JOULE - Metabolic Adaptation to Weight Loss in Response to a Behavioural Lifestyle Program With or Without Semaglutide in Adolescents With Obesity

What Was Tested

This registered phase 4 trial tested Semaglutide for fat loss, obesity & body recomposition.

The Joule MARS study is a single center, randomized, open label clinical trial aiming to explore the metabolic adaptations that occur in response to weight management in adolescents with obesity.

Study participants will be randomized to one of two groups.

It had two arms (groups): BLP, then BLP+semaglutide (active comparator) and BLP and semaglutide (experimental).

The registry classes the interventions as behavioral and drug.

More on the Plan

The study will involve two intervention groups: Group A will participate in a behavioral lifestyle program (BLP) alone for 6 months followed by a combination of semaglutide treatment and a BLP for an additional 6 months.

Group B will receive semaglutide and a BLP for the first 6 months and then terminate the study.

A comprehensive assessment will be conducted throughout the study.

Using whole-room indirect calorimetry, REE and muscle work efficiency, evaluated during standardized physical activity on a cycle ergometer, will be measured.

Who Took Part

74 planned participants were the target.

It was open to people of any sex aged from 12 years up to 17 years.

Healthy volunteers were not accepted; participants needed the condition being studied.

Examples of who could join: Youth aged 12-17 years. Diagnosed with obesity (BMI ≥2 standard deviations above WHO Reference median).

The full record lists 3 inclusion and 15 exclusion criteria; among the exclusions: any contraindications for mri (i.e. claustrophobia, implanted metal, metallic injuries recent tattoo or weight \>300lb. ineligible for imaging visit only; use of atypical anti-psychotics; elevated alanine aminotransferase (alt) \> 5 x upper range of normal at screening.

How the Study Was Run

It was run as a randomized, parallel-group and open-label study.

Random assignment meant chance, not the researchers, decided who got Semaglutide and who got the comparison, which limits bias.

Groups ran in parallel: each of the fat loss, obesity & body recomposition participants stayed in one arm throughout.

Being open-label, the Semaglutide study did not mask who received what.

It started in 2025-06-18 with completion listed for 2027-12-31.

It ran at 1 site in Canada.

Its stated primary purpose is treatment.

What Was Measured

Primary outcome: Measurement of Adaptive thermogenesis (time frame: 6, 12 months).

It also tracked 10 secondary outcomes, for example Changes in energy work efficiency from baseline during standardized exercise, Brown Adipose Tissue (BAT) activity, Total body mass, fat mass and lean mass, Hepatic fat content, Hepatic stiffness and Fasting lipid profile.

What This Means in Plain Language

Put simply, this is a phase 4, randomized trial of Semaglutide in 74 people with fat loss, obesity & body recomposition.

It is still recruiting; no results are posted to the registry yet, so nothing here describes outcomes.

More context: the Semaglutide compound page, Fat loss, obesity & body recomposition research.