How Long Does It Take to Lose 100 Pounds on a GLP-1?

Short answer: using average results from published clinical trials, losing 100 pounds takes more than 24 months on semaglutide and more than 24 months on tirzepatide, depending on your starting weight. Someone starting at 350 pounds and aiming for 250 would need to lose 28.6% of their body weight, which our model projects at 24+ months on semaglutide and 24+ months on tirzepatide.

At this size of goal, average trial results do not reach the target within two years for either medication. A loss this large is a bigger share of body weight than the trials averaged, so it is worth discussing realistic targets and timelines with a licensed provider.

Estimated time to lose 100 pounds by starting weight

"24+ months" means the goal is not reached within the 24-month window our model covers. Estimates use the average outcomes from the STEP 1 (semaglutide) and SURMOUNT-1 (tirzepatide) trials and are not a prediction for any individual.

Why the same 100 pounds takes different amounts of time

Trial results are reported as a percentage of starting body weight, not a fixed number of pounds. Losing 100 pounds is a smaller share of body weight for someone who starts heavier, so it can be reached sooner, while the same 100 pounds is a much bigger share for someone lighter. Loss is also fastest early on and slows as it approaches a plateau, so the last few pounds take disproportionately longer.

Get your own estimate

The table uses round starting weights. Enter your exact current weight and goal weight in the calculator to see a month-by-month timeline for both medications.