Semaglutide vs Tirzepatide

Semaglutide

The GLP-1 receptor agonist that turned obesity pharmacology into a mainstream conversation. Once-weekly injection, ~7-day half-life, and the largest randomised dataset of anything in this catalogue.

Best for

Best if you have a stable weight-loss trajectory and want the better-studied option with more long-term cardiovascular data.

Tirzepatide

Dual GIP and GLP-1 agonist. Beats Semaglutide head-to-head on weight loss and glycaemic control, and is becoming the default first-line choice when both are available.

Best for

Best if Semaglutide has stalled, or if you need stronger appetite suppression and can tolerate slightly worse GI side effects early.

Semaglutide

Approved by the FDA and EMA for type 2 diabetes (Ozempic, Rybelsus oral) and chronic weight management (Wegovy). The STEP 1–8 obesity trials and the SUSTAIN diabetes programme together represent tens of thousands of randomised patient-years. SELECT (2023) added cardiovascular outcomes — a 20% reduction in MACE in patients with obesity and established CVD. This is the most thoroughly characterised peptide on this site by an order of magnitude.

Tirzepatide

FDA-approved 2022 for type 2 diabetes (Mounjaro) and 2023 for chronic weight management (Zepbound); EMA approval followed. The SURPASS 1–5 diabetes trials and SURMOUNT 1–4 obesity trials constitute the largest randomised dataset of any dual incretin. SURMOUNT-1 vs STEP 1 is the cleanest head-to-head proxy, and SURPASS-2 was a direct comparison: Tirzepatide came out ahead on both weight and HbA1c.