Agnus castus – also known as chasteberry – is a traditional herbal medicine derived from the fruit of a Mediterranean shrub Vitex agnus-castus. The berries were traditionally used by monks to reduce sex drive and help them to remain celibate, hence its name, but higher therapeutic doses appear to have the opposite effect.
Health benefits of Agnus castus
Agnus castus contains a number of substances that interact with dopamine receptors in the brain. These receptors are involved in motivation, pleasure, memory, learning, understanding and mood.
In low doses, Agnus castus increases the secretion of prolactin hormone from the pituitary gland, which accounts for its traditional use as a celibacy aid. In higher doses, however, agnus castus blocks the receptors to suppress prolactin hormone secretion and has the opposite effect. In a group of 20 health males, for example, a dose of 120mg Agnus castus increased prolactin levels by 16%, but at a dose of 480mg, prolactin levels fell by around 10%.
Other substances present within Agnus castus, such as apigenin, have been shown to stimulate oestrogen receptors.
Agnus castus for women
Among women, Agnus castus is a traditional herbal medicine used to treat gynaecological problems such as a lack of periods, painful periods, premenstrual syndrome, infertility and menopausal symptoms.
Agnus castus and PMS
Agnus castus fruit extracts are a traditional herbal medicine used to improve the symptoms of premenstrual syndrome such as menstrual cramps, bloating, mood swings, irritability and cyclical breast pain.
A study involving 170 women with PMS, showed that Agnus castus fruit extracts improved symptoms by 52 per cent, compared with the same improvement in just 24 per cent of those taking a placebo. The greatest improvement was seen in the reduction of irritability, mood alteration, anger, headache and breast fullness. Other studies have found Agnus castus to be effective in relieving physical symptoms such as headaches, sore breasts, bloating and fatigue as well as increased appetite, sweet cravings, nervousness/ restlessness, anxiety, depression, mood swings and lack of concentration.
Agnus castus and infertility
Agnus castus may improve fertility where difficulty in conceiving is linked with low progesterone levels during the second (luteal) phase of the menstrual cycle (from ovulation to the onset of menstruation). In a study involving 67 women with infertility linked with infrequent or absent periods, some took Agnus castus for 3 months, and some took inactive placebo. Spontaneous menstruation, improved progesterone levels in the luteal phase, ovulation and pregnancy were achieved more often in women taking Agnus castus (85%) than on placebo (45%). It should only be used to treat infertility under medical supervision, however, and stopped as soon as pregnancy is suspected. The safety of Agnus castus during pregnancy has not been confirmed.
Agnus castus and PCOS
Agnus castus berries are used to improve symptoms of PCOS (polycystic ovary syndrome) but so far there has been little research into its effectiveness, and its use is based on anecdotal and traditional evidence.
Agnus castus for men
As Agnus castus is thought to have an anti-androgen effect in men, it is not generally recommended for use in males. Traditionally it has been given to treat male impotence, premature ejaculation, prostatitis and lack of sexual sensations but is best used under the supervision of a medical herbalist.
Agnus castus dose
A typical dose is 4mg Agnus castus fruit extracts, equivalent to 28mg to 52 mg of fresh Agnus castus berries. Select products standardized for their agnuside or casticin content.
Agnus castus is slow acting. It takes an average of 25 days for symptoms to start improving and up to six months to achieve its full effects.
Reported side effects are mild, the most common including nausea, headache, gastrointestinal disturbances, menstrual disorders, acne, itching and skin rash. Excess Agnus castus may cause a crawling sensation on the skin.
Agnus castus safety
Agnus castus is not recommended during pregnancy or breastfeeding, except under medical supervision. It should not be taken at the same time as other hormone treatments, such as HRT and hormonal methods of contraception.
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