# A weekly injection of 12 milligrams (0.19 grain) of retatrutide for 80 weeks helped people lose almost 30 percent of their body weight.

*biotech · news · 2026-05-21 · Scientific American*

## Key points

- Retatrutide helped participants lose almost 30 percent of body weight over 80 weeks in a phase 3 trial.
- Retatrutide targets three receptors—GLP-1, glucagon, and GIP—unlike current drugs targeting one or two.
- At the highest dose tested, participants lost 28.3 percent of their body weight on average.
- About one-third of participants experienced nausea or diarrhea, while up to a quarter experienced vomiting.

**Companies:** Eli Lilly
**Countries:** United States

[Read the full story on Scientific American](https://www.scientificamerican.com/article/next-gen-weight-loss-drug-retatrutide-trial-brings-it-one-step-closer-to-fda-approval/)

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