Overview
- In the phase 3 Triumph-4 study, a 12 mg weekly dose cut average body weight by 28.7% over 68 weeks and reduced knee osteoarthritis pain in a trial of more than 400 adults.
- Retatrutide targets GLP-1, GIP, and glucagon receptors, with reported weight loss exceeding late-stage averages for tirzepatide in separate studies.
- Doctors report gastrointestinal side effects and say long-term safety and durability of weight loss remain unestablished, and the drug is not FDA-approved.
- Eli Lilly plans seven additional phase 3 readouts in 2026 across obesity and type 2 diabetes that will shape potential filings and commercial strategy.
- Grey-market vendors are selling unapproved versions as “research chemicals,” and Lilly says any product claiming to be retatrutide for human use is illegal.