Over the last 2 years of meeting with new personal training clients from all over Southern New Hampshire, we’ve seen a huge uptick in people who are taking weight loss drugs.
And we think it’s great! It makes us happy to hear that people are finding a great solution that is impacting their life in such a positive way. That being said, we’re finding that these same clients are seeking out personal training services to help preserve muscle mass while they undergo their weight loss journey.
GLP-1 medications like Ozempic, Wegovy, Mounjaro, and Zepbound have been game changers for so many of our clients; however, when weight comes off quickly, some of it can be muscle, and muscle is what keeps your metabolism, blood sugar, and strength working well. Strength training on a GLP-1 is one of the best ways to make sure the weight you lose is the weight you want to lose. Here’s what the research shows, and why it can be super beneficial to partner with a personal trainer for your weight loss journey.
1. Fast weight loss isn’t all fat
In the clinical trials behind these drugs, a meaningful share of the weight lost was lean mass. In the STEP 1 trial of semaglutide, body scans of a subgroup of participants showed that lean mass made up roughly 40% of the weight lost. In the SURMOUNT-1 trial of tirzepatide, it was closer to 25%. In both cases, people lost fat faster than lean mass, so their body composition improved overall. Still, losing muscle while losing weight has consequences for strength, function, and long-term health. One caveat: the “lean mass” measured on a DEXA scan includes more than muscle, such as organs and water, so not all of it is muscle tissue. The good news is that this is the part of weight loss you can influence. Resistance training signals your body to hold on to muscle, even while you’re eating less.
2. Muscle is your body’s main tool for managing blood sugar
Skeletal muscle is the largest organ in the body by mass, and it’s responsible for about 80% of the glucose your body takes up from the bloodstream after a meal. When insulin tells your body to clear sugar from your blood, most of it goes into muscle. It follows that holding on to muscle during weight loss is not just about appearance. It protects one of your body’s most important systems for keeping blood sugar steady. GLP-1 medications help with blood sugar, and strength training supports that same system from a different angle.
3. Muscle keeps your metabolism working
Your body’s daily energy use scales with how much fat-free mass you carry, which is mostly muscle, organs, and bone. A landmark study of more than 6,400 people found that once you account for fat-free mass, daily energy expenditure stays remarkably stable from age 20 to about 60. That means losing muscle lowers how much energy your body burns each day, while keeping it helps protect your metabolism. Researchers have also argued that losing fat-free mass, especially skeletal muscle, can have negative metabolic consequences, including weight regain. This is why the goal isn’t just a lower weight. It’s a better balance of muscle to fat. If you’re also navigating perimenopause or menopause, we dig into this more in our article on strength training for menopause.
4. What happens when you stop, and how exercise can help
Many people hope to eventually come off these medications, and it’s important to know what the research says. In the STEP 1 extension, participants who stopped semaglutide regained about two-thirds of the weight they’d lost within a year, and improvements in markers like blood pressure and blood sugar moved back toward their starting points. That’s why a plan for after the medication matters. A Danish trial offers a hopeful signal. Adults who lost weight and then followed a supervised exercise program, alone or alongside a GLP-1 drug, kept more of their weight loss and body composition improvements a year after treatment ended, compared with people who took the drug alone. Weight regain in the year after stopping was about 6 kilograms larger after stopping the drug alone than after stopping supervised exercise. To be fair, this was a single, relatively small trial of an older GLP-1 drug (liraglutide) over one year, and the exercise program was a supervised moderate-to-vigorous program, not strength training specifically. It doesn’t prove that exercise guarantees you can stay off medication. But it does suggest that building a supervised exercise habit while you’re on the drug is one of the best ways to prepare for life after it, and whether and when to stop is a decision for you and your prescriber.
5. Why a personal trainer makes a difference on a GLP-1
Training well while eating less takes some skill. Appetite is lower, energy can dip, and some people deal with nausea or fatigue, especially as doses change. A personal trainer can adjust your sessions to how you feel, keep the weights challenging enough to signal your body to hold on to muscle, and progress them over time. They can also track your strength and measurements, not just the scale, so you can see whether you’re keeping the muscle you want. And because everyone starts from a different place, individualized programming matters more than a generic routine. A good trainer will also coordinate with your doctor or dietitian, since nutrition and medication decisions belong with them.
Disclaimer: This article is for educational purposes only and is not medical advice. If you are taking a GLP-1 medication or have any medical condition, talk with your prescriber before starting a new exercise program, and do not change or stop your medication without their guidance.
Common questions about strength training on GLP-1 medication
Do GLP-1 medications cause muscle loss?
In clinical trials, roughly 25% to 40% of the weight lost on tirzepatide and semaglutide was lean mass, though lean mass on a DEXA scan includes more than muscle. People generally lost fat faster than lean mass, so body composition improved overall. Strength training and good nutrition are the main ways to protect muscle.
Should I do strength training while taking Ozempic, Wegovy, Mounjaro, or Zepbound?
It’s widely recommended, and research on exercise combined with a GLP-1 drug found better weight-loss maintenance and body-fat reductions than the drug alone. Check with your prescriber first, and start with a trainer who can adjust to how you feel.
Can strength training help me keep the weight off after I stop a GLP-1?
It may help. In one trial, people who had followed a supervised exercise program regained less weight after treatment ended than people who had taken the drug alone. It isn’t a guarantee, and most people regain some weight after stopping, so plan with your prescriber.
How much protein do I need on a GLP-1?
Protein needs vary by person, weight, and health, so ask your prescriber or a registered dietitian rather than relying on a generic number.
Do I really need a personal trainer WHILE on A GLP-1?
You can start on your own, but a trainer helps you pick the right exercises, progress safely, and adjust when appetite or energy changes. That support is especially useful if you’re new to lifting.
Personal training for weight loss in Epping, Raymond, Greenland, Rye, Portsmouth, and Lee, NH
If you’re looking for personal training for weight loss and GLP-1 support near you, we work with clients throughout southern New Hampshire, including Epping, Raymond, Greenland, Rye, Portsmouth, and Lee. Our personal training gyms are located at 1 Bayside Rd Ste 104, Greenland, NH 03840 and 285 Calef Hwy Unit 9, Epping, NH 03042 and serve almost 300 clients weekly. We’ll build a strength program around your medication schedule, your energy, and your goals.
Ready to protect your muscle and your results? Let’s get started.
The weight you lose is only part of the story. What you keep matters just as much: your strength, your metabolism, and your health. Here’s how to start:
Book a consultation. We’ll talk about where you are in your journey, what’s working, what isn’t, and what you want to feel like again. https://www.limitlessfitnessllc.com/get-started or call Greenland at (603) 334-5362 and Epping at (603) 734-2190
Get a program built for you. We’ll build strength training around your medication schedule, appetite, and energy, so you’re protecting muscle without overdoing it on low-fuel days.
Train with support. A trainer keeps you safe, tracks your progress, and raises the difficulty as you improve.
Sources
Wilding JPH et al., “Once-Weekly Semaglutide in Adults with Overweight or Obesity” (STEP 1), New England Journal of Medicine, 2021, including its DEXA substudy of 140 participants. https://doi.org/10.1056/NEJMoa2032183
Jastreboff AM et al., “Tirzepatide Once Weekly for the Treatment of Obesity” (SURMOUNT-1), New England Journal of Medicine, 2022, and its DEXA substudy, 2025. https://doi.org/10.1056/NEJMoa2206038
Merz KE, Thurmond DC, “Role of Skeletal Muscle in Insulin Resistance and Glucose Uptake,” Comprehensive Physiology, 2020. https://pmc.ncbi.nlm.nih.gov/articles/PMC8074531
Pontzer H et al., “Daily energy expenditure through the human life course,” Science, 2021. https://doi.org/10.1126/science.abe5017
D’Souza AC, Lau KJ, Phillips SM, “Exercise in the maintenance of weight loss: health benefits beyond lost weight on the scale,” British Journal of Sports Medicine, 2022. https://bjsm.bmj.com/content/56/13/771
Wilding JPH et al., “Weight regain and cardiometabolic effects after withdrawal of semaglutide: The STEP 1 trial extension,” Diabetes, Obesity and Metabolism, 2022.
Jensen SBK 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. https://doi.org/10.1016/j.eclinm.2024.102475
Lundgren JR et al., “Healthy Weight Loss Maintenance with Exercise, Liraglutide, or Both Combined,” New England Journal of Medicine, 2021. https://pubmed.ncbi.nlm.nih.gov/33951361