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 long-term effects of semaglutide on body composition, muscle mass, volume and function, running economy, and performance as well as on hormonal markers in well-trained male and female runners.
Healthy experienced triathletes or distance runners will complete a 12-week intervention with either weekly injections of semaglutide (titrated from 0.25 and up to 1.0 mg) or placebo. Furthermore, participants will complete a follow-up period consisting of 4 weeks without treatment. Before and after the intervention period as well as the follow-up period, participants will complete 2 experimental days (6 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. In addition, specific performance tests (200-m, 3-km, 10-km) and running economy, as well as hormonal markers in serum and urine will be measured.
Morten Hostrup, PhD is the lead sponsor of 17 studies on the registry; 7 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
For female participants, additional exclusion criteria are
Participants will receive semaglutide treatment for 12 weeks. This will be followed by a 4-week follow-up period without treatment.
Drug: Semaglutide (SEMA)
Participants will receive placebo treatment for 12 weeks. This will be followed by a 4-week follow-up period without treatment.
Drug: Placebo
The semaglutide group will receive subcutaneous injections with semaglutide, titrated from 0.25 mg up to 1.0 mg once weekly in accordance with standard treatment guidelines (dose increasing every 4 week). After the 12-week intervention period, participants will complete a 4 week follow-up period without treatment.
The placebo group will receive subcutaneous injections with placebo once weekly. After the 12-week intervention period, participants will complete a 4 week follow-up period without treatment.
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), immediately after the 12-week intervention period (week 12), and immediately after the 4-week follow-up period without treatment (week 16).
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), immediately after the 12-week intervention period (week 12), and immediately after the 4-week follow-up period without treatment (week 16).
Change in running performance
Running performance will be assessed using 200-m, 3-km and 10-km running performance as well as running economy and VO2max during an incremental test on treadmill.
Time frame: Baseline (week 0), immediately after the 12-week intervention period (week 12), and immediately after the 4-week follow-up period without treatment (week 16).
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), immediately after the 12-week intervention period (week 12), and immediately after the 4-week follow-up period without treatment (week 16).
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), immediately after the 12-week intervention period (week 12), and immediately after the 4-week follow-up period without treatment (week 16).
Changes in serum and urinary steroidal and endocrine biomarkers
Serum and urine concentrations of prespecified steroidal and endocrine biomarkers will be measured. Changes in biomarker concentrations from baseline will be assessed following the 12-week intervention and following the 4-week treatment-free follow-up period. Biomarkers will be analyzed individually and reported using their respective units of measurement.
Time frame: Baseline (week 0), immediately after the 12-week intervention period (week 12), and immediately after the 4-week follow-up period without treatment (week 16).
Plan to share: No
No publications or documents are linked to this record.
Start is estimated for Oct 2026; primary completion for Dec 2027, 14 months later.
How these figures are worked out, and which studies are left out of them.
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.
Get an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.
Studies of the drug tested here: Semaglutide
Morten Hostrup, PhD