What is the average GLP-1 weight loss?

Results varied widely around every average

In STEP 1, 50% of participants lost 15% or more of their body weight while about one in seven did not reach 5%, all on the same dose and protocol. A single average hides that spread in both directions.

Being below an average is not a verdict

If your percentage is under the figure for your medication, that is information worth bringing to an appointment rather than a measure of how hard you have tried.

Trials are not directly comparable to each other

These trials differ in length, dose, who was enrolled and how much diet and exercise support everyone received. Comparing one trial’s number with another’s is rough, and comparing either with your own result is rougher still.

Your body burns less energy at a lower weight

A smaller body naturally needs fewer calories. Weight loss can also cause your body to conserve energy and increase hunger. This means the same food and activity habits that helped you lose weight earlier may eventually maintain your weight instead, causing weight loss to slow or stop.

A plateau does not always mean the medication has stopped working

A plateau can happen even while a GLP-1 medication is still having an effect. As weight decreases, the body generally needs less energy, and changes in appetite, activity, and energy use can slow further weight loss. Individual responses vary, though, and a prescriber can help determine whether the medication is still providing benefit.

Appetite signals can stay changed for at least a year

Sumithran and colleagues followed people for one year after diet-induced weight loss and found ghrelin still elevated and leptin still suppressed at that point. That study did not involve GLP-1 treatment, and it did not follow people beyond a year, so it describes what happens after weight loss rather than what a medication does to those signals.

Trial participants plateaued too, and earlier than you might expect

A post-hoc analysis of SURMOUNT-1 and SURMOUNT-4 measured when tirzepatide participants stopped losing. Median time to plateau ran from about 24 weeks in the overweight group to about 36 weeks in the highest BMI groups, and by week 72 roughly 88 to 90% had reached one. Higher doses, younger age and female sex were associated with plateauing later, and timing varied between individuals.

Raising the dose

In SURMOUNT-1, groups assigned higher doses of tirzepatide lost more on average, 15.0% at 5 mg against 20.9% at 15 mg. Those people were put on their dose at the start. No trial has taken people who stopped losing and raised it to see what happens.

The closest finding is that higher doses were associated with reaching a plateau later, which is an observation from inside the trials rather than a test of escalating.

Switching medication

SURMOUNT-5 compared tirzepatide with semaglutide directly and found 20.2% against 13.7% at 72 weeks. Everyone in it started fresh on one or the other. It shows the two differ on average. It does not show that moving from one to the other restarts a stalled result.

Adding a second medication

The only randomized attempt gave phentermine on top of liraglutide to 45 people for 12 weeks, after a year of treatment. The added-medication group lost 1.6% against 0.1% on placebo, which did not reach statistical significance. The rest of the published work on combining is animal studies, trials about maintaining a loss, or expert opinion.