- Strength training matters because part of the weight lost on a GLP-1 is lean mass: about 25% on tirzepatide in SURMOUNT-1 scans. A 2025 advisory recommends strength training at least three times a week plus at least 150 minutes of moderate aerobic exercise.3,4
- In a 1-year trial, exercise plus liraglutide kept off 9.5 kg more than placebo, and cut body fat about twice as much as either alone.1
- A year after treatment stopped, people who had exercised held on to more of their weight loss.2
Why strength training matters on a GLP-1
When you lose weight, some of it is lean mass: muscle, plus water, organs and bone. GLP-1 medicines are no exception. In a body-scan substudy of 160 adults in SURMOUNT-1, tirzepatide (Zepbound, Mounjaro) reduced fat mass by 33.9% and lean mass by 10.9%. About 75% of the weight lost was fat and 25% lean, the same split as on placebo.4 In STEP 1 scans, about 38% of the weight lost on semaglutide (Wegovy) was lean mass, as summarized in the 2025 advisory.3
We cover those scans, and how much protein the research suggests, in how much protein you need on a GLP-1. The short point here: the advisory says lean mass loss depends partly on whether people do strength training, and that "increased protein intake alone is likely inadequate" without it.3
What the research says about exercise plus a GLP-1
The best randomized evidence comes from a Copenhagen trial published in the New England Journal of Medicine in 2021. It tested liraglutide (Saxenda), an older daily GLP-1, not semaglutide or tirzepatide.1
195 adults with obesity (BMI 32 to 43) and no diabetes first lost an average of 13.1 kg on an 8-week low-calorie diet. They were then randomly assigned for one year to a moderate-to-vigorous exercise program, liraglutide 3.0 mg a day, both, or placebo.1
- All three active strategies beat placebo for weight, with the combination doing best (9.5 kg more than placebo).1
- The combination cut body-fat percentage by 3.9 points, about twice as much as exercise alone (1.7) or liraglutide alone (1.9).1
- Only the combination improved HbA1c, insulin sensitivity and cardiorespiratory fitness.1
The 2025 advisory adds that in a recent randomized trial, a year of GLP-1 therapy with exercise preserved bone density, while the GLP-1 alone reduced it.3
What happened after treatment stopped
The same team checked 109 participants one year after all treatment ended.2
People who had done exercise plus liraglutide were also more likely to still be at least 10% below their starting weight than those who had taken placebo (odds ratio 7.2).2 This is a small trial and the post-treatment phase lost some participants, so treat it as encouraging, not settled. For more on what happens after stopping, see stopping a GLP-1 and weight regain.
How much exercise do guidelines recommend on a GLP-1?
| Source | Aerobic activity | Strength training |
|---|---|---|
| Physical Activity Guidelines for Americans (all adults) | 150–300 min a week moderate, or 75–150 min vigorous, or a mix | 2 or more days a week |
| 2025 GLP-1 joint advisory (adults on GLP-1s for obesity) | At least 150 min a week moderate | At least 3 times a week |
The US guidelines add that older adults should include balance training, that adults with chronic conditions should follow the same targets if they are able, and that people doing the least activity gain the most from even modest increases.5 The advisory says plans should be fitted to each person's fitness level, and that strength or mixed training preserves lean mass better than aerobic exercise alone.3
What a guideline-sized week can look like
This is an illustration of the amounts above, not a prescription. Check with your clinician before starting, especially if you have heart, joint or other health conditions.
| Day | Example |
|---|---|
| Monday | Strength, about 30 min: squats or sit-to-stand, push-ups against a wall or bench, rows with a band, glute bridges |
| Tuesday | Brisk walk, 30 min |
| Wednesday | Strength, about 30 min |
| Thursday | Brisk walk or cycling, 30 min |
| Friday | Strength, about 30 min |
| Saturday | Longer walk, swim or bike, 60 min |
| Sunday | Easy walk, 30 min, or stretching |
Bodyweight moves, resistance bands and gym machines all count as strength work. Many people start below these amounts and build up.
Exercising with nausea and low appetite
Stomach side effects are common early on. In the SURMOUNT-1 and SURMOUNT-2 trials, gastrointestinal side effects affected 56% of people on tirzepatide vs 30% on placebo. The Zepbound label says most nausea, vomiting and diarrhea happened during dose increases and eased over time.6
- Fluids. The Wegovy label warns that dehydration from vomiting or diarrhea has led to kidney injury, and that patients should take precautions to avoid fluid loss.6 Sweating adds to that.
- Low blood sugar. The labels warn that using these medicines with insulin or a sulfonylurea raises the risk of hypoglycemia.6 If you take those, ask your care team how to plan exercise.
- Fuel. Smaller meals can leave little energy for training. See what to eat on a GLP-1.
Common questions
Should you do strength training on a GLP-1?
A 2025 joint advisory from four US nutrition and obesity societies says GLP-1 medicines for obesity should be paired with a structured exercise program, including strength training at least three times a week. It says higher protein alone is likely not enough to preserve muscle without strength training.
What is a good GLP-1 exercise plan?
The Physical Activity Guidelines for Americans recommend 150 to 300 minutes a week of moderate aerobic activity, or 75 to 150 minutes of vigorous activity, plus muscle-strengthening on 2 or more days. The 2025 GLP-1 advisory aims a little higher on strength: at least three sessions a week plus at least 150 minutes of moderate aerobic exercise.
How much muscle do you lose on a GLP-1?
In the SURMOUNT-1 body-scan substudy of 160 adults with obesity or overweight, about 25% of the weight lost on tirzepatide was lean mass, the same share as on placebo. In STEP 1 scans, about 38% of the weight lost on semaglutide was lean mass.
Does exercise help keep weight off after stopping a GLP-1?
In a Danish trial of adults with obesity, people who stopped liraglutide alone regained 6.0 kg more in the following year than people who stopped a supervised exercise program. One year after treatment ended, those who had done exercise plus liraglutide weighed 5.1 kg less than those who had taken liraglutide alone.
Can you exercise with nausea on a GLP-1?
Stomach side effects are common: in the SURMOUNT-1 and SURMOUNT-2 trials, 56% of people on tirzepatide had gastrointestinal side effects vs 30% on placebo, mostly during dose increases. The Wegovy label warns that dehydration from vomiting or diarrhea can harm the kidneys, so ask your care team how to adjust exercise on bad days.
Sources
- Lundgren JR, Janus C, Jensen SBK, et al. Healthy Weight Loss Maintenance with Exercise, Liraglutide, or Both Combined. N Engl J Med. 2021;384(18):1719-1730. doi:10.1056/NEJMoa2028198 · PubMed
- Jensen SBK, Blond MB, Sandsdal RM, et al. Healthy weight loss maintenance with exercise, GLP-1 receptor agonist, or both combined followed by one year without treatment: a post-treatment analysis of a randomised placebo-controlled trial. EClinicalMedicine. 2024;69:102475. doi:10.1016/j.eclinm.2024.102475 · Full text (PMC)
- Mozaffarian D, Agarwal M, Aggarwal M, et al. Nutritional priorities to support GLP-1 therapy for obesity: A joint Advisory from the American College of Lifestyle Medicine, the American Society for Nutrition, the Obesity Medicine Association, and The Obesity Society. Obesity (Silver Spring). 2025;33(8):1475-1503. doi:10.1002/oby.24336 · Full text (PMC)
- Look M, Dunn JP, Kushner RF, et al. Body composition changes during weight reduction with tirzepatide in the SURMOUNT-1 study of adults with obesity or overweight. Diabetes Obes Metab. 2025;27(5):2720-2729. doi:10.1111/dom.16275 · Full text (PMC)
- Piercy KL, Troiano RP, Ballard RM, et al. The Physical Activity Guidelines for Americans. JAMA. 2018;320(19):2020-2028. doi:10.1001/jama.2018.14854 · Full text (PMC) · US guidelines
- US prescribing information: WEGOVY (sections 5.4, 5.5, 17; revised 06/2026) and ZEPBOUND (sections 5.7, 6.1; revised 08/2026). DailyMed, checked November 2026.
