Isoflavones improve vaginal atrophy, skin health, and sex-related hormones in postmenopausal women: a systematic review and meta-analysis of randomized controlled trials.

IMPORTANCE

Isoflavones, natural bioactive compounds with estrogen-like properties, are increasingly used by postmenopausal women to manage menopausal symptoms. However, research on their efficacy has produced inconsistent results, necessitating a comprehensive review to guide clinical practice.

OBJECTIVE

To evaluate the effects of isoflavone interventions on vaginal atrophy, skin health, and sex-related hormone levels in postmenopausal women through a systematic review and meta-analysis of randomized controlled trials.

EVIDENCE REVIEW: A systematic literature search was conducted in PubMed, Embase, Scopus, and the Cochrane Library databases from inception to January 2025. Eligible studies were randomized controlled trials investigating isoflavone interventions in postmenopausal women. Effect sizes were summarized as standardized mean differences (SMDs) with 95% CIs using a random-effects model. The risk of bias was assessed using the Risk of Bias 2 tool.

FINDINGS: The analysis included 47 studies comprising 2,657 participants. Isoflavone interventions significantly reduced vaginal dryness (SMD=-1.147; 95% CI, -2.077 to -0.216; P =0.016; I2 =95.4%) and increased the vaginal maturation value (SMD=0.605; 95% CI, 0.087 to 1.123; P =0.022; I2 ​​​​​​=88.7%). Improvements in skin health were observed, including reduced skin roughness measure R2 (SMD=-0.209; 95% CI, -0.389 to -0.029; P =0.028; I²=0.0%) and wrinkle surface (SMD=-0.342; 95% CI, -0.560 to -0.124; P =0.002; I2 =0.0%). Isoflavones also significantly increased estradiol levels (SMD=0.247; 95% CI, 0.059 to 0.435; P =0.010; I2 =60.5%).

CONCLUSIONS AND RELEVANCE: Isoflavone interventions effectively manage vaginal atrophy in postmenopausal women and show potential for improving skin health and sex-related hormone levels. These findings underscore the therapeutic value of isoflavones while emphasizing the need for further research, particularly regarding their effects on skin health.