Tirzepatide vs Retatrutide
This matchup is really 'now vs later.' Tirzepatide is the most effective FDA-approved GLP-1-class drug you can get today. Retatrutide is an investigational triple agonist with the highest weight loss seen in trials — but it is not approved and not legally available. For anyone choosing treatment now, that decides it.
Last reviewed 2026-09-01 by the TopGLP1 Editorial Team
Educational, not medical advice. This page explains GLP-1 medications in general terms. Only a licensed clinician who knows your history can decide what's right for you.
Tirzepatide wins by default for anyone seeking treatment today — retatrutide is investigational and cannot be legally or safely obtained. Watch retatrutide's phase-3 results for the future.
Choose Tirzepatide if…
you want effective, FDA-approved treatment you can actually start now.
Choose Retatrutide if…
you're tracking the research — but it isn't an option to use yet.
Side by side
| Tirzepatide | Retatrutide | |
|---|---|---|
| Mechanism | Dual GIP/GLP-1 | Triple GIP/GLP-1/glucagon |
| Avg. weight loss | ~15–21% (SURMOUNT-1) | ~24% at 48 wks (phase 2) |
| Approval status | FDA-approved | Investigational (not approved) |
| Availability | Available now | Clinical trials only |
| Route | Weekly injection | Weekly injection (in trials) |
How they compare on results
On the numbers, retatrutide's phase-2 trial reported the highest average weight loss of any drug in this class — around 24% at 48 weeks at the top dose — edging tirzepatide's ~21%. Its added glucagon activity is thought to raise energy expenditure on top of appetite suppression.
But early phase-2 data are not a finished safety and efficacy picture, and retatrutide has not completed phase-3 or been approved. It cannot be legally prescribed or compounded — anything sold online as 'retatrutide' is unregulated and dangerous. Tirzepatide is the effective option you can actually and safely use today.
Side effects & safety
Tirzepatide's safety profile is established (GI side effects, class warnings). Retatrutide's full safety profile is still under study — one of the main reasons approval takes years.
Cost
Tirzepatide is available branded (~$1,000+/mo) or compounded ($119/mo at Embody). Retatrutide has no legal market and no legitimate price.
Full drug guides
Tirzepatide vs Retatrutide: common questions
Sources & references
Clinical figures on this page trace to peer-reviewed trials and official regulators. We link the primary record so you can verify it yourself.
- 1.Jastreboff AM, et al. Tirzepatide Once Weekly for the Treatment of Obesity. N Engl J Med. 2022;387(3):205–216.Clinical trialNew England Journal of Medicine
- 2.Jastreboff AM, et al. Triple–Hormone-Receptor Agonist Retatrutide for Obesity — A Phase 2 Trial. N Engl J Med. 2023;389(6):514–526.Clinical trialNew England Journal of Medicine