Retatrutide: FDA and compounding status

Quick answer

Retatrutide is investigational and not an FDA-approved drug and is not on FDA's 503A Bulks List. Section 503A records it as "Not nominated" (May 14, 2026) and section 503B as "Not nominated" (March 21, 2025). No PCAC recommendation is on file and the committee is advisory; verified September 16, 2026.

By Peptides.NYC Editorial TeamPublished September 16, 2026

Verified against FDA's bulk substances page on September 16, 2026. Every field below links the document it came from.

Current status

Retatrutide

FDA approval

Investigational

Retatrutide (LY3437943) is an investigational agent in phase 3 trials sponsored by Eli Lilly and Company. FDA has told sellers in writing that products offered as "Retatrutide" are unapproved new drugs under section 505(a) of the FD&C Act.

Sources

ClinicalTrials.gov, NCT06662383: "A Phase 3, Randomized, Double-Blind Study to Evaluate the Efficacy and Safety of Retatrutide Compared to Tirzepatide in Adults Who Have Obesity" (Eli Lilly and Company; active, not recruiting) (U.S. National Library of Medicine, retrieved 2026-09-16)
FDA warning letter to Gram Peptides (MARCS-CMS 721806), March 31, 2026: "Retatrutide" and "Tirzepatide" products are unapproved new drugs under section 505(a) (U.S. Food and Drug Administration, retrieved 2026-09-16)

Section 503A

Not nominated

As stated on the cited document, dated May 14, 2026.

The substance appears in none of the categories on that nomination document, as of the document's own date.

Appears in none of the three categories on FDA's section 503A nomination document as of that document's own date.

Sources

FDA, Bulk Drug Substances Nominated for Use in Compounding Under Section 503A of the FD&C Act, updated May 14, 2026 (U.S. Food and Drug Administration, retrieved 2026-09-16)

Section 503B

Not nominated

As stated on the cited document, dated March 21, 2025.

The substance appears in none of the categories on that nomination document, as of the document's own date.

Appears in none of the three categories on FDA's section 503B nomination document as of that document's own date.

Sources

FDA, Bulk Drug Substances Nominated for Use in Compounding Under Section 503B of the FD&C Act, updated March 21, 2025 (U.S. Food and Drug Administration, retrieved 2026-09-16)

Verified against FDA's bulk substances page on September 16, 2026.

Timeline

Every dated event on file for Retatrutide, newest first, with the document it came from.

March 31, 2026Status change
FDA issued a warning letter to Gram Peptides stating that the "Retatrutide" and "Tirzepatide" products it offered for sale are unapproved new drugs under section 505(a) of the FD&C Act.
Sources
- FDA warning letter to Gram Peptides (MARCS-CMS 721806), March 31, 2026: "Retatrutide" and "Tirzepatide" products are unapproved new drugs under section 505(a) (U.S. Food and Drug Administration, retrieved 2026-09-16)

Related guides

Frequently asked questions

Is Retatrutide legal to compound?

On FDA's section 503A list, Retatrutide is recorded as "Not nominated" as of May 14, 2026. On FDA's section 503B list, Retatrutide is recorded as "Not nominated" as of March 21, 2025. Retatrutide is not on FDA's 503A Bulks List: that list is established by notice-and-comment rulemaking, and none of the categories above is inclusion on it. Compounding is governed by federal and state law together, and a pharmacy or outsourcing facility answers to both. This page reports what FDA has published; it is not legal or medical advice.

Was Retatrutide reviewed by PCAC?

This tracker cites no Pharmacy Compounding Advisory Committee record for Retatrutide. PCAC's role is advisory: FDA must still complete notice-and-comment rulemaking before anything is added to the 503A Bulks List.

Is Retatrutide FDA-approved?

Disclaimer: This page is a record of what regulators have published about Retatrutide. It is for educational purposes only, it is not medical or legal advice, and it is not a recommendation to use or compound any substance. Regulatory status changes; check the linked primary sources and consult your healthcare provider.