Buying and sourcing

The FDA compounding lists and peptides: what changed in 2023 and after

This page describes a United States regulatory record as published by the FDA. It is not legal advice, it does not describe the law in any other country, and it makes no claim about whether any substance is safe or effective.

What the lists are for

Sections 503A and 503B of the Federal Food, Drug, and Cosmetic Act set the conditions under which compounded drugs are exempt from certain requirements — 503A for state-licensed pharmacies and physicians, 503B for registered outsourcing facilities. One condition concerns the bulk drug substance used. A substance qualifies if it is the subject of an applicable monograph, is a component of an approved drug, or appears on a list the FDA develops.²³

The FDA solicited nominations for that 503A list in 2015 and issued a final regulation in February 2019 placing six substances on it and declining to place four others. Evaluating the remaining nominations takes years, so the agency published an interim policy describing when it does not intend to take action against a compounder in the meantime.⁵⁷⁴

The three categories, in the FDA's own terms

• Category 1 — substances that may be eligible for the 503A bulks list, nominated with sufficient supporting information for FDA to evaluate them, and not appearing on any other list. FDA does not intend to take action against a compounder using these, provided the conditions in the guidance are met.
• Category 2 — substances nominated with sufficient information to evaluate, for which FDA has identified significant safety risks relating to their use in compounding pending further evaluation. FDA does not extend the category 1 policy to them and would consider action under its general enforcement policies.
• Category 3 — substances that may be eligible but were nominated with insufficient supporting information for FDA to evaluate. They are not eligible for the category 1 policy, and can be re-nominated with adequate information.²⁴

What happened on 29 September 2023

That date appears against most of the peptide entries currently in category 2. The peptides and peptide-adjacent substances carrying it are:¹

• Growth hormone releasing peptide-2 (GHRP-2), scoped to certain routes of administration — 503B category 2.
• Growth hormone releasing peptide-6 (GHRP-6) — 503B category 2.
• Ipamorelin acetate — 503B category 2.
• Kisspeptin-10 — 503A category 2.
• Ibutamoren mesylate — 503A category 2 on that date; it had already been placed in 503B category 2 on 29 December 2022.¹

The reasons the FDA published are specific and mostly of one shape. For GHRP-2 it cites potential immunogenicity from aggregation and peptide-related impurities, the presence of an unnatural amino acid complicating characterisation, and awareness of reports of serious adverse events without established causality. For GHRP-6 it cites limited safety information and concerns including effects on cortisol and blood glucose. For kisspeptin-10 it states it has no, or only limited, safety-related information for the proposed routes and therefore lacks sufficient information to know whether the drug would cause harm.¹

Ibutamoren is the exception worth noting, because the FDA's stated reason is a result rather than a gap: it refers to a randomised, placebo-controlled trial in patients recovering from hip fracture that was terminated early due to a potential safety signal of congestive heart failure.¹

The withdrawn list, which is where most peptides now sit

The FDA maintains a second table on the same page for substances previously in category 2 whose nominations were withdrawn by the nominators. It is longer than the active table and it is where most of the compounds this site tracks appear:¹

• BPC-157
• Thymosin beta-4, fragment (LKKTETQ), also known as TB-500
• CJC-1295
• Ipamorelin acetate (also still in the 503B table)
• AOD-9604
• Epitalon
• Semax (heptapeptide)
• Selank acetate (TP-7)
• Emideltide (DSIP)
• Dihexa acetate
• KPV
• MOTs-C
• Melanotan II
• GHK-Cu, scoped to certain routes of administration
• Mechano growth factor pegylated (PEG-MGF)
• Thymosin-alpha 1 (Ta1)
• Cathelicidin LL-37¹

Withdrawal is a procedural act by whoever nominated the substance. It removes the entry from category 2. It does not place the substance on the 503A bulks list, and a substance that is not on that list, not the subject of an applicable monograph, and not a component of an approved drug does not meet the 503A condition in the first place. Coming off category 2 is therefore not the same as becoming available, and reports that describe it as a reversal are describing something that did not happen.¹²

The sentence the FDA keeps writing

Across the withdrawn list the agency's stated reasons converge on one formulation. For dihexa acetate and for KPV it says it has not identified any human exposure data at all for drug products containing the substance. For emideltide, epitalon, Semax and BPC-157 it says it lacks sufficient information to know whether the drug would cause harm if administered to humans. For thymosin beta-4 fragment it says it has not identified any human exposure data and lacks important information regarding any safety issues.¹

This is the same gap this site measures from the registry, described by a regulator working from its own review. Two independent lines of evidence — a count of ClinicalTrials.gov records and the FDA's assessment of nomination dossiers — reach the same place on the same compounds.¹⁶

What changed after 2023

Two things. The withdrawals moved a large group of peptides out of the active category 2 table and onto the withdrawn list, without changing their eligibility. And the FDA issued guidance revising the interim policy's application, stating that it does not intend to place bulk drug substances nominated on or after 7 January 2025 into these categories at all. Substances already in category 1 may remain within the interim enforcement policy until the agency decides on their inclusion in the list, or removes them.²

The practical effect for a reader is that the category tables are a snapshot of an evaluation process, not a stable classification system. The FDA page carries its own currency date, and that date is the only thing that makes any statement about the lists checkable.¹²