Injectable division
Retatrutide
AClass-leading
Eli Lilly · certified
vs
Injectable division
Tirzepatide (Zepbound)
Class-leadingA
Eli Lilly · approved
21% · a hair ahead
Efficacy
18%
Notable (+6.4)
Tolerability
gentler · Mild (+3.6)
Subcutaneous injection
Route
Subcutaneous injection
None
Food / water rule
None
Refrigerated
Storage
Refrigerated (room temperature up to 21 days)
The call: The frontier of the injectable class, and closer than the raw numbers suggest: both are class-leading, retatrutide a step ahead on magnitude. But tirzepatide is published and approved, while retatrutide is a topline that is not yet peer-reviewed or cleared. Tirzepatide is also the gentler of the two. So the confident pick today is tirzepatide; retatrutide is the one to watch when its Phase 3 is published.
Standalone, this page carries its own key: Efficacy = % body weight lost vs placebo, on the conservative estimand that counts everyone. Tolerability = AE-discontinuation over placebo (Mild 1 to 5 · Notable 5 to 10 · Heavy over 10 points). Winners are called only across a tier or band boundary; within one, the drugs are effectively tied. The side marked leads or gentler wins that axis.
Retatrutide verdict · Tirzepatide verdict · How this is scored