Health Library / Hormones
This content is for education only and is not medical advice. I'm a fitness coach, not a physician. Talk to your doctor before starting any medication, hormone, supplement, or new exercise program, especially if you have a medical condition or take prescriptions.
More of my clients are on one of these than aren't, some weeks. And the conversation I keep having isn't about whether to take it. That's between them and their doctor, and I stay out of it.
The conversation is about what the scale isn't telling them.
When you lose weight — any way, at any age — some of what you lose is fat and some is lean tissue. Muscle, and the bone and connective tissue that come with it. That's always been true. Crash dieting has always done this.
With GLP-1 medications, the trial data suggests a meaningful share of total weight lost is lean mass. The figures reported across studies vary, and depending on the trial and how it's measured you'll see numbers in the range of a quarter to something closer to forty percent. Call it "a lot more than people assume."
For a 35-year-old that's a problem you can fix later. For someone at 55, that's different math. You were already losing muscle to age. Now you're losing it faster, and every pound of muscle you give up makes the next decade harder — your metabolism, your balance, your ability to get off the floor, your odds after a fall.
And here's the part that makes it sting: if you regain weight later, which plenty of people do when they stop, the regain is mostly fat. You don't automatically get the muscle back. Run that loop twice and you can end up at the same weight with a worse body composition than you started with.
Let me be clear about where I sit. Whether you take one of these, which one, how much, how long — all of that is your physician's call and I don't touch it. I won't discuss doses. I won't discuss where to get them, and I've got nothing to say about compounded versions or anything bought online except that it's a conversation for your doctor, not for me.
What I do have is the other half of the problem. These medications are extremely good at reducing how much you eat. They are not designed to tell your body which tissue to give up. That part is on training and protein, and that's my job.
The people who come out of this best are the ones treating the medication as one part of a plan rather than the whole plan.
Resistance training, throughout. Not after you hit your goal weight — during. Your body sheds what it isn't using. Loading a muscle is the signal that says keep this. Two to four sessions a week covering the whole body, with enough challenge that the last couple of reps are genuinely hard. This isn't the moment for light circuits and long walks alone. Walking is excellent and it doesn't send the signal we need here.
Protein, deliberately. This is where the medication works against you, because appetite suppression makes it very easy to end the day at half the protein you need without noticing you were hungry. When intake drops, protein has to be the thing you protect, not the thing that falls off first. Older adults already need more protein per meal to get the same muscle-building response. Eating less overall makes hitting that harder, not easier.
Practically: build meals around the protein and let the rest fill in. If you're only going to manage two real meals, both of them have a protein anchor. Tell your doctor or a dietitian what you're actually eating — not what you meant to eat — because they can help you fit it into a much smaller appetite.
Most people on these drugs get weighed. Far fewer get body composition measured. If you can get a DEXA or something comparable before and during, you'll know whether you're losing the right tissue instead of guessing from a number that can't tell the difference.
That's worth asking your doctor about. It changes what "it's working" means.
These medications have helped people who'd been fighting their weight for thirty years, and I'm not going to be precious about that. What I'd hate is watching someone hit their goal weight at 58 and arrive there weaker than they left.
Lift while you lose. Eat the protein. Let your doctor handle the medicine.
Last updated September 30, 2026