People often ask how much weight a GLP-1 leads to. Clinical trials report average figures — but your own result depends on the drug, the dose you reach, how long you stay on it, and your diet and activity. These numbers are educational, not a promise.
These are averages from the manufacturers’ large trials, at the top studied doses, over roughly 15–18 months:
| Drug (weight-management use) | Average weight loss in trials |
|---|---|
| Semaglutide (Wegovy) | ~15% of body weight |
| Tirzepatide (Zepbound) | ~20% of body weight (higher at the top dose) |
| Retatrutide (investigational) | ~24% in trials — not FDA-approved |
An “average” means some people lost much more and some much less. A 15% average, for example, is roughly 30 lb for a 200 lb starting weight — but that is a group average, not a guarantee for any one person.
Some of the weight lost is muscle, not just fat; that is why strength training and protein matter. And most people hit a plateau at some point — that is normal.
In the Wegovy trials, participants lost about 15% of body weight on average over roughly 68 weeks. Individual results vary widely.
In the Zepbound trials, average loss was around 20% of body weight, higher at the top dose, over about 72 weeks. Results vary by person.
Gradually. Loss builds over many months as the dose is increased and maintained; trials ran a year or more.
Not necessarily — trial numbers are group averages. Your result depends on dose, time, diet, activity and consistency. Discuss realistic expectations with your doctor.
Yes, some weight lost is muscle. Strength training and adequate protein help protect muscle while you lose fat.