| Trial results
Lilly says tirzepatide (Zepbound) reduced body mass index, or BMI, by an average of 21.4% in adolescents aged 12 to under 18 with obesity at 72 weeks in the phase 3 SURMOUNT-ADOLESCENTS trial, and that more than half no longer met the BMI criteria for obesity. These are preliminary, company-reported figures from a press release. The release does not say whether 21.4% is the change in the tirzepatide group or the gap from placebo, and it gives no number of participants, no placebo result and no safety data.
What was reported
| Question | What Lilly's release says |
|---|---|
| Average change in BMI | Zepbound reduced BMI by an average of 21.4% in adolescents aged 12 to under 18 with obesity, at 72 weeks |
| No longer meeting the BMI criteria for obesity | More than half, at 72 weeks. No exact figure |
| Quality of life | Participants reported improvements in weight-related quality of life, including physical comfort and body esteem. No scores |
| Whether 21.4% is the change on tirzepatide or the gap from placebo | Not stated |
| Result in the placebo group | Not stated |
| Number of participants, and how many finished | Not stated |
| Weight in kilograms or BMI in points | Not stated |
| Side effects, serious side effects, stopping treatment | Not stated |
| Which doses | Not stated |
Company-reported, from Lilly's release of November 14, 2026.
BMI is not the same as weight
Adults are usually judged by percent weight change. Adolescents are still growing, so a drop in BMI can come from losing weight, from growing taller, or both. A 21.4% fall in BMI is therefore not the same as 21.4% weight loss, and it should not be lined up against the weight-loss figures from adult trials. In young people, obesity is defined against growth charts, using BMI for age and sex.
What the trial tested
SURMOUNT-ADOLESCENTS (NCT06075667) is a randomized, double-blind, placebo-controlled phase 3 trial, according to ClinicalTrials.gov. The record lists 160 participants aged 12 to 17, with obesity or with overweight and at least one weight-related condition. The main goal is the percent change in BMI at week 72. Secondary goals include body weight, waist size, blood pressure, blood fats and blood sugar, and there is an optional extension to 156 weeks. The record lists about 25 sites in the U.S., Canada, Czechia, Israel, Italy and Poland, a primary completion date of June 2026 and a study completion date of July 2029. Lilly's release does not give any of these details.
Where this stands for approval
Zepbound is approved for adults. Lilly's own safety summary in the same release still says it is not known whether Zepbound is safe and effective in children. The Atlas has not found an FDA approval of tirzepatide for anyone under 18, and the release mentions no filing. Two other weight-loss medicines are approved for ages 12 and up: semaglutide (Wegovy) and liraglutide (Saxenda).
What to watch for
Lilly lists the adolescent result under its Retatrutide and Zepbound oral session at ObesityWeek on Sunday, November 15, from 5:00 to 6:30 p.m. ET, a session it says will present phase 3 results. The things that would turn this headline into evidence are the placebo comparison, the number of people who finished, how many stopped treatment and why, and safety in a growing population. The Atlas will update this page when fuller data appear.
Worth knowing: This is a company-reported headline from a press release, with no placebo comparison, group size or safety data. Zepbound is not approved for people under 18. Decisions about weight-loss medicines for a young person belong with their doctor. This page is general information, not medical advice.
Related: Tirzepatide medicine page | Lilly tracker
Source: Lilly press release, November 14, 2026 Company announcement, not peer reviewed. ClinicalTrials.gov record NCT06075667 Trial registry.