FDA Peptide Categories: Category 1 vs Category 2 Explained
James MitchellMSc Biochemistry Timeline
FDA peptide compounding review — timeline
- 2023
Safety-risk signals
FDA flags several peptide-related bulk substances for safety and characterization concerns.
- 2025
Interim policy revised
FDA says newly nominated substances will no longer be placed into the interim Category 1/2/3 buckets.
- May 2026
503A list updated
FDA updates the 503A category PDF, including route-specific GHK-Cu language.
- Jul 2026
PCAC review
FDA schedules several peptide-related nominations for advisory committee discussion.
- After review
Final source check
Compounders and readers should rely on final FDA actions, not forecast labels.
What Are FDA Bulk-Substance Categories?
FDA’s Category 1, Category 2, and Category 3 labels are interim-policy categories for bulk drug substances nominated for compounding under sections 503A and 503B of the Federal Food, Drug, and Cosmetic Act. They are not a simple “legal vs illegal peptide” list, and they are not the same thing as controlled-substance scheduling.
The category can also differ by pathway. A substance may have a 503A signal, a 503B signal, a route-specific signal, or no current category in the latest FDA list.
Category 1: Under Evaluation
Category 1 means FDA has sufficient supporting information to evaluate the nominated bulk drug substance and the substance does not appear on another disqualifying list. FDA’s interim policy says the agency does not intend to take action against eligible 503A or 503B compounders for using Category 1 substances when the policy conditions are met.
That is different from a finding that the product is FDA-approved, safe, effective, or appropriate for personal use. It only describes an interim compounding-policy posture while FDA evaluates the nomination.
Category 2: Significant Safety-Risk Signal
Category 2 means FDA has sufficient information to evaluate the nomination but has identified significant safety risks relating to use of the substance in compounding pending further evaluation. Category 2 substances are not within the Category 1 enforcement-discretion policy, and FDA says it may consider action under general enforcement policies.
FDA’s current safety-risk page also discusses peptide-related substances that may no longer appear in the current Category 2 table because nominations were withdrawn or the substance is being handled through another review route. That is why route, date, and exact source page matter.
Category 3: Nominated Without Adequate Support
Category 3 means a nominated substance may be eligible for the relevant bulk-substance list, but the nomination lacks enough supporting information for FDA to evaluate it. These substances are not covered by the Category 1 interim policy.
As of FDA’s May 14, 2026 503A update, GHRP-2 and GHRP-6 appear in Category 3 rather than Category 2.
Peptide Examples to Watch
- BPC-157 and TB-500: FDA has identified safety-risk concerns and has scheduled BPC-157-related and TB-500-related substances for Pharmacy Compounding Advisory Committee discussion on July 23, 2026.
- MOTs-C, DSIP, Semax, and Epitalon: FDA has scheduled these peptide-related substances for July 2026 Pharmacy Compounding Advisory Committee discussion.
- GHK-Cu: FDA’s May 14, 2026 update added GHK-Cu, except for injectable routes of administration, back to Category 1; injectable GHK-Cu remains a separate safety-risk concern.
- AOD-9604, CJC-1295, Ipamorelin acetate, Melanotan II, Selank acetate, and Thymosin-alpha 1: FDA’s safety-risk page discusses these as peptide-related compounding risk signals.
What This Means for Readers
If a peptide appears in the FDA conversation, verify the exact current source before drawing conclusions:
- Check whether the substance is listed under 503A, 503B, both, or neither.
- Check whether the FDA source is the current category PDF, the safety-risk page, a PCAC meeting notice, a final rule, or a guidance page.
- Confirm whether the signal is route-specific, as with GHK-Cu.
- Confirm pharmacy and prescriber status directly with licensed professionals.
PeptideUnicorn does not prescribe, dispense, recommend personal use, or provide legal advice.
Primary Sources
- FDA 503A bulk drug substances page
- FDA 503A category PDF, updated May 14, 2026
- FDA safety risks associated with certain bulk drug substances
- FDA July 23-24, 2026 Pharmacy Compounding Advisory Committee notice