Study wrapper · #339
Effect of bremelanotide on body weight of obese women: Data from two phase 1 randomized controlled trials.
Editor's note
These are two small Phase 1 randomized, placebo-controlled trials testing an off-label question: whether bremelanotide's (PT-141) activity at the MC4 receptor — a hub of appetite regulation — reduces food intake and body weight in premenopausal women with obesity. Researchers reported statistically significant reductions in weight (about 1.3 kg over 16 days in Study A) and roughly 400 kcal/day lower intake versus placebo. Mechanistically this is coherent, since MC4R agonism promotes satiety. But weigh it cautiously. These are Phase 1 trials, very short (4–16 days), small (30 and 27 subjects), and dosed far more frequently than the approved on-demand HSDD protocol, so they speak to a short-term signal, not durable weight change. Study B lost nearly half its participants. Bremelanotide is not developed or approved for weight management, and these early findings do not establish a meaningful or lasting effect. Longer human trials would be needed.
Plain-language abstract
The MC4 receptor in the brain helps control appetite, and switching it on tends to make people feel full. Because bremelanotide (PT-141) activates this receptor, researchers ran two short early-stage trials to see whether it affects eating and weight in premenopausal women with obesity. In the first trial, 30 women received either bremelanotide or a placebo injection three times daily for about two weeks; in the second, 27 women cycled through different doses in short 4-day periods. The team tracked weight and food intake every day and monitored for side effects, though the abstract does not detail them. Women on bremelanotide lost more weight than those on placebo — about 1.3 kg over 16 days in the first study — and ate roughly 400 fewer calories per day. The second trial showed a similar pattern with twice-daily dosing, though nearly half the participants did not complete it. The authors conclude that activating MC4R may reduce calorie intake, but these were brief, small studies.