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GLP-1 Weight Regain Calculator: What Happens If You Stop
Stopping a GLP-1 usually means some weight comes back, because the medication treats an ongoing condition rather than curing it. This calculator estimates how much, using the STEP 1 trial extension as its anchor: participants regained roughly two-thirds of the weight they had lost within a year of stopping. Enter what you lost and how long since you stopped to see an average projection.
Weight Regain After Stopping
Projected regain
about 67% of what you lost
- Net still off
- 10 lb
Based on the STEP 1 extension, where people regained about two-thirds of their lost weight within a year of stopping semaglutide. This is a population average ramped over 12 months, not a prediction for you: continued diet and activity, and in some cases a maintenance dose, substantially reduce regain. Educational only, not medical advice.
The hardest truth about GLP-1 medications is that stopping usually undoes part of the progress. These drugs lower appetite while they are in your system; they do not permanently reset it. So the honest question is not whether some weight returns, but how much, and what changes the answer. This calculator gives an evidence-anchored estimate.
Where the number comes from
The anchor is the extension of the STEP 1 trial, the pivotal study of semaglutide for weight loss. After participants stopped the medication, they regained about two-thirds of the weight they had lost within a year, and much of the metabolic improvement reversed alongside it. The calculator applies that two-thirds fraction to whatever you lost, spread roughly evenly across twelve months, to show an average trajectory. Our full explainer on weight regain after stopping Ozempic covers the study in detail.
Why the body pushes weight back up
Regain is not a willpower problem. Obesity behaves like a chronic condition, and the body actively defends a higher weight through hunger hormones and a lowered metabolic rate, a set of mechanisms explained in our piece on why keeping weight off is biologically harder. A GLP-1 counteracts those signals; remove it and they reassert themselves. That is the physiology the trial captured.
What changes the outcome
The two-thirds figure describes people who stopped entirely. It is not fixed. Continuing the habits built during treatment, keeping protein high, maintaining resistance training, and protecting sleep all blunt regain. Many people also stay on a lower maintenance dose rather than stopping outright, which holds results far better. Our guide on how to stop a GLP-1 without regaining weight lays out the practical options to discuss with your clinician.
How to read the result
Use the projection as a planning tool, not a prophecy. It is deliberately conservative and average; your result depends heavily on what you do after stopping and on decisions, like tapering versus continuing a maintenance dose, that belong with your prescriber. The point is to go in with realistic expectations and a plan, rather than being surprised. Not medical advice.
Frequently Asked Questions
How much weight do people regain after stopping a GLP-1?
In the STEP 1 trial extension, participants regained about two-thirds of the weight they had lost within one year of stopping semaglutide, on average. This calculator applies that fraction, so someone who lost 30 pounds would be projected to regain about 20 over that year, with a net loss of about 10 still kept off.
Why does weight come back after stopping?
GLP-1 medications work by lowering appetite while you take them. They treat obesity as a chronic condition rather than curing it, so when the drug leaves your system appetite and the body's weight-defense mechanisms return, and weight tends to drift back up. This is expected and not a personal failure.
Can you avoid regaining the weight?
You can substantially reduce it. Continued attention to diet, protein, resistance training, and sleep all help, and some people stay on a lower maintenance dose to hold their results. The trial figure is an average for people who stopped entirely; individual outcomes vary widely with what you do next.
Is the two-thirds figure a guarantee?
No. It is the average from one large trial, ramped roughly evenly over a year for illustration. Your own regain depends on your habits after stopping, whether you taper or continue a maintenance dose, and individual biology. Treat the number as a reference point, not a forecast.
Not medical advice. This resource is for general education only. Medications, dosing, and treatment suitability are decisions for you and a licensed clinician who knows your full medical history.
Last updated · 5 min read
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