Retatrutide · FDA Classification

Is Retatrutide a Biologic or a Drug?

Retatrutide is an investigational peptide medicine. FDA initially designated it a drug rather than a biologic, but a federal court reopened part of that decision. Its final U.S. biologic classification remains unresolved.

LiveNow Longevity · Updated September 25, 2026

Drug and biologic are not opposites

“Peptide” describes the molecule. “Biologic” describes a regulatory category. FDA says biological products also meet the legal definition of drugs, so the question is which approval pathway would apply to retatrutide, not whether it is a medicine at all.

Under FDA's protein rule, a protein must contain more than 40 alpha amino acids. The court upheld FDA's conclusion that retatrutide does not qualify as a protein under that rule. It did not decide that retatrutide can never be a biologic: it returned the separate “analogous to a protein” question to FDA for reconsideration.

What happened, and what is still open

March 18, 2024: FDA issued a letter designating retatrutide a drug rather than a biological product.
October 3, 2025: An amended federal court order upheld the “not a protein” finding, but vacated FDA's separate reasoning on the “analogous product” route and sent that issue back to the agency.
July 23, 2026: Lilly said it planned to submit a Biologics License Application in the first quarter of 2027. The plan does not announce an FDA decision or an approval date.
September 24, 2026: The Seventh Circuit heard oral argument in Lilly's appeal, No. 26-1301. The hearing did not change retatrutide's FDA approval or compounding status.

The distinction: The court did not declare retatrutide a biologic. FDA must still address the issue returned to it, and any application would require its own review.

Does this change access today?

No. Retatrutide is not FDA-approved. FDA also states that retatrutide cannot be used in compounding under federal law. Neither a trial result, a planned application nor this classification dispute creates a retail prescription option.

LiveNow does not offer retatrutide treatment or a retatrutide waitlist. For its current status, read our retatrutide FDA-status guide. For presently available care, see medical weight-management information; an evaluation does not guarantee any prescription.

Common questions

Is retatrutide a biologic?

Its U.S. biologic classification is unresolved. FDA designated it a drug rather than a biologic in 2024. A federal court upheld FDA's finding that it is not a protein under the agency's rule, but ordered FDA to reconsider its separate decision on whether retatrutide is analogous to a protein.

Is retatrutide a drug?

Retatrutide is an investigational peptide medicine. FDA initially designated it a drug rather than a biologic. The terms are not opposites in every context: FDA explains that biological products also meet the legal definition of drugs.

Does Lilly's planned biologics application mean retatrutide is approved?

No. Lilly said in July 2026 that it planned to submit a Biologics License Application in the first quarter of 2027. A planned application is neither an FDA classification decision nor approval to market retatrutide.

Can retatrutide be compounded while the classification is disputed?

No. FDA says retatrutide cannot be used in compounding under federal law. The classification dispute does not make it an approved or legally compoundable treatment.

When will the FDA settle the question?

There is no confirmed date for a final classification or approval decision. Lilly's planned 2027 application date is a company forecast, not an FDA decision date.

Public regulatory sources checked September 25, 2026. This page is educational information, not medical or legal advice.

Primary sources

The court order, FDA guidance and Lilly statement support the dated answer above. Recheck these sources when FDA acts on the classification or an application.