# FDA tells Lilly retatrutide is a drug, not a biologic

> FDA's Oct 2, 2026 letter says retatrutide is a drug. Lilly's appeal is pending and it plans to file by Q1 2027. Retatrutide is not FDA approved.

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- Last updated: November 5, 2026
- Publisher: Living+

Published November 5, 2026.

On October 2, 2026, FDA told Eli Lilly again that [retatrutide](/peptides/retatrutide/) is a drug, not a biologic [1]. FDA's rule treats a chain of more than 40 alpha amino acids as a protein, and FDA counts 39 in retatrutide [1]. Retatrutide is not FDA approved [2].

## Where the case stands

The question is before the U.S. Court of Appeals for the Seventh Circuit, where oral argument was held on September 24, 2026 [3]. We found no ruling as of November 5, 2026. In an October 8 filing, Lilly said it plans to file its application no later than the first quarter of 2027 and needs to know which pathway to use [4].

## Other recent news

On October 28, 2026, Lilly reported topline phase 3 results comparing retatrutide with Ozempic 2 mg in adults with type 2 diabetes [5]. These results have not yet been peer reviewed [5]. FDA says retatrutide cannot be used in compounding under federal law [2].

## Sources

1. [FDA: Letter to Eli Lilly on retatrutide, filed in 7th Cir. No. 26-1301 (Oct 2, 2026)](https://storage.courtlistener.com/recap/gov.uscourts.ca7.55916/gov.uscourts.ca7.55916.46.2.pdf)
2. [FDA: Concerns with unapproved GLP-1 drugs used for weight loss](https://www.fda.gov/drugs/drug-alerts-and-statements/fdas-concerns-unapproved-glp-1-drugs-used-weight-loss)
3. [U.S. Department of Justice: Supplemental letter, 7th Cir. No. 26-1301 (Oct 8, 2026)](https://storage.courtlistener.com/recap/gov.uscourts.ca7.55916/gov.uscourts.ca7.55916.46.1.pdf)
4. [Eli Lilly: Supplemental brief, 7th Cir. No. 26-1301 (Oct 8, 2026)](https://storage.courtlistener.com/recap/gov.uscourts.ca7.55916/gov.uscourts.ca7.55916.47.0.pdf)
5. [Lilly: TRANSCEND-T2D-2 topline results (Oct 28, 2026)](https://investor.lilly.com/news-releases/news-release-details/lillys-retatrutide-delivered-greater-a1c-reduction-and-more)

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