How to keep muscle on Zepbound, Wegovy or Ozempic

Short answer: eat enough protein every day and lift something two or three times a week, adding a little volume or weight as you get stronger. Those two habits are what the evidence and the major obesity and nutrition societies point to for protecting muscle while a GLP-1 medication takes the weight off.

How much of the weight is muscle?

Not all weight lost is fat. In the body-composition substudies of the main trials, lean mass made up roughly 40% of the weight lost on semaglutide (STEP 1, the Wegovy trial) and roughly a quarter on tirzepatide (SURMOUNT-1, the Zepbound trial). Lean mass is more than muscle (it includes water and organs), so these figures overstate pure muscle loss, but the direction is clear: the faster and larger the weight loss, the more there is to protect.

That matters because muscle is what keeps you strong, steady on your feet and able to do the things you lost the weight for. It also matters more with age, when muscle is harder to rebuild.

What protects it

Resistance training. In a year-long trial of dieting older adults with obesity, the groups that lifted lost markedly less lean mass than the group that only did aerobic exercise, and the group that did both improved physical function the most. A 2025 joint advisory from four US obesity and nutrition societies lists resistance training and adequate protein as the priorities for preserving muscle and bone during GLP-1 treatment.

Enough protein. Appetite falls on a GLP-1, and protein is usually the first thing to fall short. See how much protein you need.

Progression. Muscle responds to work that is slightly harder than last time. More weekly sets per muscle group builds more muscle, with about ten hard sets per muscle a week as a useful target once you have built up to it.

A simple starting point

• Two or three short strength sessions a week, whole body each time.
• Start with one or two sets of each movement at a weight that feels easy, and build up to three sets over a few weeks.
• Add a little weight only when you finished every rep last time.
• Walk on the other days. Exercise combined with a GLP-1 kept more weight off than either alone in a 2021 trial.

The beginner plan lays this out week by week.