A major review from Oxford University, published in The BMJ, examined what happens when people discontinue popular weight-loss medications like semaglutide (sold as Ozempic and Wegovy) and tirzepatide (Mounjaro, Zepbound). The study analyzed 37 clinical trials and observational studies covering 9,341 participants.
The key finding: after stopping weight-loss drugs, participants regained an average of 0.4 kg (0.9 lbs) per month. For the newer drugs specifically, regain was even faster — 0.8 kg (1.8 lbs) per month. At these rates, researchers projected a return to pre-treatment weight within 1.5 to 1.7 years.
The regain rate was nearly four times faster than weight regain after ending behavioral programs (diet and exercise). However, this comparison came from a different study — the medication users and diet program users were never directly compared in the same trial. This is an important limitation because the two groups may differ in many ways.
Health benefits also reversed. Improvements in blood sugar, blood pressure, and cholesterol were projected to disappear within 1.4 years.
Other limitations include: only 8 of 37 studies examined the newer GLP-1 drugs (a newer type of weight-loss medication), no study followed people beyond 12 months after stopping, and the longer-term projections are mathematical estimates rather than observed outcomes. The reasons people stopped taking the drugs (side effects, cost, personal choice) were not always distinguished, and these reasons could affect how much weight they regained.