Topline results from Novo Nordisk’s phase 3 STEP Young trial indicate that weekly semaglutide was associated with a substantial reduction in obesity among children aged 6 to under 12. After 68 weeks, 40.4% of children receiving the medicine were no longer classified as having obesity, compared with none of those given a placebo.

The trial enrolled 165 children. Participants in both groups also followed a reduced-calorie diet and were asked to increase their physical activity, meaning the results reflect semaglutide treatment alongside those lifestyle interventions.

What the trial found

Children who received semaglutide achieved a greater reduction in body mass index than those in the placebo group, according to the topline findings. The treatment group was assigned a maximum weekly dose of either 1.7 milligrams or 2.4 milligrams, depending on participants’ starting weight.

The reported classification result was one of the clearest differences between the groups. While 40.4% of children treated with semaglutide were no longer classified as having obesity at the end of the 68-week treatment period, the corresponding figure in the placebo group was zero.

More than 85% of the participants had class II or class III severe obesity when they entered the study. The trial therefore included a population with a high level of obesity at the outset, rather than children with less severe weight-related conditions alone.

The findings come from a phase 3 study, but the currently available information consists of topline results. Further details on the participants’ outcomes and the full analysis are expected to be presented at Obesity Week 2026 in Washington, D.C.

Safety and development

Novo Nordisk reported that the trial identified no new safety concerns related to growth or pubertal development. The available findings do not provide additional detail on other safety outcomes or on how the results differed between the two semaglutide dose levels.

Growth and pubertal development are important considerations in studies involving young children. The company’s statement on these outcomes addresses the areas specified in the topline report, while the broader safety profile is expected to be assessed in the detailed results.

Semaglutide was administered once a week during the 68-week trial period. Both the medicine and placebo groups received the same general diet and physical-activity interventions, allowing the reported comparison to focus on the difference associated with the treatment group in the study.

Detailed findings due at Obesity Week 2026

The STEP Young results add evidence from children aged 6 to under 12 to research into semaglutide and obesity treatment. However, the full significance of the findings will depend on the detailed data expected at the upcoming conference, including the complete BMI results, safety information and other trial outcomes.

For now, the topline results show a marked difference in obesity classification after 68 weeks: 40.4% of children receiving semaglutide were no longer classified as having obesity, compared with none in the placebo group. The study was conducted with diet and increased physical activity as part of care in both groups.