Evidence-graded answer
Will I regain weight after stopping GLP-1?
Most people regain about two-thirds of lost weight within 1 year of stopping, based on STEP-1 extension and STEP-4 withdrawal data. Continued lifestyle support reduces the rebound. Most clinicians now treat obesity as a chronic condition requiring ongoing treatment, similar to hypertension.
STEP-1 extension (semaglutide stopped at week 68): mean regain of two-thirds of lost weight at 1 year off-drug.
SURMOUNT-4 (tirzepatide withdrawal): patients switched to placebo regained ~14% of body weight at 88 weeks vs continued-treatment group, who maintained loss.
For most patients planning to stop, the realistic frame is: weight loss is durable while on-drug, partially durable in the months after stopping, and largely reverses by 12-24 months without ongoing pharmacotherapy or sustained behavior change.
Source: SURMOUNT-4 JAMA 2024, JAMA