GLP-1 Drugs May Work Differently in Women

A systematic review and meta-analysis of randomized trials found that women lost more weight than men while taking GLP-1 receptor agonists. In six trials with nearly 20,000 participants whose outcomes were analyzed by sex, women lost an average of 10.88% of their starting weight, compared with 6.8% for men. Differences in estrogen, body composition, drug processing, or women’s lower average body weight could help explain the gap, but the analysis did not establish a mechanism. Weight-loss effects were otherwise broadly similar across groups defined by age, race, ethnicity, starting BMI, and HbA1c.

Researchers reviewed 64 randomized trials reported in 41 publications, with follow-up ranging from 12 to 144 weeks; nearly all trials were industry-funded. Most examined semaglutide, while other included drugs included liraglutide, dulaglutide, and exenatide. Subgroup results by sex were available for only a small share of trials, and more studies are needed to clarify why women may respond differently and how well trial findings apply to routine care, especially for groups under-represented in research. The review’s search covered studies published through July 2024 and did not include tirzepatide, a dual GIP/GLP-1 drug. The findings point to sex as a potentially important factor in weight-loss response, while offering little evidence that other commonly studied patient characteristics substantially alter treatment effects.