--- title: Does St. John's wort help with premenstrual symptoms? | Niyora description: There was a slight trend suggesting it might help, but the result was not statistically significant, so we cannot be sure it works. url: https://niyora.com/research/papers/the-significance-of-nonsignificance-in-randomized-controlled-studies-a-2004/ --- - [Niyora](https://niyora.com/) - [Research](https://niyora.com/research/) - [Library](https://niyora.com/research/library/) - Does St. John's wort help with premenstrual symptoms? Randomised trial, 2004 # Does St. John's wort help with premenstrual symptoms? There was a slight trend suggesting it might help, but the result was not statistically significant, so we cannot be sure it works. Moderate study design 169 women (125 completed) with recurrent premenstrual symptoms in England ## What they did 169 women with recurrent premenstrual symptoms were recruited. After a baseline cycle, 125 women completed 2 treatment cycles with either 600 mg of St. John's wort or placebo. Symptoms were tracked daily in a menstrual diary, with anxiety-related symptoms as the primary measure. ## What they found St. John's wort showed a trend toward being better than placebo for anxiety-related symptoms, but this difference was not statistically significant. The authors noted this might be due to insufficient study size rather than the herb not working. ## What it means for you This study could not prove St. John's wort works, though a larger study might find an effect. The main limitation is that only 125 women completed the study, which may not be enough to detect a real benefit if one exists. 169 women recruited 125 women completed 600 mg dose per day ## About the study Original title The significance of "nonsignificance" in randomized controlled studies: a discussion inspired by a double-blinded study on St. John's wort (Hypericum perforatum L.) for premenstrual symptoms Authors Hicks SM, Walker AF, Gallagher J et al. Journal Journal of alternative and complementary medicine (New York, N.Y.) Year 2004 Study design Randomised trial What was tested 600 mg St. John's wort standardized to 1800 micrograms hypericin versus placebo for 2 menstrual cycles Read the paper [doi.org/10.1089/acm.2004.10.925](https://doi.org/10.1089/acm.2004.10.925) ## Topics [Premenstrual syndrome (PMS)](https://niyora.com/research/topics/condition-pms/)[Anxiety and tension](https://niyora.com/research/topics/symptom-anxiety/)[Other herbal medicine](https://niyora.com/research/topics/treatment-herbal-other/) Research tells you what helps on average. Niyora helps on the day it hits. Calm down, see it another way, and decide what to say, with a PMS and PMDD app built by a doctor. ## Related studies Guideline, 2024 How should Xiangshao Granules be prescribed for premenstrual tension syndrome? Systematic review, 2021 Does damask rose help reduce menstrual pain, headache, fatigue, anxiety, and bloating? Systematic review, 2008 What treatments work best for PMS and PMDD? Randomised trial, 2025 Does Nigella sativa reduce PMS symptoms in women? Review, 2023 Can herbs and supplements help with PMS symptoms? Non-randomised trial, 2019 Does exercising before your period help with pain and anxiety? Ask AI about this page Copy prompt ChatGPT ↗ Claude ↗ Perplexity ↗ Google AI Mode ↗ Grok ↗