same purpose.

The monograph states that chaste tree is not for anyone under 18, and that it is not recommended in pregnancy or breastfeeding. It advises seeing a doctor before use in a number of situations, including oestrogen-sensitive cancers, pituitary disorders and the use of dopamine agonists or antagonists, oestrogens or anti-oestrogens. I would check the full document for the duration advice.

Western herbal practice has used chaste tree for cycle-related symptoms for a long time, and it is a typical choice for premenstrual breast tenderness, mood changes and irregular cycles. In Hormone Harmony it sits alongside Ashwagandha, Shatavari and Tulsi.

What the research shows

Here is how the evidence reads.

Good evidence: premenstrual symptoms. A randomised, double-blind, placebo-controlled trial published in the BMJ (Schellenberg, 2001) recruited 170 women with premenstrual syndrome. They took 20 mg of a standardised extract (Ze 440) daily for three menstrual cycles. More women in the chaste tree group were responders than in the placebo group, 52% compared with 24%. Seven mild adverse events were reported. A single trial of this size is not the last word, and the EU monograph's recognition of a well-established use reflects the wider body of evidence behind it, which I have not reviewed in full here.

Traditional evidence: cycle-related symptoms and breast tenderness. These uses rest on a long record of practitioner use.

Other uses. Chaste tree has been used for other hormone-related concerns such as fertility and menopause. I have not reviewed the trials for those uses in enough detail for this guide, so I make no claims about them.

Safety evidence. The BMJ trial reported seven mild adverse events. The EU monograph lists mild effects such as stomach upset, headache, dizziness and menstrual changes, and allergic skin reactions have been reported.

Sarah's clinical perspective

I use chaste tree in Hormone Harmony as a tincture alongside Ashwagandha, Shatavari and Tulsi.

I am careful with anyone using hormonal contraception, HRT or fertility medication, because chaste tree has direct activity on the pituitary-ovarian axis. I also ask anyone with a hormone-sensitive condition to speak to their GP or practitioner first.

Practical guidance

Dose. The EU monograph gives a well-established dose of 20 mg of dry extract a day for adults. A tincture has no equivalent trial-tested dose, so that figure cannot be converted into drops of a liquid. It is the amount in the monograph, and it is not a dosing instruction for any particular product.

Format. Most research used a standardised dry extract. A tincture is a traditional alternative.

Time to effect. Herbalists generally allow a few menstrual cycles to judge a response, which fits the three-cycle length of the main trial. Expecting a change within days is unrealistic.

Timing. The trial used a single daily dose. I know of no firm evidence that the time of day matters.

What it does not replace. Chaste tree does not replace medical assessment of heavy, painful or irregular periods, or a cycle that changes suddenly. A missed period when you might be pregnant needs a test, and chaste tree should be stopped in that case.

For how to take the EarthWise tonic specifically, the dose and full safety information are on the product page.

Common questions

Does chaste tree work like the contraceptive pill? No. It has no contraceptive action, and it should not be used with hormonal contraception without practitioner guidance.
Can chaste tree help with fertility? I have not reviewed the evidence for fertility in enough detail to say. If you are trying to conceive, speak to your GP or a practitioner first, because the EU monograph does not recommend chaste tree in pregnancy.
Is it suitable for menopause? The monograph's use is for premenstrual symptoms. I have not reviewed the evidence for menopause in enough detail to say.
How long should I take it? The main trial ran for three cycles. Beyond that I would review with a practitioner.
Are chaste tree, chasteberry and Vitex the same thing? Yes. They are common names for Vitex agnus-castus, and the berries are the part used.
Can men take chaste tree? The monograph's use is for premenstrual symptoms in women. I have not reviewed the evidence for men, and Hormone Harmony is formulated with women's health in mind.
Are there side effects? The reported ones are mostly mild, such as stomach upset, headache, dizziness or skin reactions, and menstrual changes.

Where chaste tree appears in the EarthWise range

Chaste tree is one of the four herbs in Hormone Harmony, Sarah's formula for hormonal support, where it sits with Ashwagandha, Shatavari and Tulsi.

If you are not sure which formula fits, the EarthWise health quiz is the best place to start. Full safety information is on each product page.

When to seek professional support

Chaste tree has real hormonal activity. Check with a practitioner first in these situations:

Hormonal contraception, HRT or fertility medication. The EarthWise guidance asks for practitioner advice before combining them with Hormone Harmony.
Oestrogen-sensitive conditions, such as certain breast, uterine or ovarian conditions. The EU monograph advises seeing a doctor first.
Pituitary disorders, or medicines that act on dopamine. The monograph advises seeing a doctor first.
Pregnancy and breastfeeding. Not recommended.
Thyroid conditions requiring medication. This applies to Ashwagandha in Hormone Harmony.
Under 18. The monograph does not recommend use in children and adolescents.
Heavy, painful or irregular periods, or a sudden change in your cycle. These need proper assessment by a GP.

Sarah Burt is a registered naturopath, medical herbalist and iridologist with 25+ years of clinical experience. All EarthWise tonics are formulated by Sarah based on her clinical protocols.

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This article is for informational purposes only and is not intended to diagnose, treat or cure any health condition. Always consult a qualified health practitioner before making changes to your health regimen.