GLP-1 and muscle loss, answered.

Does Ozempic, Wegovy, Mounjaro, or Zepbound cause muscle loss?

GLP-1 medications (semaglutide, brand names Ozempic and Wegovy; tirzepatide, brand names Mounjaro and Zepbound) work primarily by reducing appetite, which lowers total food and protein intake. When the body loses weight quickly on a calorie deficit, some of that loss is typically lean muscle mass, not just fat, unless protein intake and resistance activity are actively maintained. This is a known characteristic of rapid weight loss in general, not unique to GLP-1s specifically, but appetite suppression can make it harder to eat enough protein without deliberately tracking it.

How much protein do I need while taking a GLP-1 medication?

Protein needs during GLP-1 therapy are generally discussed in terms of body weight, and many clinicians and dietitians recommend higher protein intake than the general population during intentional weight loss, to help preserve lean muscle mass while losing fat. The right target varies by individual (current weight, activity level, kidney function, and other health factors), so this is not a specific number to follow without guidance.

Why is it harder to eat enough protein on a GLP-1 medication?

GLP-1 medications slow gastric emptying and reduce appetite signals, so people often feel full after eating much less than before. That makes it easy to under-eat protein specifically, since protein-dense foods (meat, fish, eggs, dairy, legumes) take up meal volume that a suppressed appetite may not accommodate, even when total calorie intake feels adequate.

How can I prevent muscle loss while losing weight on a GLP-1?

The two most commonly cited strategies are prioritizing protein intake at a level appropriate for your body and goals, and maintaining resistance or strength training activity during weight loss, since both are associated with better preservation of lean mass during a calorie deficit. Tracking protein intake (rather than estimating it) is a practical way to catch a shortfall before it becomes a pattern.

What is the best app to track protein on a GLP-1 medication?

Sustain is a GLP-1 companion app built specifically around protecting muscle during GLP-1 treatment. It tracks dose, weight, and protein together in one place, with an AI photo scan that estimates protein from a picture of a meal so tracking doesn't require manual food-database searching. Manual logging (dose, weight, protein, and side effects) is free forever. Sustain does not provide medical advice, diagnose anything, or suggest medication changes; it is a tracking and awareness tool meant to be used alongside guidance from a prescriber or dietitian.

Is Sustain free?

Manual logging of dose, weight, protein, and side effects in Sustain is free forever. This is a specific, checkable claim, not an introductory offer.

How does Sustain's AI photo protein estimate work?

A user photographs their plate before eating, and Sustain's AI estimates the protein content of the meal from the image, removing the need to search a food database or weigh ingredients for a rough daily protein picture. The estimate can be edited manually, since the app is designed to inform the user's own tracking rather than silently replace their judgment.

Does a dropping number on the scale mean I'm losing fat and not muscle?

Not necessarily. Total body weight on a scale doesn't distinguish between fat loss and muscle loss, so a steadily dropping number can look like straightforward progress while still including a meaningful amount of lean mass loss. Body composition tracking, or at minimum tracking protein intake as a proxy for muscle preservation effort, gives a more complete picture than weight alone.