What is the difference between semaglutide and tirzepatide?

Semaglutide acts at the GLP-1 receptor. Tirzepatide is a dual agonist acting at both GIP and GLP-1 receptors. Both are given as weekly injections with a stepwise titration and both carry the same boxed warning regarding thyroid C-cell tumours. Which is appropriate depends on your history, tolerability, contraindications and availability — that is a clinical judgement, not a preference.