Adds a second incretin receptor to the same basic idea, and the extra pathway shows up clearly in the trial results.
what it is
Tirzepatide activates two receptors rather than one: GLP-1, as semaglutide does, and also GIP, a second incretin hormone. GIP's contribution was long considered marginal or even counterproductive for weight, so the fact that adding it improves outcomes was a genuine surprise and is still not fully explained mechanistically.
what the evidence shows
The SURMOUNT trials reported mean weight reductions above twenty per cent at the highest doses over seventy-two weeks — the largest figures any pharmacological approach has produced outside surgery. A head-to-head trial against semaglutide favoured tirzepatide on weight endpoints. It also carries approval for type 2 diabetes and, more recently, obstructive sleep apnoea in people with obesity.
Adds a second incretin receptor to the same basic idea, and the extra pathway shows up clearly in the trial results.
what stays uncertain
Everything said about the class applies here: regain after discontinuation, lean mass loss, and gastrointestinal tolerability. Because it arrived later, the long-term safety record is shorter than semaglutide's. The dual mechanism means less accumulated clinical familiarity with edge cases and interactions.
the practical note
Tirzepatide is not interchangeable with semaglutide on a milligram basis, and dose conversions circulating on forums are not derived from any published equivalence study. The titration schedules in the trials were slow for a reason — tolerability, not caution theatre.