How long do you have to stay on a GLP-1?

There is no course length. A GLP-1 is not an antibiotic. The 2026 American Diabetes Association standards put it directly: continue obesity medications after reaching treatment goals to maintain health benefits, since discontinuation often results in weight recurrence and worsening or reemergence of cardiometabolic risk factors. The World Health Organization's December 2025 guideline conditionally recommends GLP-1 therapies for the long-term treatment of obesity in adults.

What happens when treatment stops

Two trials answer this cleanly. In the STEP 1 extension, participants who had lost 17.3 percent of their weight over 68 weeks on semaglutide regained 11.6 percentage points of it in the year after stopping, ending at 5.6 percent below their starting weight, with cardiometabolic improvements reverting towards baseline. In SURMOUNT-4, participants who stopped tirzepatide after 36 weeks and were followed for a further 52 weeks regained substantially: 82 percent of the placebo group regained more than a quarter of the weight they had lost, and a post hoc analysis showed waist circumference, blood pressure, non-HDL cholesterol and HbA1c all deteriorated in step with the amount regained.

Why this is biology rather than a failure of resolve

The medication suppresses appetite signalling while it is present. Removing it restores the appetite signalling that was there before, in a body that is now smaller and burning less energy at rest. That is a pharmacological effect ending, not a character flaw appearing. The same is true of any chronic disease treatment: nobody expects blood pressure to stay down after the ramipril stops.

When stopping is a reasonable decision

Stopping is right when the drug is not working, when side effects outweigh benefit, when pregnancy is planned, or when the original driver of weight gain has been fixed and the patient wants to test whether the medication is still needed. The Endocrine Society advises discontinuing an obesity medication if weight loss is under 5 percent at three months on an adequate dose. Cost and access also end treatment in practice, and that deserves an honest plan rather than an unplanned stop.

Ask your prescriber to state explicitly whether the intention is indefinite treatment, a defined trial of stopping with monitoring, or a step down to a lower maintenance dose. Any of those can be right. Not knowing which one you are on is what leads to an abrupt, unsupported stop and a fast regain.