Evening Primrose Oil for Menopause Hot Flashes: Systematic Review and Meta-Analysis

Hormone replacement therapy (HRT) used to treat hot flashes has side effects, such as an increased risk of coronary heart disease and breast cancer. There are ongoing controversies regarding the risk of ovarian cancer associated with HRT. HRT is best avoided in conditions such as liver or gallbladder disease and gastrointestinal disorders. Evening primrose oil (EPO) has been used as an alternative treatment for hot flashes. We conducted a systematic review of randomized controlled trials and controlled clinical trials, following the PRISMA guidelines, to compare EPO with placebo or other interventions in alleviating hot flashes in menopausal women. We analyzed the data using Review Manager version 5.3, in conjunction with the Cochrane Collaboration tool. The severity of hot flashes was lower when EPO was administered for less than 6 months compared to placebo. However, there was no significant difference in the frequency and duration of hot flashes between EPO and placebo. Participants who received EPO complained of mild nausea and headache. EPO did not show any significant difference in the severity of hot flashes compared to black cohosh at 4 weeks; but the hot flashes were more severe at 8 weeks in the EPO group compared to black cohosh. The current evidence is insufficient to draw firm conclusions regarding the benefits of EPO in alleviating hot flashes. We hope that more research is conducted to provide sufficient evidence for menopausal women considering the use of EPO.