This systematic review and meta-analysis aimed to examine the effect of the antioxidant alpha-lipoic acid (ALA) on various cardiometabolic risk factors and hormonal parameters in patients with polycystic ovary syndrome (PCOS). We searched PubMed, EMBASE, SCOPUS, Cochrane Library, and Web of Science databases without language restrictions until May 2023 to find randomized controlled trials (RCTs) that assessed the impact of ALA supplementation on anthropometric, glycemic, lipid, oxidative stress, and hormonal parameters in women with PCOS. Outcomes were summarized using the standardized mean difference (SMD) and 95% confidence interval (CI) in a random-effects model. An I2 statistic of >60% established significant between-study heterogeneity. The overall certainty of the evidence for each outcome was determined using the grading of recommendations, assessment, development, and evaluations system. Seven RCTs met the inclusion criteria. The ALA group had significant reductions in fasting blood sugar (fasting blood sugar (FBS), n=7 RCTs, SMD, -0.60; 95% CI, -1.10 to -0.10; I2=63.54%, moderate certainty of evidence) and homeostatic model assessment for insulin resistance (homeostatic model assessment of insulin resistance (HOMA-IR), n=4 RCTs, SMD, -2.03; 95% CI, -3.85 to -0.20; I2=96.32%, low certainty of evidence) compared with the control group. However, significant differences were observed between the groups in body mass index, insulin, estrogen, follicle-stimulating hormone, luteinizing hormone, testosterone, low-density lipoprotein, highdensity lipoprotein, triglyceride, total cholesterol, malondialdehyde, or total antioxidant capacity profiles. ALA supplementation improves FBS and HOMA-IR levels in women with PCOS. ALA consumption is an effective complementary therapy for the management of women with PCOS.

This study aimed to review randomized controlled trials (RCTs) investigating the effects of dietary antioxidant supplements on the severity of endometriosis-related pain symptoms. The PubMed/Medline, Scopus, and Web of Science databases were searched until April 2022. Additionally, we manually searched the reference lists. Endpoints were summarized as standardized mean difference (SMD) with 95% confidence intervals (CIs) in a random-effects model. The I2 statistic was used to assess heterogeneity. Ten RCTs were included in this meta-analysis. Overall, 10 studies were related to dysmenorrhea, four to dyspareunia, and four to pelvic pain. Antioxidants significantly reduced dysmenorrhea (SMD, -0.48; 95% CI, -0.82 to -0.13; I2=75.14%). In a subgroup analysis, a significant reduction of dysmenorrhea was observed only in a subset of trials that administered vitamin D (SMD, -0.59; 95% CI, -1.13 to -0.06; I2=69.59%) and melatonin (SMD, -1.40; 95% CI, -2.47 to -0.32; I2=79.15%). Meta-analysis results also suggested that antioxidant supplementation significantly improved pelvic pain (SMD, -1.51; 95% CI, -2.74 to -0.29; I2=93.96%), although they seem not to have a significant beneficial impact on the severity of dyspareunia. Dietary antioxidant supplementation seems to beneficially impact the severity of endometriosis-related dysmenorrhea (with an emphasis on vitamin D and melatonin) and pelvic pain. However, due to the relatively small sample size and high heterogeneity, the findings should be interpreted cautiously, and the importance of further well-designed clinical studies cannot be overstated.