How Long Does It Take to Lose Weight on a GLP-1?

Short answer: weight loss on GLP-1 medications is fastest in the first few months, then gradually slows as the body approaches a plateau. In published trials, that plateau is typically reached around 60-72 weeks, not weeks or days.

The general shape of the curve

Rather than a straight line, weight loss on GLP-1 medications tends to follow an approach-to-plateau curve: significant loss early on, with the rate slowing month over month as you get closer to your body's response ceiling for that medication and dose. This pattern shows up consistently across both the STEP 1 (semaglutide) and SURMOUNT-1 (tirzepatide) trial data.

Why it's not a straight line

It's common to lose weight quickly in the first month, then feel like progress has "stalled" a few months in. That's expected, not a sign the medication has stopped working. The rate of loss slows well before most people reach their personal goal weight, which is part of why realistic timeline expectations matter.

What determines your own timeline

Your starting weight, your goal weight, and which medication you're using all affect how many months it could take to reach your goal. A licensed provider can factor in your full medical history; our calculator estimates a timeline based on your weight numbers and published trial averages.