In the STEP trials of semaglutide, women lost markedly more weight than men on the same drug — 14.0% versus 8.0% of body weight in one trial, 16.2% versus 9.3% in another (Börchers & Skibicka, Endocrinology, 2025, DOI (external link), via PubMed). GLP-1 medications aren't sex-neutral. They tend to work harder in women, come with more side effects in women, and are even absorbed differently between the sexes — and some of that traces to estrogen and testosterone. Here's what the evidence actually shows, and what it means for what you should expect.
Women tend to lose more weight
Across GLP-1 analogs, women lose more weight than men on average. In the semaglutide STEP program the gap was consistent: 14.0% vs 8.0% (STEP 1), 7.5% vs 4.6% (STEP 2), and 16.2% vs 9.3% (STEP 4), women versus men respectively (Börchers & Skibicka, Endocrinology, 2025, DOI (external link), via PubMed).
The obvious guess — women are smaller, so a standard dose goes further — isn't the whole story. At the same body weight, women had about 32% higher drug exposure than men on liraglutide, and the review notes that even women who weighed more than the men still lost more. So it's not simply body size; the drug appears to do more per milligram in women.
Side effects hit women harder
The flip side of a stronger response is worse tolerability. Women report and discontinue for side effects considerably more often:
- Nearly 50% more women than men discontinued treatment overall.
- Twice as many women stopped specifically because of gastrointestinal side effects.