Semaglutide in teens: who responds best?

A new letter published in Diabetes, Obesity & Metabolism on 3 June 2026 examines which adolescents respond best to semaglutide for obesity, using real-world clinical data rather than the controlled conditions of a randomised trial^[1]. The study, led by Valeria Cimador and Rebecca J. Moon, tracks treatment outcomes outside the strict inclusion criteria that defined the STEP TEENS programme, and asks the question clinicians face daily: once you move past trial populations, who benefits most?

What STEP TEENS established

The foundation here is STEP TEENS (Weghuber et al., NEJM 2022), the double-blind, placebo-controlled trial that led to regulatory approval of semaglutide 2.4 mg weekly for adolescents aged 12 and older with obesity^[2]. In 201 participants, semaglutide produced a mean BMI reduction of 16.1% at 68 weeks, compared with a 0.6% increase on placebo. Seventy-three percent of the semaglutide group achieved at least 5% weight loss. The FDA approved Wegovy for adolescents in December 2022; the EMA authorised the same indication under the Wegovy label in January 2022, later extended to adolescents aged 12 and above^[3].

Those numbers are striking, but they come from a carefully selected population with structured lifestyle support and close follow-up. Clinicians prescribing semaglutide to adolescents in routine care see a wider range of patients, with varied adherence, different comorbidity profiles, and less controlled follow-up schedules. The question of who responds well outside a trial setting is not answered by the trial itself.

Why real-world predictors matter

The Cimador et al. letter addresses this gap. Real-world data studies track patients as they present in clinical practice, with varied adherence, comorbidity profiles, and follow-up timelines. For adult populations, predictor studies have begun to map out response patterns. A 2026 secondary analysis of STEP TEENS data found that semaglutide improved insulin sensitivity (HOMA-IR reduced by 35.0% versus 5.3% on placebo) and cardiometabolic markers in adolescents regardless of baseline metabolic status^[4]. But that analysis still drew on trial data. What Cimador and colleagues add is the observational layer: real patients, real clinics, real variation in response.

Separately, CDC data published in 2025 showed that prescriptions for obesity medications among US adolescents aged 12 to 17 rose by roughly 300% between 2020 and 2023, with semaglutide accounting for 57.1% of those prescriptions. Girls were twice as likely to receive a prescription as boys, and Black adolescents were 39% less likely to be prescribed than White adolescents despite higher rates of severe obesity. That prescribing context makes predictor research more urgent: as more adolescents receive these drugs, knowing who responds well (and who does not) shapes both clinical decisions and equity conversations.

What we do not yet know

The Cimador et al. paper is published as a letter in Diabetes, Obesity & Metabolism, not a full-length original article. PubMed lists it without an abstract, and the full text is behind a paywall at the time of writing. That means the specific predictors identified, the sample size, the follow-up duration, and the effect sizes are not yet publicly summarised in a way we can independently verify and report here. We will update this article when the full text becomes accessible or the authors present the findings at a conference.

More broadly, predictors of GLP-1 response in adolescents remain undercharacterised. In adults, early weight-loss response (the first 8 to 12 weeks) is the strongest predictor of long-term outcomes. Whether that pattern holds in adolescents, whose metabolic and developmental trajectories differ meaningfully from adults, is an open question. Puberty, growth velocity, hormonal shifts, and the psychological context of weight management in teenage years all complicate the picture. Sex-based differences in prescribing and in physiological response also need more data before clinicians can confidently stratify who benefits most.

Where this fits for readers

If you are a parent, a clinician, or an adolescent researching semaglutide, the Cimador et al. paper is a signal that the field is moving from "does this drug work in teens?" (answered by STEP TEENS) to "which teens benefit most, and what should clinicians watch for?" That second question is where real-world data earns its keep.

This article is for educational purposes. Any decision about starting, adjusting, or stopping semaglutide in an adolescent belongs with the prescribing clinician who knows the individual case. Consult a healthcare professional before acting on anything you read here.