Combining tirzepatide with resistance training can reduce muscle mass loss and increase strength in people using weight-loss medication, according to a phase 3 clinical trial.
The Tirzepatide and Resistance Exercise (T-REx) study, a 40-week trial involving 120 participants, found that resistance training helped preserve lean tissue and improved physical strength during treatment with the GLP-1 medicine, as published in Nature Medicine.
Resistance training mitigates muscle loss
Participants in the study included 60 men and 60 postmenopausal women aged 50 to 70 who were obese, or overweight with a weight-related health issue. While all participants experienced rapid weight loss from the tirzepatide injections, those who performed three supervised resistance training sessions per week saw different body composition outcomes than the untrained group, Miragenews reported.
Those who engaged in resistance training lost 25 per cent less lean tissue, which includes muscle, bones, and organs, compared to those who did not exercise. Professor Green noted that the goal for those taking weight-loss drugs should be to improve their health and function, not just a lower number on the scales.
With GLP-1 medicines now widely used and reducing body weight by an average of 20-25 per cent, and more than that in many people, it’s crucial that we understand how best to achieve optimal body composition and health in the weight-reduced state,
Professor Green said.
Strength gains versus declines
The trial also measured the impact of exercise on physical capability. Resistance training participants saw their upper and lower body strength improve by 10 per cent. In contrast, strength declined by 10 per cent in the group that took tirzepatide without resistance training.
| Group | Average weight loss (kg) | Average fat mass loss (kg) | Strength change |
|---|---|---|---|
| Resistance training group | 22.28 | 17.98 | 10 per cent improvement |
| Untrained group | 22.61 | 17.19 | 10 per cent decline |
Clinical trial details
The 40-week study used weekly subcutaneous injections of tirzepatide. The dose began at 2.5 mg and increased by 2.5 mg every four weeks until reaching a maintenance dose of 15 mg at week 20. The resistance training sessions were one hour long and supervised by accredited exercise physiologists.
Professor Green said the objective for people using these drugs should be improving overall health and function rather than focusing solely on the number on a scale.
This study shows that combining weight loss therapy and resistance exercise improves overall health,
Professor Green said.