Weight-loss injections like Ozempic, Wegovy, and Mounjaro are exceptionally popular – and with good reason – they can help people shed serious weight, often where nothing else has worked. But if you’re using (or considering using) one of these medications, it’s really important to understand that they don’t just help you lose fat – they can also lead to muscle loss.
The loss of lean muscle mass, especially as we age, has a variety of negative effects on health. Therefore, a healthy future should involve retaining as much muscle tissue as possible.
In this blog, we’ll take a detailed look at the issues surrounding weight loss medications and reduced muscle mass – as well as why strength training on Ozempic and similar medications can support your health. No scare tactics or sales pitches – just useful information about how to look and feel good, inside and out.
The Background: What Are GLP-1 Medications and How Do They Work?
GLP-1 agonists like Ozempic and Wegovy, along with dual agonists like Mounjaro, were originally developed to manage type 2 diabetes. But they’ve gained fame for another reason – they significantly reduce appetite, slow digestion, and improve blood sugar regulation.
The result? Substantial weight loss that, in some cases, rivals the results of bariatric surgery.
At Fitness Lab, we’ve worked with clients using these medications and understand how the body responds. Weight comes off – sometimes quickly – but without the right plan in place, so does valuable muscle.
To put a tangible number on this, trials have shown that people can lose 13.9% of muscle mass from their overall body composition when using these drugs. In context? Losing this amount of muscle through natural ageing would take roughly 20 years for most people.
The Hidden Cost of Weight Loss: Muscle Loss
Losing some muscle during weight loss is normal. But when that weight drops fast – as it often does with GLP-1 meds – muscle mass can vanish at this alarming rate.
And why does that matter? Well, less muscle means:
- Higher chances of regaining weight later
- Less strength and mobility
- Increased risk of fractures due to bone density loss
- Greater risk of accelerated sarcopenia (especially as we age)
What’s more, muscle burns more calories than fat – even when you’re watching Netflix. So in simple terms, losing muscle = slower metabolism.
Why Muscle Loss Happens on GLP-1 Meds
A big part of the problem is fairly obvious: less food = less fuel to maintain lean muscle mass. Add in the nausea or fatigue some people experience, and you’ve got a recipe for skipping meals – and skipping workouts.
Protein intake often drops as calorie intake reduces. Activity levels fall. And the scales don’t necessarily tell the full story. Even body scans like DEXA can be misleading – they track “lean mass,” which includes more than just muscle (think water, organs, etc.). So even if you’re being prudent – you might be losing muscle without even realising.
Who’s Most at Risk of Muscle Loss?
Some groups are more vulnerable than others:
- Older adults
- People who are inactive or sedentary
- Anyone with low muscle mass to start with
- Women (especially post-menopause)
- Those recovering from illness or injury
If you’re not actively working to maintain your muscle, you’re likely losing it – even if you’re feeling great and dropping pounds.
Why Strength Training Can Be Considered Non-Negotiable
Without a shadow of a doubt, resistance training is your best defence against the loss of muscle and its associated health impact.
Here’s exactly why quality resistance training matters:
- Preserves muscle mass: It sends a strong signal to your body to keep – or even build – muscle.
- Supports your metabolism: More muscle = more calories burned, even at rest.
- Improves bone health: Especially crucial if you’re losing weight fast.
- Enhances daily function: From carrying bags to climbing stairs, strength makes life easier.
- Lifts your mood and energy: Strength training releases endorphins and boosts motivation — the perfect antidote to low-energy days.
If you’re looking for a secret weapon that moves all of the needles in the right direction, you’ll find it in the gym – even if you can only manage a couple of sessions a week. That secret weapon becomes even more effective when you add a personal trainer to help you focus on getting strength training exactly right.
Nutrition to Support Muscle Retention
Now of course, adding resistance training is one thing – but a good personal trainer will explain that what you do in the gym can be boosted significantly if you think about maintaining muscle mass in the kitchen too.
When it comes to muscle – protein is essential. It’s a good idea to aim for at least 1.0–1.2g per kg of your target body weight. That might sound technical, but in practice it means prioritising protein at every meal. Lean meats, fish, Greek yoghurt, eggs, and legumes are your friends.
Supplements like whey protein, BCAAs, and essential amino acids can help preserve lean muscle mass too, especially if you’re struggling with nausea or appetite.
And don’t forget hydration – water and electrolytes matter more than you might think, particularly if you’re experiencing digestive side effects.
Why Strength Training With a Personal Trainer is Ideal on Weight Loss Meds
There’s no doubt about it, figuring all this out alone is tough, especially when you’ve got a busy life. That’s exactly why working with a trainer makes a difference:
- Safe progression: Especially key if you’re new or easing back in.
- Form & feedback: No injuries, no wasted time.
- Consistency: You’re more likely to stick to it when someone’s in your corner.
- Tailored to you: Every session adjusted to your energy, ability, and goals.
- Private and focused: Working one-to-one with a coach gives a distraction-free space to train confidently.
Of course, there are alternatives – be it entirely online training, app-based workouts, or even consulting your favourite AI tool to ask for some tips. While all of these things have their own merits, experience tells us that the support, accountability, and guideance you’ll get from a real-life coach just can’t be matched.
What Success Looks Like
With the right support, here’s what we almost always see:
- Increased strength and definition
- A healthier ratio of muscle to fat (even if the scale stays the same)
- More energy and a more stable mood
- Long-term weight maintenance without the rebound
Imagine two people that weigh the same – but one has more muscle and less fat. That’s the difference strength training makes.
Now, it’s important to be really clear that there’s a bit difference between training for toned muscle mass and training to become a bodybuilder. It’s a misconception that picking up weights will lead to a huge physique complete with rippling muscles. Strength training isn’t about this – it’s about a firmer, leaner body that’s more toned – and in better shape to keep you health as you age.
Final Thoughts
So, in a nutshell – Does Ozempic cause muscle loss? It can – but it doesn’t have to. Do you lose muscle on Wegovy? Without strength training and proper nutrition, there’s a good chance. Can you exercise on Ozempic? Absolutely – and you should. Can you build muscle on Ozempic? With the right training and support, yes.
There are lots of misunderstandings and unanswered questions out there about weight loss meds and muscle – which is another great reason to work with people who understand exactly what’s going on.
Ultimately, this isn’t just about weight loss – it’s about how you lose weight, and what kind of body you’re left with. Frankly, strength training should be considered essential rather than optional when these medications are dispensed – but it can be easy to get caught up in the initial excitement of the scales moving.
If you’re ready to protect your health, build strength, and keep your hard-earned progress, talk to a trainer who understands GLP-1 support – because you deserve more than a smaller number on the scale. You deserve a stronger, healthier body – for life.
