Effects of different Metabolic Bariatric Surgeries in Testosterone Levels: A Systematic Review and Meta-Analysis.

Obesity, a globally prevalent condition associated with various comorbidities, has significant impacts on male endocrine health, including alterations in testosterone levels. Metabolic Bariatric Surgery stands out as an effective approach to promoting weight loss and improving hormonal outcomes. This study aims to evaluate and compare the effects of Roux-en-Y gastric bypass (RYGB) and Laparoscopic Sleeve Gastrectomy (LSG) or Laparoscopic adjustable gastric banding (LAGB) on testosterone levels in men. This systematic review and meta-analysis followed the Cochrane Handbook and PRISMA guidelines, registered under Id no. CRD42025633946, approved on Jan 29, 2025, in the Prospective International Registry of Systematic Reviews (PROSPERO). The search was conducted in Medline, Embase, and Web of Science platforms (up to July 2024) focused on studies comparing RYGB and LSG or LAGB and reporting pre- and post-surgery testosterone levels. Data on patients, interventions, and outcomes were extracted, and statistical analyses employed random-effects models and heterogeneity assessment. The combined analysis showed a mean difference of 113.07 ng/dL (95% CI: 1.47 to 224.67) favoring RYGB, with high heterogeneity (I² = 65%). Individual studies suggest a greater increase in testosterone levels in the RYGB group. This review suggests that RYGB may lead to a significant increase in testosterone levels, but the results should be interpreted cautiously due to study limitations and variability, and future studies with larger samples and standardized protocols are needed.