The Science - Vitex Relationship

For the last 50 years, vitex has been used to treat problems of the female reproductive system including premenstrual syndrome (PMS), menstrual cycle irregularities, dysfunctional uterine bleeding, infertility, mastalgia, decreased lactation and acne (Rotblatt & Ziment, 2002). Although around 30 clinical trials in Europe have been conducted to study its effects, most of these studies were involved in post-market surveillance and were poorly designed (Rotblatt & Ziment, 2002). In addition, there are very few recent clinical trials done to further investigate its uses and efficacy.

The study by He et al. is one of the most current studies that examined the efficacy of vitex in relieving mild to severe symptoms of PMS (He et al., 2009). With 202 Chinese women, they were able to show that compared to placebo, vitex caused a significant improvement in the symptoms of PMS from baseline to the last month of treatment (termination). These scores were recorded using the self-assessment tools PMS diary (PMSD) and Premenstrual tension syndrome self-rating scale (PTSD). 

Although termination PMSD scores from both the placebo and the treatment groups significantly decreased from baseline (both p<0.0001), the reduction in the treatment group (22.71 ± 10.33) was significantly greater than the reduction in the placebo (15.50 ± 10.94) (p<0.0001). Termination PTSD scores were also significantly lower from baseline between and within groups (both p<0.01). Scores of the placebo group decreased by 12.44 ± 10.43 while those in the treatment group decreased by 16.63 ± 10.07. This study presented a 60% improvement in symptom scores and was considered clinically significant.

The study was described as prospective, randomized, controlled and double-blind, a type of study that provides the highest quality of evidence. Although it did not elaborate on the randomization and blinding method, this study is still commendable for including power calculations, for considering confounding factors, for using two assessment tools to measure the outcome and for reporting attrition and adverse events. The protocol was sound, detailed and properly executed, rendering the results of this study valid.  

The study by Kilicdag et al. on the other hand, is not as well designed. They studied the efficacy of vitex as a treatment for mild hyperprolactinemia and mastalgia compared to the drug bromocriptine (Kilicdag et al., 2004). The results show that there was a significant decrease in prolactin levels in both the vitex group (416.47 ± 248.93 mIU/l) and the drug group (412.36 ± 322.78 mIU/l ) (both p<0.0001) and a significant reduction in pain scores associated with mastalgia in both the vitex group (4.90 ± 2.10) and the drug group (5.32 ± 2.24) (both p<0.0001), both from baseline. There were no differences in efficacy between vitex and bromocriptine in treating hyperprolactinemia (p = 0.96) nor mastalgia (p = 0.55). 

This study was full of design flaws. The sample size was extremely small (n=20 per group per disorder), they were not randomized nor blinded, the methods used to report the outcomes, attrition rates and baseline characteristics were not reported and most importantly, there were no controls used. These serious flaws question the validity of the results, thus this study does not provide evidence of the therapeutic effects of vitex on hyperprolactinemia nor mastalgia.