How Generic GLP-1 Drugs Get Approved: The ANDA Pathway for Peptides

Discussions of cheaper copies of Ozempic or Zepbound often assume they will be biosimilars, the pathway built for large biologic medicines. Under U.S. rules, the GLP-1 drugs on the market today sit on the other side of that line. Liraglutide, semaglutide, and tirzepatide products are approved as drugs under new drug applications (NDAs), so copies are reviewed as generics through abbreviated new drug applications (ANDAs).

In a final rule effective March 23, 2020, the FDA defined a 'protein', and therefore a biological product, as an alpha amino acid polymer with a specific defined sequence greater than 40 amino acids. According to the FDA, polymers of 40 or fewer amino acids are peptides and were not affected by the transition that moved protein products such as insulin from NDAs to biologics licenses on that date. The FDA's July 2026 guidance announcement lists Victoza, Saxenda, Ozempic, Wegovy, Mounjaro, and Zepbound by their NDA numbers.

An ANDA does not repeat the brand's large clinical trials. The applicant generally has to show that its product is the same as the reference drug in active ingredient, strength, dosage form, and route, and is therapeutically equivalent. For peptides, proving the active ingredient is the same is harder than for a simple tablet, which is what the FDA's product-specific guidances (PSGs) address.

On July 28, 2026, the FDA published 17 revised draft PSGs for peptide products, including the six GLP-1 brands above. The agency said they update its recommendations in five areas: submitting recombinant, synthetic, or semi-synthetic peptides as ANDAs, innate immune response testing, impurity thresholds, higher order structure, and biological activity. The same day it withdrew its May 2021 guidance on synthetic peptide ANDAs, saying it no longer reflects current scientific thinking and that a revision is planned.

The pathway is already in use. The FDA approved the first generic referencing Victoza, from Hikma, on December 23, 2024, about a month after it approved the first generic referencing Byetta (exenatide). Teva announced FDA approval and launch of a generic version of Saxenda on August 28, 2025, which the company described as the first generic GLP-1 indicated for weight loss.

The revised PSGs are drafts open to public comment, not approvals, and patents and regulatory exclusivity still largely decide when a generic semaglutide or tirzepatide can launch in the U.S. A practical check for anyone who sees a product marketed as 'generic Ozempic' or 'generic Zepbound': an FDA-approved generic has an application number that can be looked up in the FDA's Drugs@FDA database, while compounded or research-labeled products have no such approval.