Agnus castus (Vitex agnus castus)
A large shrub native to southern Europe, Agnus castus produces small fragrant lilac or white flowers, followed by red berries that are dried for medicinal use.
It was mentioned in Homer’s Iliad in the 6th century BC as a symbol of chastity (‘castus’ is Latin for chastity), hence it’s common name ‘Chaste berry’. Although best known as a female herb, it was also used as a condiment in monasteries to curb male libidos, hence an old name ‘Monk’s pepper’. In fact, it does taste good, with an aromatic black pepper-like flavour.
Medicinal Use
Agnus castus balances female hormone production in conditions including absent or irregular periods, period pain, PMS, short and long cycles, as well as menopausal symptoms and infertility. It effects reproductive hormones indirectly via the anterior pituitary - the master gland of the endocrine system that controls release of most hormones, hence its complex effects, for instance increasing the ratio of progesterone to oestrogen and decreasing prolactin levels.
Agnus castus is well supported by research: a 1994 study reported that 70% - 80% of women with menstrual irregularities experienced improvements after several months; a 2001 study on PMS found that taken for 3 cycles it improved symptoms of anger, depression, headaches, breast tenderness, bloating and fluid retention; and in a 2000 study, 93% of patients with ‘type C’ PMS reported improvements in headaches, sweet cravings, palpitations and dizziness.
Agnus castus promotes fertility by helping establish healthy ovulation cycles and improve relative deficiencies of progesterone - one cause of infertility, with a 1980s study of 45 infertile women with low progesterone reporting that after 3 months on Vitex, 25 had normal progesterone levels, 7 had improved levels and 7 were pregnant!
Hormone modulating effects makes Agnus castus relevant for menopausal symptoms, fibroids, endometriosis, and ovarian cysts. It is also an acne herb, with a trial on males and females reporting improvement in 70% of subjects after 3 months, likely due to reductions in testosterone.
Although Agnus castus should not be taken at the same time as hormone treatments such as the contraceptive pill, herbalists recommended taking it for a few months after stopping the pill to help kick-start the hormones and re-establish a natural cycle.
Dosage
Herbalists normally prescribe a liquid extract (tincture) at a dose of 15 – 20 drops in water first thing in the morning for hormonal imbalance. At a higher dose it has more of a suppressing effect in conditions such as menopause, acne, and fibroids. Agnus castus is safe to take long term but hormonal rebalancing can often be achieved in 3 – 4 months.
Safety
Avoid if taking the contraceptive pill, HRT, conventional fertility treatments, and when pregnant or breast feeding. Cease use if a previously regular cycle becomes irregular or if mid cycle spotting occurs.