Vitex Agnus-Castus (Chasteberry): Benefits, Side Effects, and Myths

1. Alleviates breast pain

Chasteberry has been used in traditional medicine to relieve breast pain associated with the menstrual cycle. 

According to one study, chasteberry may reduce elevated prolactin levels, which helps balance other hormones in the body and can relieve breast pain.

2. Relieves PMS symptoms

Chasteberry may help ease PMS symptoms such as:

• Constipation
• Irritability
• Depressed mood
• Migraines

However, since many of the studies regarding the use of chasteberry in easing PMS symptoms are relatively small, additional research is needed before a strong conclusion can be made.

3. May enhance fertility

Because Vitex agnus-castus can help regulate prolactin levels, it may have a positive effect on fertility, especially in women who have a luteal phase defect.

Luteal phase defect refers to a shortened second half of the menstrual cycle, which is often linked to high levels of prolactin and can make it difficult to achieve pregnancy. Other causative factors of infertility are amenorrhea and other menstrual disorders.

Small studies have reported that women with amenorrhea and other menstrual disorders were able to conceive after taking chasteberry. However, more studies are needed to reach a strong conclusion.

4. Helps prevent insect bites

Vitex agnus-castus may help with insect bites. 

According to one study, chasteberry sprays may be effective in repelling mosquitoes, flies, ticks, lice, and fleas for about 6-7 hours. 

Other potential benefits associated with chasteberry include:

• Treatment of fibroid cysts
• Reduced symptoms of menopause
• Epilepsy prevention
• Reduced headaches

However, many of these purported benefits lack sufficient scientific evidence.

Chasteberry is generally safe when taken in about 3.2-40 mg doses by mouth daily for up to 6 months. Some may experience minor side effects with chasteberry, which include:

• Nausea
• Upset stomach
• Mild skin rash
• Increased acne
• Headache
• Heavy menstrual flow

Chasteberry has been used in traditional medicine for various purposes, but many uses are not supported by substantial scientific evidence:

• Boosting milk production: In the past, chasteberry was indicated for boosting milk supply in breastfeeding mothers. Evidence supporting this claim, however, is weak.
• Treating endometriosis: Theoretically, because chasteberry regulates hormonal imbalances, it should be effective in treating endometriosis. However, there are no studies to confirm this health benefit.
• Preventing baldness: The hormone-balancing ability of chasteberry is believed to enhance hair growth in men. However, no research supports this claim.
• Treating acne: There are no current studies that prove the effectiveness of chasteberry in treating acne. 
• Boosting libido: Chasteberry was used in the past to regulate libido. However, there is no clinical data to support this claim.

Chasteberry should be avoided in certain conditions:

• Pregnancy
• Breastfeeding
• Endometriosis
• Uterine fibroids
• Breast, uterine, or ovarian cancer
• Parkinson’s disease
• Schizophrenia and other psychotic disorders

People taking the following drugs should avoid taking chasteberry because it can lead to adverse interactions:

• Birth control pills
• Estrogen pills
• Antipsychotic drugs
• Metoclopramide
• Dopamine agonists (medications for Parkinson’s disease)