GLP-1 Medications and Fitness: What You Need to Know (and Why Strength Training Matters)

GLP-1 medications — Ozempic, Wegovy, Mounjaro, and their generics — have changed how the world approaches weight loss. In Singapore, prescriptions are rising fast. And the results on the scale are real.

But there's a side effect most people aren't warned about: you're losing muscle, not just fat.         

This isn't a reason to avoid GLP-1s. It's a reason to pair them with the one thing that protects you — structured strength training.

What GLP-1 Medications Actually Do to Your Body

  GLP-1 (glucagon-like peptide-1) receptor agonists work by:

•   Suppressing appetite and increasing feelings of fullness                                             

• Slowing digestion so you feel satisfied longer                                                       

• Regulating blood sugar and insulin response   

Originally developed for type 2 diabetes, drugs like semaglutide (Ozempic/Wegovy) and tirzepatide (Mounjaro) are now widely prescribed for weight loss — and the WHO formally recognises them as valid obesity treatments.

The weight loss is real. Clinical trials show average losses of 10–15% of body weight over 68 weeks on semaglutide. Some people lose significantly more.

The problem is what kind of weight is being lost. 

The Muscle Loss Problem Nobody Talks About

Studies show that 25–40% of weight lost on GLP-1 medications can come from lean muscle mass — not fat.

This happens because:                                                                                  

• Appetite suppression means lower overall calorie and protein intake

• People naturally move less as they lose weight

• Without a resistance training signal, the body has no reason to hold onto muscle                     

  Why does this matter?                                                                                  

  Muscle is your metabolic engine. Lose too much of it and you end up with:                              

• A slower metabolism that makes weight regain more likely when you stop the medication

• Reduced strength and functional capacity                                                             

• Greater injury risk, especially as you age

• Lower bone density over time                                                                         

This is sometimes called the "Ozempic body" problem: people who are lighter on the scale but metabolically weaker than before. 

What the WHO Actually Says

The World Health Organization doesn't recommend GLP-1 medications in isolation. Their guidelines explicitly state these drugs should be used "in combination with lifestyle interventions", specifically:   

• Balanced nutrition with adequate protein

• Regular physical activity

• At minimum two days of strength training per week

• 150–300 minutes of moderate exercise, or 75–150 minutes of vigorous activity, weekly                 

Medication gets you to the starting line. What you do in the gym determines what your body looks like — and functions like — when you get there.

What This Looks Like in Practice

If you're on Ozempic, Wegovy, or any GLP-1 medication, here's what an effective training approach includes:                                                                                              

• Frequency: 2–3 strength sessions per week minimum                                                      

• Focus: Compound movements — squats, deadlifts, pressing, pulling — that recruit the most muscle

• Protein: Aim for 1.6–2.2g per kg of bodyweight daily to offset appetite suppression

• Intensity: Keep training challenging — appetite suppression can reduce perceived effort, but the muscle stimulus still needs to be there                                                                      

• Recovery: Prioritise sleep and manage stress, both of which affect muscle retention

Training on GLP-1 in Singapore: What to Expect

Lower appetite can affect energy levels, especially in the first 4–8 weeks of GLP-1 use. This is normal. It's also exactly when most people quietly reduce their training intensity or stop altogether — which accelerates the muscle loss problem.

This is where working with a coach matters. At Rx Performance, we train people through every phase of their health journey — including those using GLP-1 medications who want to make sure the weight they lose is fat, not muscle.

Frequently Asked Questions

Can I exercise while taking Ozempic or Wegovy?

Yes — and you should. Exercise, particularly strength training, is what makes GLP-1 medications work better long-term by preserving the muscle that drives your metabolism.                                 

Will I have enough energy to train on a GLP-1 medication?                                              

Energy can dip early in treatment. Starting with 2 sessions per week and progressively building is a smart approach. Most people find their energy stabilises after the first few weeks.                               

What type of exercise is best on GLP-1?                                                                

Strength training (resistance training) is the priority. It's the most effective way to prevent muscle loss. Cardio is beneficial too, but should not replace resistance work.                                

How much protein should I eat on Ozempic?                                                              

Because GLP-1 medications reduce appetite, hitting protein targets becomes harder. Aim for 1.6–2.2g of protein per kg of bodyweight daily. Protein shakes can help bridge the gap when appetite is low.       

Is GLP-1 medication available in Singapore?                                                            

Yes. Ozempic and Wegovy are available in Singapore through prescription. Costs will vary. Consult your GP or an endocrinologist.         

The Bottom Line                                                                       

GLP-1 medications are a legitimate, powerful tool. But they work best as part of a bigger picture — one that includes structured training, adequate nutrition, and long-term consistency.               

The goal isn't just a lower number on the scale. It's a stronger, healthier body that stays that way.  

Ready to train smarter alongside your GLP-1 journey?                                                   

Get started with our Personal Training starter pack.