6 things to know about protecting your muscle on a GLP-1

In the SURMOUNT-1 tirzepatide trial’s scan substudy, roughly a quarter of the weight lost was lean tissue.^3,4

Some context, because it matters: “lean mass” isn’t all muscle. It also includes water, organs and other non-fat tissue. Experts estimate muscle makes up around half of it.² Losing some lean mass is expected with any significant weight loss. The goal is to protect as much muscle and strength as possible.

In 2025, four US obesity and nutrition organisations published a joint advisory on supporting GLP-1 therapy. It lists muscle and bone loss among the main challenges, and recommends preserving muscle and bone through resistance training and an appropriate diet.²

Ask for a strength and body-composition check when treatment starts.

The advisory suggests checking muscle strength, function and body composition at the start of treatment. It’s a good question to bring to an appointment.

When appetite shrinks, protein is often the first thing to slip. The advisory notes the standard recommendation of 0.8 g per kg of body weight a day, and that higher targets, such as 1.2–1.6 g/kg/day, have been proposed during active weight loss.²

• Start meals with the protein (eggs, fish, chicken, tofu, Greek yoghurt, legumes).
• Spread it across the day instead of saving it for dinner.
• Ask a doctor or dietitian what target suits you.

Of everything you can do, resistance training has the strongest case for protecting muscle during weight loss.^2,5 Two or three short sessions a week is a realistic place to start: squats to a chair, wall push-ups, bands, light dumbbells or a guided strength class.

A 2026 review of strategies to preserve lean mass during GLP-1 treatment describes creatine monohydrate as having “one of the stronger indirect evidence bases” among muscle-focused supplements. It also notes the evidence is not GLP-1-specific.⁵

Most of that evidence comes from older adults. When they combined creatine with resistance training, they gained more lean tissue and strength than with training alone.⁶*

Creatine works by building up in your muscles with daily use: 3–5 g a day raises stores over roughly 3–4 weeks.⁷ So whatever you choose has to be easy to stick with.

On days when big meals and big drinks feel like a lot, small habits win. Pair anything new with a meal you already eat, and keep it simple enough to do every day.