Explainers

The WHO's first global GLP-1 obesity guideline makes two conditional recommendations on moderate-to-low certainty evidence. Who it covers, and who it does not.

Two people can take the same GLP-1 weight-loss drug, follow the same instructions, and get completely different results. Three publications in the same week September 2026 converge on one bottom line: people's responses to these medicines vary widely, and much of that variation — like part of the drugs' heart protection — remains unexplained.

Pooled evidence from 37 studies and two withdrawal trials: about 0.4 kg regained per month after stopping (0.8 kg after semaglutide or tirzepatide), most lost weight typically returning within about a year, with cardiometabolic gains fading alongside — plus what remains projected, not measured. About 0.4 kg (about 0.9 lb) regained per month after stopping weight-loss medications — 0.8 kg (about 1.8 lb) after semaglutide or tirzepatide — and cardiometabolic gains fade too.