Short Term Effects of Semaglutide on Body Composition and Performance

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.

Inclusion Criteria: * Healthy experienced triathletes or distance runners (training history +5 years and weekly training volume \>10 h/week) * Aged 18 to 45 years * Body mass index (BMI) between 21.0-26.0 kg/m2 Exclusion Criteria: * Chronic use of medication (except for occasional use of analgesics or antihistamines) * Chronic disease (e.g. diabetes, disordered eating behavior (EDE-Q \>2.5 for females and 1.7 for males)) * Abnormal kidney function, or ECG abnormalities. For female participants, additional exclusion criteria are * Pregnancy * Current or recent use of any hormonal contraceptives the last 6 months (including oral contraceptives, hormonal implants, injectable contraceptives, and hormone-releasing intrauterine devices) * Irregular menstrual cycles (cycle length outside the 21-35-day range) and anovulatory cycles