Strength Training on Ozempic, Wegovy or Mounjaro: Protecting Muscle

If your doctor has prescribed a GLP-1 medication such as Ozempic, Wegovy or Mounjaro, strength training is the most useful thing you can add. These drugs lower appetite and can produce large weight loss, and some of that loss is lean mass, as with any big weight change. Lifting two to three times a week and getting enough protein are the levers you control to keep more muscle, so the weight that comes off is mostly fat. Talk to your doctor before starting, and leave every question about the medication itself to them.

What the medications do, in brief

GLP-1 medications are prescription drugs, used for type 2 diabetes and, for some products, weight management. In the STEP 1 trial, adults with overweight or obesity who took weekly semaglutide 2.4 mg alongside lifestyle support lost an average of 14.9% of their body weight over 68 weeks, compared with 2.4% on placebo (Wilding et al., 2021). Nausea and diarrhea were the most common side effects.

Whether one of these medications is right for you, which one and at what dose is a decision for you and your doctor. This page assumes that decision is made and covers what you do in the gym and the kitchen.

One safety point: Health Canada warns that fake and unauthorized GLP-1 products are being sold online and in stores. Only buy prescription drugs from a licensed pharmacy, and check for the eight-digit Drug Identification Number (DIN) on the label (Health Canada).

The muscle question

When you lose a lot of weight quickly, some of it is lean mass. A 2024 review of GLP-1-based therapies found wide variation between trials: in some, lean mass made up 40 to 60% of the weight lost; in others, about 15% or less (Neeland et al., 2024). The authors note that lean mass includes organs, water and bone as well as muscle, and that newer imaging suggests the muscle changes may be roughly what you’d expect from the weight loss itself.

For a man over 40, the practical point is the same either way. You’ve already been losing muscle slowly with age, and you don’t want a rapid weight loss to speed that up. Strength matters for getting up stairs, carrying groceries and staying independent later, not just for looks. More on that in preventing muscle loss after 40.

There’s also evidence that combining exercise with a GLP-1 medication works better than either alone. In a one-year trial after an initial diet, people who combined exercise with liraglutide reduced their body-fat percentage about twice as much as those using exercise or the medication alone (Lundgren et al., 2021).

A strength plan that fits a GLP-1

Lower appetite and occasional nausea change how you should train. Keep it simple and consistent.

If you’ve never lifted, a structured beginner strength program over 40 is the easiest way in.

Eating when you’re not hungry

The challenge on a GLP-1 isn’t overeating; it’s getting enough protein when food doesn’t appeal.

• Lead with protein at every meal. Eat it first while appetite is highest.
• Use smaller, more frequent portions if large meals sit badly.
• Lean on easy protein: Greek yogurt, cottage cheese, eggs, milk, fish, chicken, a shake if solid food is hard.
• Drink enough fluid, especially on training days.

A meta-analysis of lifting studies found protein’s benefit for muscle levelled off around 1.6 g per kilogram of bodyweight a day (Morton et al., 2018). That’s a reasonable upper reference, but on a GLP-1 your doctor or a registered dietitian should set the target, especially if you have kidney disease or diabetes. The general guide is in how much protein a man over 40 needs.

Training around side effects

• Train on the days and at the times you feel best.
• If you feel nauseous, choose machines and lighter loads, skip intervals, and keep the session short.
• Stop and sit down if you feel dizzy or lightheaded, and tell your doctor if it happens more than once.
• Eat something small and easy before training if you’ve had little all day.

Planning for later

Many people regain weight after stopping these medications, which is covered in keeping weight off after stopping a GLP-1. The muscle and habits you build now are what you’ll rely on then.

The bottom line

On a GLP-1, the medication handles appetite; your job is to make sure the weight you lose is mostly fat. Lift two or three times a week, push protein within what your doctor recommends, walk daily and track strength alongside the scale. If you want a coach to run the training and nutrition side month to month while your doctor manages the medication, Monthly 1:1 Coaching covers a personalized strength program, a nutrition strategy and regular check-ins.