GLP-1 Stop and Weight Regain Calculator
Stopping a GLP-1 medication is common, and so is regaining some of the weight. The follow-up phases of the big trials tracked what happened next: after stopping semaglutide, participants regained about two thirds of their lost weight within one year, and after stopping tirzepatide, about half. This calculator applies those published follow-up patterns to your numbers to estimate where your weight could be now.
How this estimate works
The model starts from the one year follow-up figure for your medication. In the STEP 1 trial extension, participants who stopped semaglutide regained about two thirds of their lost weight within a year, an endpoint of about 67 percent of the loss. In SURMOUNT-4, participants who switched from tirzepatide to a placebo regained about half of their lost weight over the following year, an endpoint of about 50 percent.
Between stopping and the one year mark, the calculator grows the regained share along a square root curve, so a larger share of the regain shows up in the earlier months and the pace eases later. At 3 months, for example, the curve reaches half of the one year share. Because individual results vary so widely, the results are shown as a range built by moving the curve ten percentage points in either direction, rather than as a single confident number.
What the follow-up studies also showed
The STEP 1 extension followed people for a year after their last semaglutide dose. Alongside the weight regain of about two thirds of the loss, many of the health improvements seen during treatment drifted back toward where they had started, which is part of why these medications are usually framed as long term treatments rather than short courses.
SURMOUNT-4 tells the other half of the story. After 36 weeks on tirzepatide, half of the participants switched to a placebo and regained about half of their lost weight over the next year, while the half who stayed on tirzepatide maintained their loss and on average lost a little more. The gap between the two groups is the clearest published picture of what stopping, versus continuing, tends to look like.
Across the follow-up reporting, one pattern is consistent: results varied a lot from person to person, and people who kept up the habits built during treatment, eating adequate protein, staying physically active, and keeping follow-up contact with their care team, tended to regain less than the average. That is a tendency seen in groups, not a promise for any individual.
Frequently asked questions
How much weight do people regain after stopping a GLP-1 medication?
On average, a lot of it. In the STEP 1 extension, people who stopped semaglutide regained about two thirds of the weight they had lost within one year. In SURMOUNT-4, people who switched from tirzepatide to a placebo regained about half of their lost weight over the following year. These are group averages, and individual results ranged widely in both studies.
How fast does the weight come back after stopping?
Regain starts as the medication effect wears off and appetite returns, and in the follow-up studies it was still continuing at the one year mark. The pattern is usually fastest in the first months and slower later, which is the shape this calculator uses, but your own pace depends on your habits, your dose history and how long you were treated.
Can weight regain after stopping be slowed down?
Nothing guarantees it, and you should be skeptical of any product that promises otherwise. The follow-up evidence suggests people who keep up the habits built during treatment, adequate protein, regular physical activity including resistance training, and ongoing follow-up with their care team, tend to regain less. Some people also talk with their doctor about maintenance dosing or other long term options instead of stopping completely.
Does everyone regain all of the weight?
No. Regaining everything is not inevitable, and at the one year follow-ups the average was partial regain, about half to two thirds of the loss, not all of it. Some participants kept most of their loss off, and others regained more than the average. Where you land depends on factors no calculator can see, which is why this tool shows a range rather than a single number.