Tirzepatide vs Retatrutide
Dual vs triple agonist — and whether the extra glucagon arm is worth waiting for
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 you want the proven, approved option with five years of post-launch data.
Read full pageRetatrutide
Triple agonist hitting GIP, GLP-1, and glucagon receptors at once. Phase 2 data shows the largest weight-loss numbers ever reported for a drug in trials — ~24% at 48 weeks.
Best for
Best if you are willing to wait for approval and want the highest-ceiling investigational option (~24% weight loss in Phase 2 at 48 weeks).
Read full pageKey difference
Retatrutide adds a glucagon-receptor arm on top of GLP-1/GIP, which raises resting heart rate noticeably. The efficacy gain over Tirzepatide is real but the safety dataset is much smaller.
Evidence quality
Tirzepatide
Regulator-approvedFDA-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.
Retatrutide
Phase 3 trialsPhase 2 results published in NEJM 2023 showed ~24% weight loss at 12 mg over 48 weeks. The TRIUMPH Phase 3 programme (TRIUMPH-1 through TRIUMPH-4) is enrolling and reporting through 2025–2026, covering obesity, type 2 diabetes, obstructive sleep apnoea, and knee osteoarthritis. No regulatory approval as of mid-2026. The dataset is strong but not yet at the size or duration where rare safety signals would surface.
Not sure which one fits? Open both full pages and read the contraindications first — they are usually the deciding factor.