New research indicates that women lose more weight than men when using GLP-1 receptor agonists, a class of medications employed for weight management. In a study involving 1,000 patients treated with the drug Mounjaro (tirzepatide) for over a year, women experienced an average body weight reduction of 15%, compared with nearly 11% for men after 15 months of continuous treatment.

The study categorized participants into three age groups—under 45, between 46 and 59, and 60 or older—and found that while younger patients tended to lose more weight overall, age was not the most significant predictor of weight loss. Patients under 45 lost approximately 15% of their body weight, versus 12% among those over 60. Beyond sex and age, greater weight loss was also associated with not having Type 2 diabetes, not having previously used weight-loss medications, and receiving higher doses of tirzepatide.

Women have generally faced more difficulties losing weight due to factors such as lower muscle mass, hormonal changes, and differences in fat distribution. However, multiple studies now suggest that GLP-1 drugs may offer comparatively greater benefits for women. A meta-analysis of nearly 20,000 individuals treated with related medications, including semaglutide and dulaglutide, showed women lost about 11% of their body weight on average, compared to roughly 7% for men.

Researchers have proposed several explanations for these sex-based differences in effectiveness. One is that women metabolize GLP-1 drugs more slowly, leading to prolonged drug activity. Additionally, hormonal factors, particularly the role of estrogen, may amplify the drugs’ effects by influencing appetite regulation, satiety, energy expenditure, and insulin sensitivity.

Furthermore, emerging evidence suggests that the advantages of GLP-1 receptor agonists for women could extend beyond weight loss. Some studies have noted a potential reduced risk of breast cancer among female users of these medications, although further research is needed to confirm and clarify this finding.

Overall, these findings contribute to a growing understanding of how GLP-1 receptor agonists work differently across sexes and may inform more tailored weight management approaches in the future.