Taking Mounjaro or Wegovy? You may have been told to prioritise resistance training while you're on a GLP-1 medicine. It's sound advice.
If your muscles aren't getting enough of a challenge, you can end up losing more muscle relative to fat.
The good news is that you don't need years of gym experience to protect your muscle. This guide covers how much resistance training the evidence supports, which type suits beginners, how to structure your first few weeks, and how to work around common side effects like nausea and tiredness.
Two short sessions a week is enough to start protecting your muscle. No gym experience needed.
Why resistance training matters on GLP-1 medications
Mounjaro (tirzepatide) and Wegovy (semaglutide) mimic gut hormones that tell your brain you're full. They also slow how quickly your stomach empties, which is why your appetite and portion sizes drop so noticeably in the first few months.
Eating less creates a calorie deficit. And in any calorie deficit, your body draws energy from both fat and muscle, unless it's given a reason to hold on to the muscle.
A body scan (DXA) substudy of the SURMOUNT-1 trial found that around 75% of the weight lost on tirzepatide came from fat, with roughly 25% from lean mass.1 That's broadly similar to weight lost through diet alone, so the medicine itself doesn't seem to tip the balance towards losing more muscle.
That's reassuring. But resistance training is widely recommended as the best way to shift that balance further towards fat loss, because it gives your muscles a reason to adapt rather than shrink.
Holding on to as much muscle as you can has longer-term benefits too. Muscle helps keep your resting metabolic rate up, which is the energy your body burns at rest, and that may make your results easier to maintain. We cover this in more detail in our article on whether Mounjaro or Wegovy causes muscle loss.
How much resistance training do you actually need?
The UK Chief Medical Officers' physical activity guidelines say adults should do activities that work all the major muscle groups on at least 2 days a week. That means your legs, hips, back, abdomen, chest, shoulders and arms.2
The NHS gives the same 2-day target for muscle-strengthening activity. That's alongside a separate goal of at least 150 minutes of moderate activity a week, such as brisk walking, spread across 4 to 5 days.3
If you're just starting out on Mounjaro or Wegovy, the strengthening target is the one that matters most for protecting muscle. And it's genuinely achievable. Two sessions a week is enough, even if you've never lifted a weight before, and each one doesn't need to last more than 30 to 45 minutes.
Pick two days you can stick to, like Monday and Thursday, and treat them like any other appointment.
Which type of resistance training should you choose?
There's no single correct way to strength train. The best choice is whichever one you'll actually stick with.
Bodyweight exercises
Squats, push-ups (including wall or knee versions), lunges and glute bridges need no equipment and can be done at home. They're the natural starting point if you're new to resistance training, because they let you learn the movement before adding weight.
Resistance bands
Bands are cheap, portable and easy to adjust, just by changing the band or your grip. They're a good bridge between bodyweight training and free weights, especially for upper body and shoulder work.
Free weights
Dumbbells and kettlebells let you progress more precisely than bands, since you can increase the weight in small, specific steps. New to free weights? Start light and focus on controlled movement rather than lifting as much as you can.
Gym machines
Machines guide the movement for you, which can feel more confidence-inspiring if you're unsteady with free weights. Most gyms offer a free induction, which is worth taking if you've never used resistance machines before.
Getting started as a complete beginner
Start with bodyweight movements before adding any extra load. That way, you can learn how to squat, push and hinge without worrying about how much you're lifting.
A simple beginner structure might look like this:
- Weeks 1 to 2 - bodyweight squats, wall or knee push-ups and glute bridges, at 2 sets of 8 to 12 reps
- Weeks 3 to 4 - add a resistance band or a light pair of dumbbells to the same moves, still at 2 to 3 sets
- Week 5 onwards - increase the weight gradually once you can complete all your sets and reps with good form. This is known as progressive overload.
Do not push through a set once your form breaks down. Stop, rest, and lower the weight if you need to.
Rest for at least 48 hours between sessions that work the same muscles. And don't be discouraged if strength gains feel slow in the first month. Your body is adapting to a new type of exercise and a new medicine at the same time, so consistency matters far more than intensity early on.
A 5-minute warm-up of light movement, such as marching on the spot or gentle arm circles, helps prepare your joints. It also lowers the chance of straining a muscle before it's used to load.
Move through the full range of each exercise with control, rather than rushing. Stop a set if your form starts to slip, rather than pushing on to a fixed number. A rep done with poor technique won't build strength any faster, and it raises your risk of injury.
Pair your training with enough protein. It gives your muscles the raw materials they need to respond, so think about both together rather than exercise alone.
How does resistance training fit alongside cardio?
Resistance training and aerobic activity, like walking, cycling or swimming, do different jobs. Aerobic exercise burns calories during the activity and supports your heart and lungs. Resistance training is what tells your body that muscle is worth keeping, even as you lose weight.
Neither replaces the other. The NHS guidance covers both because they work best together.3
New to exercise altogether? It's reasonable to introduce them gradually, rather than trying to meet both targets in your first week. Many people find it easier to build a walking habit first, since it needs no equipment or technique, then add 2 resistance sessions once that feels manageable.
There's no strict order to follow. What matters is getting both in place early in treatment, when weight loss is often at its fastest.
Managing training around side effects
The most commonly reported side effects of GLP-1 medicines are digestive, and they can make a session feel harder than it should:
- Nausea - very common, especially in the first few weeks after a dose increase. Training earlier in the day, before symptoms build, and keeping sessions shorter until it settles can help.4
- Tiredness - very common with Wegovy and common with Mounjaro, especially around dose increases. Lower the intensity rather than skipping the session altogether where you can.4
- Low appetite before training - if training on an empty stomach leaves you light-headed, a small, easily digested snack such as a banana or plain toast 30 to 60 minutes beforehand can help.
- Dehydration - drinking less, plus digestive side effects, can affect your performance and recovery. Sip water throughout your session rather than drinking a lot at once.
- Injection site soreness - if you inject into your thigh or tummy, a session that heavily works that area on the same day can feel uncomfortable. Either train a different muscle group that day, or rotate your injection site away from the area you plan to train.
Feeling dizzy or faint during a session? Stop straight away, sit down and have some water before you try to carry on.
Nausea or tiredness bad enough to stop you training altogether? Raise it with your prescriber. It may mean your dose needs more time to settle, or your titration is moving faster than your body can keep up with.
When should you seek medical advice?
Speak to your prescriber or GP if:
- You feel persistently weak or unusually breathless during light activity
- You experience dizziness or fainting during or after exercise
- Nausea, vomiting or diarrhoea are severe enough to affect your ability to eat or drink normally
- You notice a rapid or unexplained drop in strength alongside your weight loss
Frequently asked questions
How many days a week should you do resistance training on Mounjaro or Wegovy?
NHS general guidance recommends muscle-strengthening activity at least 2 days a week for all adults. A 2025 clinical advisory on GLP-1 nutrition support suggests building towards 3 sessions a week specifically to help protect muscle during rapid weight loss. Starting with 2 sessions and adding a third once that feels manageable is a sensible approach.
Can beginners do resistance training without a gym?
Yes. Bodyweight exercises such as squats, push-ups, and planks, combined with resistance bands, can build meaningful strength without any gym equipment. A gym or free weights become more useful once bodyweight exercises start to feel too easy.
Is it safe to start resistance training if you feel nauseous on Mounjaro or Wegovy?
Light to moderate activity is usually fine, but it's sensible to lower intensity or shorten sessions in the days following a dose increase, when nausea and fatigue tend to be strongest. If symptoms are severe or last more than a week or two, speak to your prescriber.
How long before you see results from resistance training on GLP-1 medication?
Early strength gains often come from improved coordination and nervous system adaptation rather than visible muscle change, so noticeable results can take several weeks to a few months. Consistency matters more than the intensity of any single session.
Do you need to lift heavy weights to protect muscle on Wegovy or Mounjaro?
No. Bodyweight and light to moderate resistance, done consistently and taken close to muscular fatigue, is enough to signal to your body that muscle is still needed. Heavier lifting can help once you've built a foundation, but it isn't a requirement for beginners.
What happens if you only do cardio and skip resistance training on GLP-1 medication?
You'll likely still lose weight, since Mounjaro and Wegovy work mainly by reducing appetite. Without resistance training, though, a larger share of that weight loss is likely to come from muscle rather than fat.
References
- Look M, et al. Body composition changes during weight reduction with tirzepatide in the SURMOUNT-1 study of adults with obesity or overweight. Diabetes, Obesity and Metabolism. 2025. dom-pubs.onlinelibrary.wiley.com
- UK Chief Medical Officers. Physical activity guidelines. GOV.UK; 2019. gov.uk
- NHS. Physical activity guidelines for adults aged 19 to 64. NHS; 2021. nhs.uk
- Electronic Medicines Compendium. Mounjaro SmPC; Wegovy SmPC. eMC. medicines.org.uk/emc
This article is intended for informational purposes only and does not replace professional medical advice. Always read the patient information leaflet supplied with your medication and speak to a healthcare professional if you have specific concerns.