GLP‑1 medications like Ozempic, Mounjaro , Wegovy, Trulicity, Saxenda have become very popular for their successful weight loss results which offer real benefits.
Many users experience improved confidence, reduced joint pain, better blood sugar control, and overall health gains.
For those with obesity-related conditions, the impact can be life-changing.
At the same time, a known risk factor is the reduction of lean muscle mass during weight loss on GLP‑1 medications.
Without strength training and proper nutrition, the weight lost may include valuable lean tissue that can reduce your metabolic rate, increase risk of injury, and make future weight maintenance more difficult.
In fact, research shows that up to 25–39% of total weight lost can be muscle not fat. To put that in perspective, if someone loses 20 kilograms, up to 8 kilograms of that could be from lean tissue.
Why does this matter?
Muscle is not just for strength, it fuels your metabolism, supports daily function, balance, mobility and protects against injury.
Losing muscle can lead to a slower metabolic rate, which makes it harder to maintain healthy weight long-term and increases the risk of weight regain once you stop the medication.
In this article, we will explore why strength training and professional support are essential to preserve muscle, metabolism, and lasting results while using GLP‑1 medications.
What is Happening to Your Muscles with GLP‑1’s?
GLP‑1 works by suppressing appetite and slowing digestion, leading to rapid weight loss.
But a significant risk is that up to 25–39% of total weight lost may come from lean muscle, not just fat.
This represents a significant physiological shift, not just a change in appearance, but a reduction in the very tissue that supports your metabolism and functional health.
Muscle is metabolically active tissue.
Losing it slows down your resting metabolic rate, which makes it harder to maintain a healthy weight over time.
This reduction in metabolism can lead to weight regain when you stop taking the medication.
Strength work is key to protecting your metabolic engine, allowing you to sustain results even beyond the medication.
Interesting fact – Building new muscle takes months or even years, while losing it can happen in just a matter of weeks, a disparity that can significantly impact your long-term outcomes, if not addressed through targeted strength training and proper nutrition.
Evidence-Based Tips to Protect Muscle While Using GLP‑1s
1.Eat Enough Protein – Aim for 0.8–1.2 grams per kilogram of body weight daily. Protein helps preserve muscle during calorie deficits.
2,Lift Weights 2–3x Per Week – Include compound movements like squats, deadlifts, rows, and presses.
3.Prioritise Recovery – Sleep and rest are essential for muscle repair, especially when your body is adapting to medication.
4.Hydrate and Supplement Wisely – Appetite loss can lead to nutrient gaps. Stay hydrated and consider supplements particularly if deficiencies are identified.
5.Track Progress & Adjust – Regularly assess lean muscle mass, strength, energy, and weight, and work with your personal trainer to make adjustments based on measuring tools like a bioimpedance meter.
Why You Should See a Personal Trainer for Strength Training
Strength training is the best strategy to preserve muscle while on GLP‑1 but how you do it, matters. A qualified personal trainer can:
-Select the best exercises to maximise muscle maintenance or gain based on your individual capacity and goals
-Track your progress, especially measuring lean muscle mass regularly to ensure you are maintaining and improving your body composition.
-Personalise your plan to match your energy levels, medical needs, goals, and postural considerations.
-Help maintain proper form to avoid injury, especially when motivation is low.
-Ensure progressive overload to keep muscle stimulated even with a reduced appetite.
-Adapt workouts to manage GI discomfort or fatigue common on GLP‑1’s.
Most importantly, personal trainers keep you consistent something even the best program cannot do alone.
Simple Steps to Take Right Now
1.Book a session with a personal trainer—ideally one experienced with medical weight loss
2.Increase protein intake, even if in small, frequent doses
3.Start with two resistance sessions weekly, adding more as tolerated
4.Track how you feel—fatigue, energy, motivation and adjust accordingly
Summary
GLP‑1 medications can be a powerful tool for weight loss, but without strength training, the cost may be your muscle, metabolism, and momentum.
By pairing your medication with expert-led resistance/weight training and a nutrition plan that supports muscle maintenance, you can protect your strength and make your results sustainable for life.
Cameron Corish has been caring and achieving results for the local Wishart, Mansfield and Mt Gravatt community for over 15 years. He takes a multi-disciplined and holistic approach to health and fitness addressing the physical, mental and emotional aspects of one’s health.
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Research References
- Prado et al. (2024): 25–39% of weight loss may be lean mass. PubMed
- American Journal of Clinical Nutrition: Lean mass loss with rapid weight loss. PubMed
- MHRA UK (2024): Side effects overview. gov.uk
- Washington Post (2025): Strength and protein key to sustainable GLP‑1 success. washingtonpost.com
