Agnus Castus: Herbal support to help balance female hormones the natural way

Agnus Castus is an aromatic shrub of the Verbenaceae family, which is notable for spikes or clusters of flowers that have an aromatic scent. The plant can grow up to 9 metres tall and is native to Europe and Central Asia. It has violet or rose-coloured flowers and small dark brown to black hard fruits the size of peppercorns. In herbal medicine, it is the fruits that have traditionally been used for a wide range of problems (mainly those associated with female hormonal imbalance), and its use can be dated back to the days of Hippocrates 2,500 years ago.

The botanical name of the plant is Vitex agnus-castus and it is also known as chaste tree, chasteberry and monk’s pepper tree. Historically, some of the names it is referred to come from the belief that it was an anaphrodisiac, as it was thought to reduce the libido in the Middle Ages. There is, however, no clinical data to support this.


The berries of the plant are dried and made into either a powder or tincture. It is available as a capsule, liquid extract, tablet, and essential oil.

Active constituents

The biological activity of Agnus Castus is likely attributed to many chemical components, including flavonoids such as casticin, kaempferol, apigenin, orientin and isovitexin, and iridoid compounds including aucubin and agnuside. It also contains diterpene alkaloids such as vitexlactams A, B, and C and clerodadienol.

Mechanisms of Action

The mechanisms of action of Agnus Castus are not fully understood but its principal    pharmacological effect on the body is the inhibition of prolactin secretion. Various studies have indicated that the seeds produce a modulating effect on the hypothalamus-pituitary system, and hence promote hormonal balance and a regular menstrual cycle. Therapeutic properties are credited to its indirect actions on prolactin and progesterone, in particular.

Agnus Castus increases progesterone by increasing luteinizing hormone (LH) and inhibiting follicle-stimulating hormone (FSH) and prolactin levels. 1,2 It can also increase dopamine activity in the brain, which also results in a reduction of prolactin release. Studies have shown central dopaminergic activity in vitro and in vivo.3-5

Prolactin and Dopamine

Prolactin is a hormone made by the pituitary gland and causes the breasts to grow and produce milk during pregnancy and after childbirth. Levels are, hence, normally elevated in pregnant and breastfeeding women. Higher than normal levels of prolactin in women who are neither pregnant or lactating are associated with infertility, irregular menstruation, loss of libido and other menstrual disorders.

One of the key regulators of the production of prolactin is the hormone dopamine, which is produced by the hypothalamus. Dopamine suppresses the pituitary secretion of prolactin via the dopamine receptor 2. Hence, more dopamine means less prolactin.

Agnus Castus has been shown to influence dopaminergic activity and subsequently has prolactin-lowering effects.1-3 It has also been shown to bind opiate receptors, which in turn promotes dopamine activity.1,4,5 The chemical components of Agnus Castus, casticin and the diterpenes, in particular, are believed to reduce elevated prolactin levels.6,7

One study showed that the diterpene clerodadienol binds dopamine receptors and suppresses prolactin release as effectively as dopamine.6 Furthermore, animal studies suggest that casticin inhibits estradiol stimulation of prolactin secretion via suppression of pituitary α-estrogen receptor mRNA expression.8

Oestrogen and Progesterone

High levels of oestrogen and/or low levels of progesterone are believed to play a crucial part in many disorders associated with hormone imbalance.

Oestrogen dominance is a term that refers to having an excess of oestrogen in the body in relation to progesterone.  Many women are in a state of oestrogen dominance and can hence suffer with the symptoms associated with it such as PMS (discussed further below), irregular menstruation, heavy bleeding, fibroids, endometriosis, depression, anxiety, irritability and so on.

What causes oestrogen dominance?

Medications such as hormonal contraceptives, obesity (fat cells produce extra oestrogen), gut dysbiosis, chronic stress, exposure to xenoestrogens (chemicals that mimic the behaviour of oestrogens), and HRT.  Poor excretion of oestrogen is also a common factor. Supporting the liver is important and can help it to safely detoxify and help clear oestrogen. A liver cleansing herb such as milk thistle can be beneficial and will help eliminate toxins and compounds that the body does not need.

The health and regularity of the bowel is also key. Supporting the gut and maintaining regular bowel movements also allows oestrogen to be excreted adequately.

Progesterone is responsible for maintaining pregnancy, monthly menstruation, and helps prepare the female body for conception. It has been described as ‘natures valium’ due to its relaxing effects. Low levels can be caused by many factors and can cause a number of menstrual disorders. Low progesterone can often be due to irregular ovulation.

Progesterone production can be supported and increased using herbal support.1 Agnus Castus stimulates the pituitary to produce LH which in turn signals the ovaries to produce more progesterone. It may therefore help to boost the production of progesterone naturally, improving the oestrogen to progesterone ratio, resulting in hormonal balance.



PMS is often a sign of hormone imbalance and oestrogen dominance. It refers to a variety of emotional, behavioural, and physical symptoms that occur up to two weeks before the onset of menses.1 It is characterised by physical symptoms such as menstrual cramps, headaches, skin problems and breast tenderness; and emotional symptoms including irritability, mood swings depression and anxiety. It is estimated that as many as 30% of women can experience moderate to severe PMS and between 3 and 8 % of women in the UK suffer from premenstrual dysphoric disorder (PMDD)2, a severe form of PMS, which can have a significant impact on life. PMS symptoms have been linked with a low level of progesterone.

A clinical survey published in 1992 evaluated the effect of an Agnus Castus preparation on 1,542 women diagnosed with PMS. Treatment of 40 drops daily lasted an average of 166 days. Both physicians and patient assessed efficacy, with 90 percent reporting relief of symptoms, after an average treatment duration of 25.3 days.3

In other clinical trials, Agnus Castus reduced many symptoms associated with PMS, especially breast pain, irritability, depression and low mood, irritability, and headache.4-7

Amenorrhea and Menstrual Disorders

A healthy menstrual cycle depends on the proper balancing of hormone levels. Agnus Castus has been shown to correct menstrual irregularities, including amenorrhea (the absence of menstruation), specifically when caused by latent hyperprolactinemia (a condition in which a person has higher-than-normal levels of the hormone prolactin in the blood) owing to its ability to inhibit prolactin secretion.1

Luteal phase disorder is primarily caused by progesterone deficiency in the first phase of the menstrual cycle. An RCT of women with luteal-phase defect menstrual cycle irregularities attributable to elevated prolactin found that 20 mg of Vitex lowered prolactin levels and normalized menstrual cycles after 3 months.2


The hormone-balancing effects of Agnus Castus may also help to alleviate the unpleasant symptoms of menopause. In one study, vitex oils were given to 23 women in menopause. Women reported improved menopause symptoms, including better mood and sleep.1


A regular menstrual cycle is important for conception, and menstrual cycle disorders can be one reason why some women have problems conceiving. This can be due to too much prolactin and too little progesterone. Agnus Castus has been shown to help regulate both.

An RCT compared the use of Agnus Castus and other supportive nutrients to placebo in 93 women with infertility. After 3 months, progesterone levels in women taking Agnus Castus had increased compared with those receiving placebo. Furthermore, 13 of the 53 women became pregnant compared with none in the placebo group.1,2

Polycystic Ovarian Syndrome (PCOS)

PCOS is a complex endocrine disorder and is said to affect around 6-8% of the female population in the reproductive age.1 It is caused by an imbalance of the female sex hormones and higher levels of hormones called androgens (e.g., testosterone and androstenedione). It is characterised by polycystic ovaries, lack or absence of ovulation and excessive presence of the male sex hormones. This can lead to irregular menstrual cycles, hirsutism (excessive hair growth), skin problems and infertility. In conditions like PCOS, Agnus Castus is helpful in restoring ovulation and regulating progesterone levels.

Agnus Castus helps to regulate prolactin, FSH, and LH, which may then regulate and balance testosterone levels, as well as levels of other reproductive hormones.2 This can be therapeutic in women with PCOS and elevated androgens.


Agnus Castus should not be used by anyone undergoing infertility treatment and is also not recommended by anyone on birth control. It should not be used by pregnant and breastfeeding women. There are no reported drug interactions but given its dopaminergic effects, the herb could potentially interfere with drugs that affect dopamine levels.

With a long traditional history of use, Agnus Castus can be a beneficial botanical alternative to address female hormonal imbalances and a range of symptoms associated with them.

If you have questions regarding the topics that have been raised, or any other health matters, please do contact me by phone or email at any time.
01684 310099

Amanda Williams and the Cytoplan Editorial Team


Mechanism of Action

      1. Brown D. (1994) Vitex agnus castus clinical monograph. Quarterly Review of Natural Medicine. 2:111–21.
      2. PG, M. et al. (1996) “The effects of a special Agnus castus extract (BP1095E1) on prolactin secretion in healthy male subjects,” Experimental and clinical endocrinology & diabetes : official journal, German Society of Endocrinology [and] German Diabetes Association, 104(6), pp. 447–453.
      3. et al. (2000) “Pharmacological activities of Vitex agnus-castus extracts in vitro,” Phytomedicine : international journal of phytotherapy and phytopharmacology, 7(5), pp. 373–381.
      4. Roemheld-Hamm, B. (2005) “Chasteberry,” American Family Physician, 72(5), pp. 821–824.
      5. Wuttke W. (1996). Dopaminergic action of extracts of Agnus Castus. Forschende Komplementarmedizen. 3:329–30.

Prolactin and Dopamine

      1. et al. (2000) “Pharmacological activities of Vitex agnus-castus extracts in vitro,” Phytomedicine : international journal of phytotherapy and phytopharmacology, 7(5), pp. 373–381.
      2. Roemheld-Hamm, B. (2005) “Chasteberry,” American Family Physician, 72(5), pp. 821–824.
      3. Wuttke W. (1996). Dopaminergic action of extracts of Agnus Castus. Forschende Komplementarmedizen. 3:329–30.
      4. DE, W. et al. (2011) “Opioidergic mechanisms underlying the actions of Vitex agnus-castus L,” Biochemical pharmacology, 81(1), pp. 170–177.
      5. DE, W. et al. (2006) “Activation of the mu-opiate receptor by Vitex agnus-castus methanol extracts: implication for its use in PMS,” Journal of ethnopharmacology, 106(2), pp. 216–221.
      6. W, W. et al. (2003) “Chaste tree (Vitex agnus-castus)–pharmacology and clinical indications,” Phytomedicine : international journal of phytotherapy and phytopharmacology, 10(4), pp. 348–357.
      7. G, S. et al. (1993) “Agnus castus extracts inhibit prolactin secretion of rat pituitary cells,” Hormone and metabolic research = Hormon- und Stoffwechselforschung = Hormones et metabolisme, 25(5), pp. 253–255.
      8. Q, Y. et al. (2010) “Casticin, a flavonoid isolated from Vitex rotundifolia, inhibits prolactin release in vivo and in vitro,” Acta pharmacologica Sinica, 31(12), pp. 1564–1568.

Oestrogen and Progesterone

      1. NA, I. et al. (2008) “Gynecological efficacy and chemical investigation of Vitex agnus-castus L. fruits growing in Egypt,” Natural product research, 22(6), pp. 537–546.


      1. A, R. (2003) “A review of treatment of premenstrual syndrome and premenstrual dysphoric disorder,” Psychoneuroendocrinology, 28 Suppl 3(SUPPL. 3), pp. 39–53.
      2. Yonkers, K. A., O’Brien, Prof. P. M. S. and Eriksson, Prof. E. (2008) “Premenstrual syndrome,” Lancet, 371(9619), p. 1200.
      3. Dittmar, F. W (1992) Premenstrual Syndrome (PMS): Treatment with a Phytopharmaceutical.  Gynäkol5(1):60-68.
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      5. C, L. et al. (1997) “Treatment of premenstrual tension syndrome with Vitex agnus castus controlled, double-blind study versus pyridoxine,” Phytomedicine : international journal of phytotherapy and phytopharmacology, 4(3), pp. 183–189.
      6. D, B. et al. (2000) “Efficacy of Vitex agnus castus L. extract Ze 440 in patients with pre-menstrual syndrome (PMS),” Archives of gynecology and obstetrics, 264(3), pp. 150–153.
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      1. Vitex Agnus-Castus – an overview | ScienceDirect Topics. Available at: (Accessed: July 22, 2021).
      2. [Vitex agnus castus extract in the treatment of luteal phase defects due to latent hyperprolactinemia. Results of a randomized placebo-controlled double-blind study] – PubMed (1993). Available at: (Accessed: July 22, 2021).


      1. L. (2003) “Vitex agnus castus essential oil and menopausal balance: a research update [Complementary Therapies in Nursing and Midwifery 8 (2003) 148-154],” Complementary therapies in nursing & midwifery, 9(3), pp. 157–160.


      1. Chaste Tree Berry (Vitex agnus castus 2) – Restorative Medicine. Available at: (Accessed: July 22, 2021).
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    1. Saul, S. (2017) “Effects of vitex agnes castus on hormonal imbalances in Polycystic Ovary Syndrome,” International Journal of Basic & Clinical Pharmacology, 6(8), pp. 2051–2055.
    2. S, N. et al. (2007) “The effects of Vitex agnus castus extract and its interaction with dopaminergic system on LH and testosterone in male mice,” Pakistan journal of biological sciences : PJBS, 10(14), pp. 2300–2307.

Last updated on 2nd February 2022 by cytoffice


10 thoughts on “Agnus Castus: Herbal support to help balance female hormones the natural way

  1. Can you please let me know why birth control may be a contraindication with this supplement. And which birth control in particular?

    1. Hi Michelle – Agnus Castus can increase progesterone so might be contraindicated with some birth control medications. It would be unwise to use this anyway if you are on any birth control medication.

      1. Hi Mary – Hi There – there is some evidence to suggest that the hormone-balancing effects of Agnus Castus may help with menopausal symptoms such as low mood and sleep disturbance, but there may also be other suitable products we could recommend if you would like to contact our Nutritional Therapy team at

  2. This article is factually misleading. PMS is not due to hormone imbalances nor oestrogen dominance. Women with PMS typically have normal hormone blood test results. The most likely theory currently is that their bodies ‘over-respond’ to normal fluctuations of hormones. Progesterone doesn’t ease PMS, or it would routinely be given by medical doctors as a treatment, and it isn’t. (And has been shown in several studies not to work.)
    The Yonkers research you cited very clearly makes all these points, and contradicts what is in this article. Other research shows that oestrogen patches (plus 12 days of progestogen per month) can ease PMS. (See Dr Nick Panay, chair of the National PMS association)
    Oestrogen dominance as a cause of PMS is very much an ‘alternative health’ theory. It’s fine if people believe it and if they find agnus castus works for them. (Agnus castus has indeed been shown in a couple of studies to help PMS for some women.) But please be careful portraying it as medical fact. I’d expect something more robust from Cytoplan.

    1. Hi Jane – Thank you for your comments, which I appreciate. PMS is a syndrome, therefore a collection of symptoms and hence can have multiple aetiologies. Oestrogen dominance (particularly imbalances of oestrogen detoxification pathways and excretion, which leads to hormonal fluctuations) can be one of these but appreciate this is not the full picture, which is why it is often difficult to ameliorate.
      As article states, Agnus Castus mechanisms of action include prolactin inhibition, indirect actions on progesterone, HPA axis normalisation and effects on dopamine all of which elicit effects on PMS and indirectly ameliorate hormonal fluctuations. Oestrogen is discussed as is also a factor to be considered, particularly pathways of detoxification and excretion, however this should be made clearer. Studies support and have shown improvements to PMS with the use of Agnus Castus, however, as with everything, this is not a one size fits all solution. Thanks, Amanda

  3. Am 70 years old. I have never had children though pregnant 3 times…
    termination age 17, miscarriage age 8, ectopic ag 30. I believe I became barren. Relatively no periods thereafter and little in the way of menopause.

    I was put onto Raloxofene, an oestrogenic for osteoporosis of the spine 15 years go then suddenly 2 months ago doctor took cancelled it. When I looked up oestrogenic dominance there are articles on its possible cause of uterine cancer amongst other things.

    Am wondering if Agnus Castus would be useful or should I stick to liver cleansing agents such as Mil Thistle.

    1. Hi Sally – I think it would be a great idea for our nutritional therapists to get a really thorough picture of your health profile so we can make some tailored recommendations. We would like to invite you to complete a health questionnaire online and the team will come back to your shortly.

  4. My daughter has been given Agnus castus combined with progesterone Utrogestan to take for her Polycystic Ovarian Syndrome and PMS. DO you think it is ok to use them both? Does this herbal work well together with Progesterone? She takes one every day the second for 10 days before her cicle.

    1. While not directly contraindicated, the suitability of taking the two products together would depend upon the individual. Presumably she has been recommended both products by a practitioner or medical professional who she has consulted with on a 1-1 basis – and if so, she should discuss any queries or concerns with the practitioner.

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