If you are losing weight on a GLP-1, it is working. The appetite drop is real and the metabolic benefits are well documented. What a short prescribing visit rarely covers is what else goes with the fat. Lean mass includes muscle, and muscle is what keeps you strong and steady on your feet. Once it is gone, it does not come back just because the scale stops moving.
Why muscle goes
It is not one thing. Reviews of GLP-1 patients point to several at once: eating less protein because appetite is low, a calorie deficit that pushes the body to break down tissue, hormone shifts, weaker muscle-building signals and faster protein breakdown.2 The appetite effect is large. In the trial that measured how semaglutide produces weight loss, total daily energy intake fell 24 percent.3
The cost shows up in function, not just in the mirror. A 24-month study of older adults with type 2 diabetes linked semaglutide to accelerated age-related muscle loss, measured by muscle mass, grip strength and walking speed.4
Lever one: protein, first, at every meal
The target I use is 1.6 to 2.0 grams of protein per kilogram of body weight per day, spread over three or four meals instead of saved for dinner.5 For someone who weighs 200 pounds, about 91 kg, that is roughly 145 to 180 grams a day. With a small appetite that is hard, so eat the protein first, before anything else on the plate. A shake can fill the gap on days you cannot eat enough.
If you have kidney disease, set your protein target with your physician rather than from this page.
Lever two: lift, three times a week
Resistance training at least three times a week, built on compound movements such as squats, rows, presses and hip hinges. Take each set to within two or three reps of failure, because easy sets do not send the signal. Get a protein-rich meal or shake within two hours afterward.5 If you have never lifted, a few sessions with a qualified coach to learn the movements is money well spent.
A smaller lever: omega-3
A 2023 meta-analysis found omega-3 supplements gave a very small but real benefit to muscle strength, with no meaningful effect on muscle mass overall.6 One trial in healthy adults aged 60 to 85 used about 3.4 grams a day of combined EPA and DHA for six months and found 3.6 percent more thigh muscle volume and 2.3 kg more grip strength than the control group.7 That dose is far more than a standard capsule, so check the label, and clear it with your prescriber first, especially if you take a blood thinner. Treat omega-3 as the garnish. Protein and training are the meal.
Eating less means fewer nutrients, too
Your calorie intake drops. Your need for vitamins and minerals does not. Reviews of GLP-1 therapy describe a recognizable pattern of shortfalls from sustained low intake.8 Thiamine, vitamin B1, is the one to watch, because the body stores little of it and levels can fall within weeks of poor intake, especially with nausea or vomiting.
Go to an emergency department the same day if you have had persistent vomiting or months of very low intake on a GLP-1 and then develop confusion, unsteadiness on your feet, or vision changes such as double vision. Say the words "possible thiamine deficiency." This can be Wernicke's encephalopathy, which is treated with IV thiamine and needs to be caught early. It is rare: one review found six published cases with semaglutide, and an FDA database analysis found fifteen across GLP-1 drugs.910 Rare is not never, and early treatment matters.
What this does not mean
None of this is a reason to stop your medication or change your dose. Those decisions belong with your prescriber. Protein, training and nutrient checks run alongside the prescription, so you come out the other side lighter and still strong.
Common questions
How much protein do I need on Ozempic or Zepbound?
The target I use is 1.6 to 2.0 grams per kilogram of body weight per day, over three or four meals. That works out to roughly 0.7 to 0.9 grams per pound. If you have kidney disease, check with your physician first.
Can I lose muscle on a GLP-1 even if I eat well?
Yes. Low protein intake is one driver, but the calorie deficit and hormone shifts contribute too, which is why resistance training matters as much as diet.
Should I stop my GLP-1 if I am losing muscle?
Not on your own. Talk to your prescriber, and start with protein and resistance training, the two levers with the best evidence behind them.