Peptide glossary
FDA 503A bulk substances list
Also: 503A category 2 · FDA compounding list · bulk drug substances
The U.S. FDA's evaluation of substances pharmacies may compound; in 2023 it placed many research peptides in category 2, barring them from compounding.
Section 503A of the U.S. Federal Food, Drug, and Cosmetic Act allows licensed pharmacies to compound medicines from bulk substances that appear on an approved list or meet other criteria. Substances nominated for the list are evaluated by the FDA and sorted into categories. Category 1 substances may be used while evaluation continues; category 2 substances have been found to raise significant safety risks and may not be compounded.
In September 2023 the FDA placed a group of peptides in category 2, citing the absence of human safety data. The group included BPC-157, CJC-1295, ipamorelin, GHRP-2, GHRP-6, AOD-9604, MOTS-c, epithalon, kisspeptin, KPV, thymosin alpha-1, DSIP, melanotan II and GHK-Cu. Each affected profile records the determination under "Regulatory status".
The list is an American compounding rule and has no legal force in Canada, where Health Canada sets the regime. It is cited on this site because it is the most explicit regulatory statement anywhere about the human-safety evidence for these compounds, and because it changed how they are discussed.
Compounds where this term matters
- BPC-157 →Gastric pentadecapeptide
- CJC-1295 →GHRH analogue (with and without DAC)
- Ipamorelin →Growth hormone secretagogue (ghrelin receptor agonist)
- GHRP-2 →Growth hormone-releasing peptide
- GHRP-6 →Growth hormone-releasing peptide
- AOD-9604 →Modified growth hormone fragment
- MOTS-c →Mitochondrial-derived peptide
- Epithalon →Synthetic pineal tetrapeptide
More terms
Research & educational use only. Definitions are informational and not medical advice. Products are supplied for laboratory research and are not for human use.