A new randomized controlled trial indicates that integrating supervised resistance exercise with tirzepatide therapy preserves lean muscle mass in middle-aged and older adults with obesity.
The 40-week study, led by investigators at the University of Western Australia, compared the outcomes of participants receiving weekly tirzepatide injections alone against those who combined the medication with three sessions of center-based, progressive resistance exercise training per week.
Men and Women Aged 50 to 70 Participated in the Study
The Tirzepatide and Resistance Exercise (T-REx) study focused on community-dwelling men and postmenopausal women between the ages of 50 and 70. To be eligible, participants were required to have a body mass index (BMI) of at least 30 kg/m², or a BMI of at least 27 kg/m² alongside at least one weight-related comorbidity, such as hypertension, dyslipidemia, or obstructive sleep apnea.
Investigators specifically targeted individuals who reported less than 60 minutes of moderate or higher intensity exercise per week in the three months prior to enrollment.
The trial utilized a 1:1 randomization process to assign participants into two parallel groups. While the study protocol was pre-registered in the Australian New Zealand Clinical Trials Registry, it excluded individuals with a history of diabetes mellitus, cardiovascular disease, pancreatitis, or previous bariatric surgery.
Participants were also required to be willing to commit to up to 150 minutes of exercise per week as part of the center-based program. An approved 26 February 2024 addition stipulated that should participants be unable to attend the campus for injections, such as while on holidays, they could self-administer the drug off-site.
The Research Team Managed Study Aspects and Safety Monitoring
The research team independently organized all aspects of the study, including participant recruitment, data collection, and analysis. Eli Lilly provided the tirzepatide for the investigator-initiated trial and reviewed the final manuscript to ensure no intellectual property or new safety issues were identified, though the company had no role in the conduct of the research.
Safety was a continuous priority throughout the 40-week intervention. Research nurses monitored participants during their weekly visits for tirzepatide injections, and an independent committee—comprising an endocrinologist, a pharmacist, and an exercise physiologist—reviewed any reported adverse events.
According to the T-REx trial design, any events of concern were referred to medically qualified investigators for formal review. Under FDAAA 801 requirements, the study record remains subject to strict submission rules, where records cannot be modified following submission until a quality control review is finalized, unless the submission is canceled.
