Chasteberry's therapeutic uses

• DEFINITION: Natural plant product used to treat specific health conditions.
• PRINCIPAL PROPOSED USES: Cyclic breast discomfort (often associated with premenstrual syndrome, or PMS), other PMS symptoms
• OTHER PROPOSED USES: Amenorrhea, female infertility, irregular menstruation, menopausal symptoms, acne, endometriosis, Polycystic Ovary Syndrome (PCOS)

Overview

Chasteberry is frequently called by its Latin name, vitex or, alternatively, agnus-castus. A shrub in the Verbena family, chasteberry is commonly found on riverbanks and nearby foothills in Central Asia and around the Mediterranean Sea. After its violet flowers bloom, a dark brown, peppercorn-size fruit with a pleasant odor reminiscent of peppermint develops. This fruit is used medicinally.

As the name implies, for centuries, chasteberry was thought to counter sexual desire. The Romans used a drink prepared from the plant’s seeds to diminish libido. In Ancient Greece, young women celebrating the festival of Demeter wore chasteberry blossoms to show that they were remaining chaste in honor of the goddess. Monks in the Middle Ages used the fruit for similar purposes, yielding the common name “monk’s pepper.”

Therapeutic Dosages

The typical dose of dry chasteberry extract is 20 milligrams, taken one to three times daily. Chasteberry is also sold as a liquid extract to be taken at a dosage of forty drops each morning. However, extracts that require lower or higher dosing are also available.

Therapeutic Uses

The modern use of chasteberry dates to the 1950s, when the German pharmaceutical firm Madaus first produced a standardized extract. This herb has become a standard European treatment for cyclic breast tenderness, a condition related to premenstrual syndrome (PMS) that is sometimes called cyclic mastitis, cyclic mastalgia, mastodynia, or fibrocystic breast disease. Chasteberry also appears to be useful for general PMS symptoms.

Chasteberry is believed to work by suppressing prolactin release from the pituitary gland. Prolactin is a hormone that naturally rises during pregnancy to stimulate milk production. Inappropriately increased prolactin production may be a factor in cyclic breast tenderness and other symptoms of PMS.

Elevated prolactin levels can also cause a woman’s period to become irregular and even stop. For this reason, chasteberry is sometimes tried when menstruation is irregular or stops altogether (amenorrhea). Persons should not attempt to self-treat significant menstrual irregularities without a full medical evaluation. Serious medical conditions could result.

High prolactin levels can also cause infertility in women. For this reason, chasteberry is sometimes tried as a fertility drug; however, double-blind studies performed to evaluate this possible use have failed to return statistically significant results. Chasteberry is sometimes used for menopausal symptoms, but there is as yet no evidence that it is effective, either alone or in combination with other herbs. Finally, although research is limited and not yet supported by meaningful scientific studies, chasteberry has also been recommended by some as an acne treatment and to reduce the symptoms of endometriosis and PCOS.

Scientific Evidence

There is a growing body of scientific research supporting the use of chasteberry.

Cyclic mastalgia. A double-blind, placebo-controlled trial of ninety-seven women with symptoms of cyclic mastalgia found that treatment with chasteberry extract significantly reduced pain intensity by the end of one menstrual cycle. The reduction continued to increase throughout the second menstrual cycle, and at the end of both the first and the second cycle, women in the treated group were doing better than those receiving a placebo.

However, in the third cycle, the benefits of chasteberry treatment reached a plateau, while the placebo group continued to improve. At the end of the third cycle, those receiving chasteberry were still doing better, but the difference was no longer statistically significant.

Another double-blind trial of 104 women compared a placebo against two forms of chasteberry (liquid and tablet) for at least three menstrual cycles. The results showed statistically significant and comparable improvements in the treated groups, compared with a placebo.

Benefits were also seen in a double-blind trial that enrolled 160 women with cyclic breast pain. The women were given either chasteberry, a drug related to progesterone, or a placebo and were followed for at least four menstrual cycles. Although there were many dropouts, the results again suggest that chasteberry is superior to a placebo.

Premenstrual syndrome (PMS). A double-blind, placebo-controlled study of 178 women found that treatment with chasteberry over three menstrual cycles significantly reduced general PMS symptoms. The dose used was one tablet three times daily of a dry chasteberry extract. Women in the treatment group experienced significant improvements in symptoms, including irritability, depression, headache, and breast tenderness. In a similar study, 217 women with moderate to severe PMS were randomized to receive chasteberry extract or placebo. After three menstrual cycles, the women in the treatment group reported fewer symptoms. A smaller trial involving sixty-seven women also reported on the effectiveness of chasteberry for PMS. Chasteberry, in combination with St. John’s wort, was also studied for PMS symptoms during late menopause with favorable results in at least one small trial.

Double-blind, placebo-controlled trials on chasteberry for the relief of PMS symptoms continued in the twenty-first century. A 2017 study published in the Journal of Alternative and Complementary Medicine found significant improvements in PMS symptoms when participants were given chasteberry over three menstrual cycles. A meta-analysis of double-blind, placebo-controlled trials of chasteberry for PMS symptoms, published in 2019 in BMC Complementary Medicine and Therapies, reported that women saw a 50 percent reduction in their PMS symptoms.

There is also some conflicting evidence, though. A double-blind trial compared chasteberry to vitamin B₆ (pyridoxine) instead of a placebo. The two treatments proved equally effective. However, because vitamin B₆ itself has not been shown effective for PMS, these results mean little.

Two other studies are often cited in support of chasteberry as a treatment for PMS. These were informal reports regarding about three thousand women with PMS who were given chasteberry by their physicians. The physicians rated chasteberry as effective about 90 percent of the time, but in the absence of a control group, these reports are not very meaningful.

Irregular menstruation. One double-blind trial followed fifty-two women with a form of irregular menstruation known as luteal phase defect. This condition is believed to be related to excessive prolactin release. After three months, the women who took chasteberry showed significant improvements.

Safety Issues

No detailed studies of the safety of chasteberry have been conducted. However, its widespread use in Germany has not led to any reports of significant adverse effects other than a single case of excessive ovarian stimulation possibly caused by chasteberry.

Because it lowers prolactin levels, chasteberry is not an appropriate treatment for pregnant or nursing women. Safety in young children or those with severe liver or kidney disease has not been established.

There are no known drug interactions associated with chasteberry. However, it is conceivable that the herb could interfere with hormones or medications that affect the pituitary gland. 

Bibliography

"Chasteberry: Usefulness and Safety." National Center for Complementary and Integrative Health, www.nccih.nih.gov/health/chasteberry. Accessed 7 Oct. 2024.

Csupor, Dezső, et al. "Vitex agnus-castus in Premenstrual Syndrome: A Meta-Analysis of Double-Blind Randomised Controlled Trials." Complementary Therapies in Medicine, vol. 47, 2019, p. 102190, doi.org/10.1016/j.ctim.2019.08.024. Accessed 7 Oct. 2024.

He, Z., et al. "Treatment for Premenstrual Syndrome with Vitex agnus castus: A Prospective, Randomized, Multi-center Placebo Controlled Study in China." Maturitas, vol. 63, no. 1, 2009, pp. 99-103.

Ma, L., et al. "Evaluating Therapeutic Effect in Symptoms of Moderate-to-Severe Premenstrual Syndrome with Vitex agnus castus (BNO 1095) in Chinese Women." Australian and New Zealand Journal of Obstetrics and Gynaecology, vol. 50, no. 2, 2010, pp. 189-193.

Van Die, M. D., et al. "Effects of a Combination of Hypericum perforatum and Vitex agnus-castus on PMS-like Symptoms in Late-Perimenopausal Women: Findings from a Subpopulation Analysis." Journal of Alternative and Complementary Medicine, vol. 15, no. 9, 2009, pp. 1045-1048.

"What Is Chasteberry, and What Can It Do?" Cleveland Health, 22 Nov. 2022, health.clevelandclinic.org/chasteberry-benefits-and-risks. Accessed 15 Aug. 2023.