How do I prevent muscle loss on a GLP-1 like Ozempic, Wegovy or Zepbound?

How much muscle do people lose on GLP-1s?

Any fast weight loss, whether from GLP-1 medication, surgery, or a very low-calorie diet, usually takes some muscle along with the fat. The 2025 joint advisory from the American College of Lifestyle Medicine, the American Society for Nutrition, the Obesity Medicine Association, and The Obesity Society summarizes the data:^[1]

• In the STEP 1 semaglutide trial, participants lost an average of 13.6 kg (about 30 lb). Of that, 8.3 kg (62%) was fat and 5.3 kg (38%) was lean body mass.^[1]
• Lean mass includes more than muscle. Because muscle makes up about half of lean mass, the advisory estimates that about 20% of the total weight lost was muscle.^[1]
• Modeling cited in the advisory suggests that without structured strength training, muscle makes up about 10–15% of weight lost in women and 20–25% in men.^[1]

How much muscle you lose isn't fixed. The advisory notes that lean-mass loss is also affected by how hard you cut calories, how fast the weight comes off, and whether you do strength training.^[1] You have some control over all three.

Why does losing muscle matter?

Muscle does more than make you look fit. The advisory links low muscle and bone mass to physical impairment or disability, falls and fractures, surgical complications, lower quality of life, and shorter survival.^[1] It also notes that a randomized trial found GLP-1 therapy combined with exercise preserved bone mineral density, while GLP-1 therapy alone reduced it.^[1] For long-term health, the goal is to lose fat and keep your strength.

What exercise protects muscle on a GLP-1?

Strength training, done regularly and progressively. The advisory states that structured resistance training, or mixed resistance and aerobic programs, are "well established" to help preserve lean mass during weight loss. Aerobic exercise alone has a smaller effect.^[1] Its recommendation for people on GLP-1s:

• Strength training at least 3 times a week, plus
• at least 150 minutes a week of moderate-intensity aerobic activity (such as brisk walking),
• tailored to your current fitness and physical ability so you can stick with it.^[1]

For comparison, the general CDC guideline for all adults is 150 minutes of moderate activity plus muscle-strengthening on at least 2 days a week, working all major muscle groups.^[4] The GLP-1 advice raises strength training from 2 days to 3.

How much protein do I need on a GLP-1?

The baseline RDA for adults is 0.8 g of protein per kg of body weight per day. The advisory says higher targets of 1.2–1.6 g/kg/day have been proposed during active weight loss.^[1] Because it's unclear which body weight people with obesity should use, it also offers a simpler option: an absolute target of about 80–120 g of protein a day.^[1] It cautions against staying at or above 2 g/kg/day for long periods because of potential adverse effects, and notes that protein beyond what muscles need for repair or growth can be converted to fat by the liver.^[1]

Two practical points from the advisory: eat protein-rich foods first in a meal, when appetite is highest, and remember that protein without strength training is likely not enough to preserve muscle.^[1]

For a full breakdown by goal and body weight, see How much protein do I need a day?

What if nausea makes it hard to eat enough protein?

Gastrointestinal side effects are the most common problem with GLP-1s. In the trials summarized by the advisory, nausea affected 25–44% of participants.^[1] The advisory's practical strategies include:^[1]

• Smaller, more frequent meals. For example, a small breakfast and then small meals every 3–4 hours, with enough fluids.
• Avoiding fatty or high-fiber foods during the first few days of treatment.
• Watching for a cycle where not eating makes nausea worse, which in turn makes eating harder.
• Taking dehydration seriously. Severe nausea, vomiting, or diarrhea can lead to kidney injury.

How do I know if I'm losing muscle?

The scale can't tell you. The advisory recommends that care before and during GLP-1 treatment include assessment of muscle strength, physical function, and body composition.^[1] In practice:

• Track your strength. Keep a simple training log. If the weights you lift hold steady or go up while your body weight drops, that's a good sign.
• Track function. Notice whether stairs, carrying groceries, and getting up from the floor feel easier or harder.
• Ask about body-composition testing, such as a DXA scan, if your clinician thinks it would change your plan.

Does it matter which GLP-1 I'm on, or where it comes from?

Which medication you take, and at what dose, is a decision between you and your prescriber. According to the NIH's NIDDK, Wegovy (semaglutide) and Zepbound (tirzepatide) are FDA-approved for chronic weight management. Ozempic (semaglutide) and Mounjaro (tirzepatide) are approved for type 2 diabetes.^[2] NIDDK also says that weight-management medications don't replace physical activity and healthy eating, and that they work best combined with a lifestyle program.^[2]

On compounded versions, the FDA is direct: compounded drugs are not FDA-approved, and the agency does not review them for safety, effectiveness, or quality before they're sold.^[3] The FDA lists, as a telehealth red flag, any company that claims a compounded drug is the same as an FDA-approved drug.^[3] Buy only from a pharmacy your clinician approves.^[2]

A Simple Weekly Starting Template

This is an example of how the guidelines above can fit into a week. It isn't a prescription. Adjust it for your fitness level and check with your clinician if you have health conditions.

Every day: eat a protein-rich food first at each meal, spread across 3–4 meals or snacks. That gives you three strength days plus about 150 minutes or more of walking, which matches the advisory's minimums.^[1]