Impact of evening primrose oil consumption on psychological symptoms of postmenopausal women: a randomized double-blinded placebo-controlled clinical trial

OBJECTIVE: The purpose of this study was to determine the efficacy and safety of evening primrose oil on women's psychological symptoms during menopause. METHODS: A double-blinded randomized placebo-controlled trial carried out from September 2018 to February 2019 in Bandar Abbas, Iran. Eligible women randomly received either 1,000 mg of evening primrose oil capsules daily or matching placebo for 8 weeks. The Main outcome measures were psychological symptoms based on the psychological subscale of the Menopause Rating Scale. Independent samples t test was used for intergroup comparisons and paired samples t test for pre- and post-treatment comparisons. P ≤ 0.05 was considered statistically significant. RESULTS: The 8-week treatment was completed by 189 women. The mean baseline psychological score did not differ among the two groups. After intervention, the psychological score, however, differed significantly among groups (P < 0.01). To distinguish the effect of evening primrose oil, we compared the reduction in the psychological score in each group. Regarding mean differences of the psychological score in both groups, there was a prominent alleviation in the intervention group mean difference: -3.44 (95% confidence interval of difference: -4.01 to -1.20) (P < 0.01). In addition, only one patient reported gastric upset in the intervention group. CONCLUSIONS: This study could provide evidence regarding the potential benefits of evening primrose oil for the psychological symptoms of postmenopausal women. Longer trials are necessary to make more reliable decisions about the use of evening primrose oil and its safety in clinical practice.