Chasteberry is an herbal supplement that is used to support mood balance and hormone health in female and male horses.
The Chastetree berry (Vitex agnus-castus) plant is a shrub that grows in the Mediterranean and parts of Asia. The fruits and leaves contain active ingredients that influence hormonal balance in horses.
This herb is purported to support hypothalamic and pituitary function in horses. Anecdotally, chasteberry is said to help make moody mares easier to handle and may have a calming effect on aggressive stallions or geldings.
Chasteberry is not recommended for pregnant and lactating mares or growing horses because of potential effects on the reproductive system which have not been evaluated in these animals. [2]
Mad Barn’s Chasteberry Powder is made of pure dried chastetree berry fruit without any additional ingredients. It should be fed at a rate of 5-20 grams per day, increasing the serving size slowly to limit avoidance.
Why Use Chasteberry in Horses?
Chasteberry is primarily used in horses to enhance mood and improve behaviour, by regulating some hormone levels.
In traditional medicine, Chasteberry extract (Vitex) was originally thought to promote chastity, hence its name. The dried fruit was used by monks to decrease sexual desire. You might also find it labelled under the name Monk’s pepper.
Today, it is commonly used to treat premenstrual syndrome (PMS) and menopause in women. It has been shown to lower prolactin levels which helps alleviate symptoms of reproductive cycling in women. [1]
Though the effects of this herb have not been well-researched in horses, it is growing in popularity due to a strong body of anecdotal evidence from veterinarians and horse owners who have seen positive transformations in their equine companions.
Chasteberry can support optimal levels of several reproductive hormones: luteinizing hormone (LH), follicle-stimulating hormone (FSH), estrogen and progesterone. Therefore, chasteberry might help moody mares with behaviour issues that are related to being in season.
Chasteberry can alleviate some manifestations of Cushing’s Disease (PPID) but does not control hormonal output from the tumor. [17] There is also some evidence that it may interfere with the actions of