Peptides like BPC-157, KPV and TB-500 keep coming up in the same regulatory sentence: "under FDA review for the 503A Bulks List." What that list actually is, who decides what goes on it, and what changed in the process in 2025 is worth understanding on its own, separate from any single peptide's status.
The Drug Quality and Security Act (DQSA) of 2013 established the modern framework for pharmacy compounding, splitting it into two categories: 503A, traditional state-licensed compounding pharmacies that prepare drugs for individually identified patients, and 503B, FDA-registered outsourcing facilities that can compound in larger batches without a patient-specific prescription. Both categories are restricted in which non-FDA-approved active ingredients — "bulk drug substances" — they may use, and the FDA maintains separate lists for each category. A substance has to appear on the relevant list before compounders can lawfully use it as an active ingredient for that category.
Per FDA guidance, any interested person can nominate a bulk drug substance for the 503A list. The FDA published a Federal Register notice on December 4, 2013 formally inviting nominations, and the agency continues to accept them on an ongoing basis. A nomination isn't a one-line request — the FDA guidance describes what supporting information a nomination should include, since the agency's review depends on the substance-specific data submitted alongside it.
Once nominated, the FDA assesses a bulk drug substance against four statutory criteria:
This is the same four-part framework applied to every peptide reviewed at the FDA's Pharmacy Compounding Advisory Committee (PCAC) meetings, including the July 2026 session that covered BPC-157, TB-500, KPV, MOTS-c, Semax and Epitalon.
The Pharmacy Compounding Advisory Committee (PCAC) is the FDA's standing advisory body for these decisions. Its review process combines PCAC evaluation, consultation with the United States Pharmacopeia (USP), and public comment collected through Federal Register notices, feeding into the FDA's own determination of whether a substance meets the statutory criteria. Committee recommendations are advisory; the agency retains final decision-making authority, and the FDA's own briefing documents — such as the one prepared for the July 2026 PCAC meeting — can diverge from, or run ahead of, the committee's eventual vote.
This is the detail with the most direct, practical relevance for research peptides. Historically, the FDA sorted newly nominated substances into interim categories that allowed some compounding to continue while a nomination was pending review. Effective January 7, 2025, the FDA discontinued that interim-category approach for newly nominated substances: pharmacies may no longer compound with a newly nominated bulk drug substance unless and until the FDA completes its full review and adds it to the final list. In practice, that means a "pending 503A review" status is no longer a green light to compound with a peptide — it is closer to a hold, until and unless the FDA issues a final, affirmative listing decision.
For the specific July 2026 PCAC meeting and its agenda, see FDA Reviews BPC-157, TB-500, KPV and More Peptides at July 2026 Compounding Meeting.