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Peptides, hormones and pipeline drugs

Retatrutide

Retatrutide is an investigational weekly injection from Eli Lilly that activates three hormone receptors: GIP, GLP-1 and glucagon. It is not FDA-approved.

Clinician review pending Updated Peptides, hormones and pipeline drugs
DefinitionRetatrutide is an investigational weekly injection from Eli Lilly that activates three hormone receptors: GIP, GLP-1 and glucagon. It is not FDA-approved.

What it means

Retatrutide is called a triple agonist. Adding glucagon to the GIP and GLP-1 targets of tirzepatide may raise energy use and liver fat burning, on top of reducing appetite.

In a phase 2 trial published in NEJM in 2023, adults with obesity on the highest dose lost about 24% of body weight on average at 48 weeks, compared with about 2% on placebo. Lilly reported phase 3 TRIUMPH results in late 2025 and 2026, and said it planned to seek US approval in early 2027. Full peer-reviewed phase 3 data were still pending at our last review.

Until the FDA approves it, retatrutide is available only in clinical trials. The FDA has issued warning letters to companies selling retatrutide online, including products labeled "for research purposes." Those products have no FDA review of their contents, purity or dose.

Stomach side effects were the most common in trials, as with other drugs in this family.

Why it matters

Retatrutide is the most-searched pipeline drug, and much of what is sold under its name today is unapproved.

Related terms

Triple agonistGlucagon receptor agonistResearch peptides ("not for human use")TirzepatideRetatrutide

Sources

  1. Retatrutide phase 2 trial (NEJM, 2023)
  2. FDA: Concerns with unapproved GLP-1 drugs

Clinician review pending. Drafted from primary sources and waiting for sign-off by a licensed clinician (MD, DO or PharmD) before launch. Every number is checked against its source. Drug facts are re-checked quarterly, prices monthly and whenever a label changes. How we review · Report an error