The efficacy of oral Lavandula angustifolia Mill. essential oil on menopausal symptoms, serum lipid profile, and cortisol concentration in postmenopausal women: A triple-blind, randomized, controlled trial

Objective: To determine the effect of oral Lavandula angustifolia Mill. essential oil (LEO) on menopausal symptoms, serum cortisol level, and lipid profile in postmenopausal women. Methods: This was a triple-blind parallel-armed randomized trial. Seventy-two postmenopausal women aged 50-65 years referring to healthcare centers in Tabriz, Iran with a score of 15-42 on the Green scale were included from May 10, 2022 to May 22, 2023. The participants were randomly assigned to two groups with a 1:1 ratio and using four and six blocks. One group received LEO soft gel 80 mg per day, and another group received a similar placebo for 60 days. A demographic questionnaire and a Greene menopause symptom scale were used for data collection. The lipid profile (total cholesterol, triglyceride, LDL, HDL) and the serum levels of cortisol were measured using biochemical methods. Chi-square, Fisher's exact tests, Independent samples t-test, Analysis of Covariance (ANCOVA), Repeated measure ANOVA, and Paired sample t-test were utilized for analyses. A p-value less than 0.05 was considered statistically significant. Results: The demographic and personal characteristics of the participants were similar. After two months of intervention, all symptoms in psychological, physical, vasomotor, anxiety, depression, and sexual dysfunction domains were significantly relieved (decreased) among both groups (p < 0.003), except for sexual dysfunction, the reduction of which was not significant in the placebo group (p = 0.317). The mean (SD) total score of menopausal symptoms reduced from 27.4 (6.3) at baseline to 17.7 (4.9) at the end of the study in the LEO group (p < 0.001). It also decreased from 27.4 (7.1) to 17.6 (5.1) in the placebo group (p < 0.001). However, between-group analyses revealed that this reduction was significantly greater in the LEO group compared to the placebo group only in the sexual dysfunction (Mean (SD): 1.3 (0.6) vs. 1.0 (0.5); adjusted mean difference (95% confidence interval); p: - 0.35 (-0.67 to -0.02); 0.039). No significant within-group changes or between-group differences were observed (p > 0.05) in terms of studied serum markers. Conclusion: The oral LEO exhibited a significant enhancement in sexual dysfunction among postmenopausal women. Therefore, it can be used alongside other therapies to improve sexual dysfunction during menopause. LEO did not affect lipid profile and serum cortisol level in this study.