The Peptide Library

Peptides are short chains of amino acids — typically between 2 and 50. Your body produces thousands of them naturally. They act as signaling molecules, telling cells what to do: repair tissue, regulate appetite, modulate immune response, release growth hormone. The biology isn't new. The ability to use specific peptides therapeutically is what's changed.

Compounded peptides are prepared by state-licensed compounding pharmacies under a prescription from a licensed clinician. The federal framework that governs this has two parts — 503A for patient-specific prescriptions and 503B for larger-batch outsourcing facilities. PepScribe works exclusively with licensed 503A pharmacies in the USA. Compounded medications are not FDA-approved, but they are legally prepared under a regulatory framework that has allowed pharmacies to compound custom medications for decades.

The FDA classifies bulk drug substances used in compounding into categories. Category 1 substances can be compounded today. Category 2 substances are under review and currently cannot be legally compounded. When the FDA changes a peptide's classification, the legal landscape shifts — and so does what your clinician can prescribe.