Vitex Isn’t a Cure-All. Read What Science Says it’s Actually Good For.
Vitex has been used for more than 2,500 years to treat a variety of gynecologic conditions, and it remains popular today as an herbal remedy for a wide variety of menstrual issues. In medieval Europe, it was popular among celibate clergymen for its purported ability to reduce libido [1.Czygan FC, Mayer JG. Vitex agnus-castus L, der oder das Keuschlamm. Ein kulturhistorischer essay. http://www.klostermedizin.de/html/moenchspfeffer.html.]. In recent decades, it has been used widely in Europe as a treatment for PMS [2.Blumenthal M. German Federal Institute for Drugs and Medical Devices. Commission E. Herbal Medicine: expanded Commission E monographs. 1st ed. Newton, Mass.: Integrative Medicine Communications, 2000.], cyclical breast pain, irregular cycles, and infertility. It is widely prescribed by gynecologists in Germany [3.Schilcher H. Phytotherapy and classical medicine. Journal of Herbs, Spices, and Medicinal Plants. 1994;2:71–80.].
But what is the evidence for Vitex’s efficacy, and what conditions is it best for? This post provides an overview of the studies that have been done on Vitex for treating various menstrual ailments.
What is Vitex?
Also referred to as Chasteberry, monk’s pepper, or Agnus Castus, Vitex is the fruit of the chaste tree. It is native to western Asia and southwestern Europe, and is now common in the southeastern US.
How does Vitex work?
The mechanism of Vitex’s action is only partially understood. It seems to have an indirect effect on several different hormones, especially prolactin and progesterone. There are several different theories about how it works:
- Binding dopamine receptors, which works to reduce secretion of prolactin by the pituitary gland, in turn inhibiting estrogen and progesterone[4.https://www.ncbi.nlm.nih.gov/pubmed/12809367].
- Binding opioid receptors, which decreases the secretion of gonadotropin-releasing hormone [5.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2993511/].
- Vitex contains many estrogen-like compounds that have an impact on the menstrual cycle [6.https://www.ncbi.nlm.nih.gov/pubmed/18415863].
Depending on the dose, Vitex may have very different effects. Low doses of Vitex have resulted in decreased estrogen levels and increased progesterone and prolactin levels—possibly caused by an inhibition of the release of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) [7.Mills S, Bone K. Principles and practice of phytotherapy: modern herbal medicine. Edinburgh: Churchill Livingstone, 2000.].
In some studies involving higher doses of Vitex, FSH and LH levels did not change[8.Mills S, Bone K. Principles and practice of phytotherapy: modern herbal medicine. Edinburgh: Churchill Livingstone, 2000.], while prolactin levels decreased.
This is a condition where elevated levels of prolactin suppress estrogen and progesterone, as when a woman is nursing. Aside from breastfeeding, hyperprolactinemia can also occur when someone has a benign pituitary tumor (called a microadenoma). The drug Bromocriptine is sometimes prescribed in these cases, but vitex seems to work just as well[9.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4528347/].
Yes: PMS and Breast Pain
In clinical trials for the treatment of PMS, Vitex reduced self-assessed symptoms including breast pain, bloating, constipation, and irritability[10.Blumenthal M. German Federal Institute for Drugs and Medical Devices. Commission E. The complete German Commission E monographs: therapeutic guide to herbal medicines. Austin, Tex.: American Botanical Council, 1998.].
In one recent, high-quality, prospective double blind randomized clinical trial, 170 women with a diagnosis of PMS received Vitex extract or a placebo for three menstrual cycles. More than half of the women taking Vitex experienced a 50 percent or greater reduction in symptoms[11.Schellenberg R. Treatment for the premenstrual syndrome with agnus castus fruit extract: prospective, randomised, placebo controlled study. BMJ. 2001;322:134–7.]
Another placebo-controlled, double blind trial of 104 women taking Vitex for at least three cycles showed that women in the treatment group had improvement of cyclical breast pain[12.Wuttke W, Splitt G, Gorkow C, et al. Treatment of cyclical mastalgia: results of a randomised, placebo-controlled, double-blind study. Geburtshilfe Frauenheilkd. 1997;57:569–74.].
Maybe: Irregular Cycles
There are not enough high-quality studies to show that Vitex can help improve menstrual cycle regularity. The studies that do exist are small, with modest findings.
Results of a small study involving 96 women with a variety of fertility disorders (38 women had secondary amenorrhea, 31 had luteal phase defect, and 27 had unexplained infertility) showed that patients receiving Vitex conceived more often than patients taking a placebo. Hormone levels between the treatment group and the placebo group did not differ, but in women with amenorrhea and luteal phase defect, pregnancy occurred in the treatment group twice as often as in the placebo group.
However, the total number of patients who became pregnant was small (15 women), the treatment was only administered for three months, and the product used in the study (Mastodynon, not available in the US) is an herbal blend that contains five additional ingredients besides Vitex[13.25. Gerhard I, Patek A, Monga B, Blank A, Gorkow C. Mastodynon (R) bei weiblicher Sterilitat. Forsch Komplementarmed. 1998;5:272–8.].
Maybe: Luteal Phase Defect
In a small study involving 52 patients with luteal phase defects, women in the treatment group were found to have improved luteal phase progesterone synthesis and higher levels of luteal phase estradiol. This study supports the use of Vitex for luteal phase defects, but the actual effect on fertility was not reported[14. Milewicz A, Gejdel E, Sworen H, Sienkiewicz K, Jedrzejak J, Teucher T, et al. Vitex agnus castus extract in the treatment of luteal phase defects due to latent hyperprolactinemia. Results of a randomized placebo-controlled double-blind study. Arzneimittelforschung. 1993;43:752–6.].
A recent double-blind placebo-controlled study of 30 women showed higher levels of mid-luteal phase progesterone levels and an increased number of pregnancies in the 15 women who took a Vitex-containing supplement for five months[15.Westphal LM, Polan ML, Trant AS, Mooney SB. A nutritional supplement for improving fertility in women: a pilot study. J Reprod Med. 2004;49:289–93.].
No: Hypothalamic Amenorrhea
There is no evidence that Vitex can restore cycles when someone has missing periods due to hypothalamic amenorrhea. Some people suggest taking Vitex to help increase progesterone levels, but in a normal cycle progesterone is only elevated after ovulation. Consistently higher baseline levels of progesterone would not be helpful, and according to some studies in primates, may even prevent ovulation.
Read more detailed information about why Vitex is not advised for hypothalamic amenorrhea.