GLP-1s and Strength Training: What Your Doctor Isn't Telling You About Muscle Loss
If your doctor prescribed you a GLP-1 medication because you have a medical condition that warrants it (type 2 diabetes, significant obesity with health complications) then this article is for you. These drugs work for weight loss. That's not in question.
But here's what I need you to understand: if you're on one of these medications and you're not strength training, you're setting yourself up for a problem that goes beyond the number on the scale.
And if you're taking them without a medical need, just because you want to lose weight? Then we need to have a different conversation. Because when you come off these drugs (and most people do eventually), you could end up right back to where you started if you haven't built sustainable habits around training and nutrition. Except now on top of that, you've lost muscle mass that you didn't need to lose.
This isn't about GLP-1s being good or bad. It's about understanding what's actually happening to your body while you're on them, and making sure you're doing the work that ensures the weight you're losing is fat, not muscle.
The Problem: Not All Weight Loss Is Equal
When you lose weight rapidly without resistance training, you don't just lose fat. You lose muscle mass alongside it. And the research on GLP-1 medications shows this happening at rates that should make us pay attention.
Multiple studies have found that lean body mass (which includes your skeletal muscle) can account for anywhere from 15% to 40% of the total weight lost while on GLP-1 medications.[1] A 2025 meta-analysis of 22 randomized controlled trials involving over 2,200 participants found that lean mass typically makes up approximately 25% of overall weight loss.[2]
Let's put that in real numbers. If you lose 50 pounds on a GLP-1, you could be losing 12 to 20 pounds of that in lean tissue. For a desk worker in their 30s to 50s who's already losing muscle naturally due to aging, that's a BIG problem.
Why This Matters in the Long-Term
Muscle mass isn't just about aesthetics or strength. It's about how your body functions.
Metabolic health: Muscle tissue is metabolically active. It burns calories at rest, helps regulate blood sugar, and supports insulin sensitivity. Losing significant muscle mass can work against the metabolic improvements you're trying to achieve.
Bone density: Your muscles and bones work together. When you lose muscle mass rapidly, especially during significant weight loss, you may also be putting your bone density at risk. The research here is more complex, some studies show increased osteoporosis risk among GLP-1 users,[3][4] while others suggest neutral or even protective effects.[5] What's clear is that rapid weight loss itself is associated with bone loss, and the FDA has included warnings about fracture risk on some GLP-1 medications.[3]
Strength and function: This is where it hits home for most people. Muscle loss means reduced strength. It means everyday tasks (carrying groceries, playing with your kids, getting up from a chair) get harder. Studies tracking muscle strength in older adults on GLP-1s have shown concerning declines in grip strength and functional capacity, particularly after extended use.[6]
The goal isn't just to weigh less. It's to be strong, functional, and built to last well into your 60s, 70s, and beyond.
The Solution: Strength Training as Non-Negotiable
The good news is, this is preventable.
A 2024 study published in JAMA Network Open found something critical. When people combined GLP-1 medications with exercise, they achieved significant weight loss while preserving bone health. The participants who exercised didn't experience bone density loss, unlike those who took the medication without a structured exercise program.[7]
The research consensus is clear, targeted nutrition with optimized protein intake and frequent resistance training can minimize muscle loss while promoting fat loss during GLP-1 treatment.[1]
If you're on a GLP-1, strength training isn't optional. It's the insurance policy that ensures you're losing fat, not function.
What This Would Actually Look Like
You don't need a complicated program. You don't need to train five days a week or lift like a competitive athlete. What you need is consistent resistance training that covers the fundamental movement patterns your body was designed to perform.
The five essential movements:
- Squat pattern, builds leg strength, supports everyday movements like sitting and standing
- Hinge pattern, deadlifts and variations, protects your back and builds posterior chain strength
- Horizontal push, bench press, push-ups, builds chest and triceps
- Horizontal pull, rows, supports posture and back strength
- Vertical push/pull, overhead press and pull-ups/lat pulldowns, builds shoulder stability and upper body strength
Two to three sessions per week, 45 to 60 minutes each, focusing on progressive overload (gradually adding weight or reps over time) is enough to protect your muscle mass during weight loss.
Protein matters too. Most people on GLP-1s naturally eat less due to reduced appetite. That's the mechanism that drives weight loss. But if you're not intentionally getting adequate protein, you're making muscle loss worse. General adult recommendations are 1.2-1.6 g/kg/day, (So an 150 pound individual could need anywhere from 81 - 109 g of protein a day) but your level of physical activity and your exact goals would influence what that amount would be. An active individual would need more, especially if they were in a caloric deficit.
The RPE Approach: Training Smart on GLP-1s
Here's what I tell my clients who are on these medications, "we're not training for a powerlifting meet". We're training to preserve what you have and build sustainable strength.
For most of my adults, that means using an RPE (Rate of Perceived Exertion) approach rather than chasing maximal loads. You want to work hard enough to stimulate muscle growth and retention, typically in the RPE 6 to 8 range, meaning you could do 2 to 4 more reps if you had to, without running yourself into the ground.
Why is that? Because GLP-1s can affect your energy levels and recovery. You're in a caloric deficit. Your body is adapting to significant metabolic changes. Sustainability beats intensity here.
This is about building a practice that lasts, and avoiding burnout in six weeks.
If You're Already on a GLP-1
If you're currently taking one of these medications and you're not strength training, start now. Not next month. Now.
Talk to your doctor about adding resistance training to your routine. Most physicians worth their salt will not only support it, they'll encourage it. The medical community is increasingly aware of the muscle loss issue, and the recommendation is becoming standard practice.
If you don't know where to start, find a coach who understands appropriate programming, who can scale that intensity as needed, and who prioritizes long-term sustainability over quick results.
The Bigger Picture
GLP-1 medications represent a genuine breakthrough in treating obesity and metabolic disease. They're helping people who've struggled for years finally start to see some results. That can be worth celebrating.
But like any powerful tool, they work best when combined with the right supporting strategies, and when everything being done is intentional. Strength training isn't just something that's nice to do. It's the thing that ensures you're building a body that's not just lighter, but stronger, more functional, and built to last.
You don't want to just lose weight. You want to build a life where you're still active, independent, and capable at 60, 70, and 80 years old.
Strength training is how we get you get there.
Talk soon,
Christian Clarke, CSCS
References:
[1] Muaaz, Z., et al. (2025). Impact of GLP-1 Receptor Agonist Therapy in Patients High Risk for Sarcopenia. Current Nutrition Reports. https://pubmed.ncbi.nlm.nih.gov/40289060/
[2] Karakasis, P., et al. (2025). GLP-1 receptor agonists and sarcopenia: Weight loss at a cost? A brief narrative review. Diabetes Research and Clinical Practice. https://www.sciencedirect.com/science/article/abs/pii/S0168822725009386
[3] Horneff, J., et al. (2026). Research presented at American Academy of Orthopaedic Surgeons annual meeting. https://www.nbcnews.com/health/health-news/glp-1s-may-increase-risk-osteoporosis-gout-new-research-finds-rcna261024
[4] Medical News Today. (2026). GLP-1s may increase osteoporosis risk. https://www.medicalnewstoday.com/articles/glp-1s-osteoporosis-bone-health
[5] Use of GLP-1 receptor agonist and risk of osteoporosis among patients with type 2 diabetes: a real-world study. (2025). Frontiers in Endocrinology. https://www.frontiersin.org/journals/endocrinology/articles/10.3389/fendo.2025.1586589/full
[6] Prokopidis, K., et al. (2026). Glucagon-like peptide-1 receptor agonists and muscle strength changes in older adults: Risks beyond muscle mass reductions. British Journal of Pharmacology. https://bpspubs.onlinelibrary.wiley.com/doi/10.1111/bph.70355
[7] Iepsen, E.W., et al. (2024). Bone Health After Exercise Alone, GLP-1 Receptor Agonist Treatment, or Combination Treatment: A Secondary Analysis of a Randomized Clinical Trial. JAMA Network Open. https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2820308
This is exactly why I built The Second Rep, sustainable strength programs for desk workers and busy professionals who want to train smart, not just hard. If you're looking for programming that fits your life and builds strength that lasts, check out thesecondrep.com/start.
Member discussion