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The results of a randomized, double-blind, placebo-controlled crossover trial using St. John’s Wort for PMS sufferers were recently published. 36 women with regular menstrual cycles who were diagnosed with mild PMS were randomly assigned to receive St. John’s Wort tablets (900 mg/day and standardized to 0.18% hypericin and 3.38% hyperforin) or placebo for two menstrual cycles. After a one month no treatment cycle, women were crossed over to the opposite group, for two additional cycles.

Symptoms were rated using the Daily Symptom Report, The State Anxiety Inventory, the Beck Depression Inventory and the Aggression Questionnaire and Barratt Impulsiveness Scale. Numerous hormones and physiological markers were also measured in the follicular and luteal phases: follicle-stimulating hormone (FSH), luteinizing hormone (LH), estradiol, progesterone, prolactin, testosterone, cytokine interleukins= IL-1B, IL-6, IL-8, interferon and tumor necrosis factor alpha.

clip_image002St. John’s wort was statistically more beneficial than placebo in food cravings, swelling, poor coordination, insomnia, confusion, headaches, crying and fatigue. There were no significant effects of St. John’s wort compared with placebo in any of the biochemical blood measurements. St. John’s wort was not statistically more beneficial in anxiety, irritability, depression, nervous tension, mood swings, feeling out of control and pain-related symptoms during two cycles of treatment. However, these pain-related symptoms appeared to improve more than placebo towards the end of each treatment period

Commentary: The results of this PMS study demonstrate once again, the benefit of St. John’s Wort for the treatment of PMS. In this study, it was determined their PMS was mild. The benefit received by women taking St. John’s Wort was achieved during the first menstrual cycle in which it was taken. While St. John’s Wort did not prove to be statistically better than placebo for mood and pain-related PMS symptoms, the pain symptoms did appear to improve more than placebo towards the end of each treatment period, implying that there may be more pain benefits with St. John’s wort after a longer duration of treatment. Several other studies have shown benefit with St. John’s wort.

Reference: Canning S, Waterman M, Orsi N, et al. The efficacy of Hypericum perforatum (ST John’s Wort) for the treatment of premenstrual syndrome. CNS Drugs 2010; 24(3):207-225.