FAQ · GLP-1 · Editorial commentary

What does the published evidence report about weight regain after stopping Mounjaro?

Editorial commentary on the published literature. Published trial data and observational cohort analyses report that a substantial proportion of patients regain weight after stopping GLP-1 medications, including tirzepatide. The SURMOUNT-4 trial reported significant weight regain in the cohort that switched from tirzepatide to placebo compared with the cohort that continued. UK observational analyses have reported similar findings. Whether to stop, continue, or transition to a lower maintenance dose is a clinical decision between the patient and their UK-licensed prescriber. This page summarises the published evidence and does not constitute individual clinical advice.

What the published trial evidence reports

SURMOUNT-4, published in JAMA in 2024, randomised patients who had reached a stable weight on tirzepatide either to continue the medication or to switch to placebo. The cohort that continued tirzepatide maintained or slightly extended their weight loss. The cohort that switched to placebo regained a substantial proportion of the weight lost during the open-label phase. The published trial established that tirzepatide\'s effect on weight is maintained during continued use and diminishes after discontinuation. Similar findings have been reported in the STEP trial programme for semaglutide.

What the published mechanistic literature describes

Published mechanistic literature describes three factors that contribute to weight regain after stopping any pharmacological weight-loss treatment. First, adaptive thermogenesis reduces resting metabolic rate beyond what body-size shrinkage alone would predict. Second, hormonal appetite signalling (including ghrelin) rebounds once GLP-1 receptor agonism stops. Third, behavioural and environmental factors that drove the original weight gain remain present after the medication is withdrawn. These three factors are discussed in published reviews on the physiology of weight regain.

What the lifestyle literature reports on regain mitigation

Published literature on weight-loss maintenance, including the National Weight Control Registry analyses and randomised trials of post-loss maintenance, reports that adequate protein intake, regular resistance training, sufficient sleep, and consistent low-intensity movement are associated with better preservation of weight loss. These are general lifestyle observations from the published maintenance literature. Specific targets (protein intake, training volume, step counts) for an individual should be set with the patient\'s prescriber, dietitian, or physiotherapist where relevant, not from a general website.

Maintenance dosing as a published clinical concept

Editorial note. Some UK prescribers transition patients to a lower ongoing dose of tirzepatide rather than full discontinuation at goal weight. This is discussed in published clinical commentary as an emerging area of practice. It is not part of the MHRA-licensed indication wording, and the decision to use a lower maintenance dose, or to stop completely, is a clinical decision between the patient and the prescriber. PeptideClear does not publish dosing recommendations.

Where to ask

• · Your prescriber. NHS GP, NHS Specialist Weight Management Service, or private clinic prescriber.
• · An NHS or HCPC-registered dietitian, for individualised nutrition guidance during and after GLP-1 treatment.
• · The published SmPCs and PILs on emc.medicines.org.uk.

Related: Aftercare hub · Protein on GLP-1 · Muscle preservation · RMR.