An interventional study of Semaglutide (SEMA) and Placebo in Caloric Restriction, Body Composition and Performance, sponsored by Morten Hostrup, PhD. Not yet recruiting at 1 site in Denmark. Open to participants aged 18 Years to 45 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-10-15.
Sponsored by Morten Hostrup, PhD · Not applicable, Interventional, and Basic science
Semaglutide, a GLP-1 receptor agonist, has demonstrated significant weight-loss effects in people with obesity and/or type 2 diabetes, but its impact on exercise performance among lean, fit athletes remains unknown. This randomized placebo-controlled parallel intervention study aims to investigate the short-term effects of semaglutide on body composition, muscle mass, volume and function, running economy, and performance in well-trained male and female runners.
Healthy experienced triathletes or distance runners will complete a 4-week intervention with either weekly injections of semaglutide (0.25 mg) or placebo. Before and after the intervention period, participants will complete 2 experimental days (4 experimental days in total). On experimental days, change in body composition, with a particular focus on muscle mass, will be assessed using DXA scans and ultrasound imaging of v. lateralis. Furthermore, specific performance tests (200-m, 3-km, 10-km) as well as running economy will be measured.
Morten Hostrup, PhD is the lead sponsor of 17 studies on the registry; 7 are open to participants now.
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Exclusion Criteria:
For female participants, additional exclusion criteria are
Participants will receive semaglutide treatment for 4 weeks
Drug: Semaglutide (SEMA)
Participants will receive placebo treatment for 4 weeks
Drug: Placebo
Participants will receive a 4-week semaglutide treatment with subcutaneous injections of 0.25 mg once weekly.
Participants will receive a 4-week placebo treatment with subcutaneous injections once weekly.
Change in total lean mass measured by dual-energy X-ray absorptiometry (DXA)
Total lean mass will be assessed using dual-energy X-ray absorptiometry (DXA). The change in total lean mass from baseline to the end of the 4-week intervention period will be calculated (unit of measure: kilograms (kg)).
Time frame: Baseline (week 0) and immediately after the 4-week intervention period (week 4)
Change in muscle thickness measured by ultrasonography
Muscle thickness will be assessed by ultrasonography at predefined anatomical sites. The change in muscle thickness from baseline to the end of the 4-week intervention period will be calculated (unit of measure: millimeters (mm)).
Time frame: Baseline (week 0) and immediately after the 4-week intervention period (week 4)
Change in running performance
Running performance will be assessed using 200-m, 3-km and 10-km running performance tests, as well as running economy.
Time frame: Baseline (week 0) and immediately after the 4-week intervention period (week 4)
Change in maximal voluntary isometric quadriceps contraction torque
Maximal voluntary isometric contraction torque of the quadriceps muscles will be assessed using an isometric strength test. The change in maximal isometric contraction torque from baseline to the end of the 4-week intervention period will be calculated (unit of measure: newton-meters (N\*m)).
Time frame: Baseline (week 0) and immediately after the 4-week intervention period (week 4)
Change in one-repetition maximum (1RM) leg press strength
Lower-body muscle strength will be assessed using a one-repetition maximum (1RM) leg press test. The change in 1RM leg press strength from baseline to the end of the 4-week intervention period will be calculated (unit of measure: kilograms (kg)).
Time frame: Baseline (Week 0) and immediately after the 4-week intervention period (Week 4).
Plan to share: No
No publications or documents are linked to this record.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
This study is not yet recruiting, as verified in Oct 2026. You cannot join it, but the record below documents what was studied.
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Studies of the drug tested here: Semaglutide
Morten Hostrup, PhD