Category 1 vs Category 2 peptides: what FDA’s 503A compounding lists mean

Category 1 vs Category 2 peptides refers to two of the three interim lists the US Food and Drug Administration (FDA) keeps for bulk ingredients nominated for pharmacy compounding under section 503A. Neither category is an FDA approval, and neither is an evidence rating. Category 1 substances are “under evaluation”, and FDA does not intend to act against pharmacies that compound them if other conditions are met. Category 2 substances “raise significant safety risks” and are outside that policy (FDA interim policy guidance, January 2025). On FDA’s May 14, 2026 list, the only peptides in Category 1 are GHK-Cu (non-injectable), vasoactive intestinal peptide, glutathione and alanyl-L-glutamine (FDA 503A categories list).

Item	Status
US FDA status	Categories are not approvals. They cover only bulk substances nominated for the 503A bulks list (FDA)
Compounding (503A/503B)	503A Category 1 peptides: GHK-Cu (non-injectable), VIP, glutathione, alanyl-L-glutamine. 503A Category 2 peptide: kisspeptin-10. 503B Category 2: GHRP-2, GHRP-6, ipamorelin (FDA)
BPC-157 and 15 others	Withdrawn from Category 2 by nominators; now in no category
WADA 2026	Category status has no bearing on sport. BPC-157, for example, is prohibited under S0 (USADA)
Strongest evidence	Regulatory documents only; a category is not an evidence grade
Human trials	Not applicable to the lists. FDA records “no human exposure data” for KPV, MOTs-C, PEG-MGF and TB-500
Last checked	2026-09-30

What changed (October 2026): FDA’s category list (May 14, 2026) and safety page (April 22, 2026) were re-read on 2026-10-26 and are unchanged; a dated table of category changes is added, and so are the 2024 votes on CJC-1295 and AOD-9604 and the reported outcome of the July 2026 votes.

What do Category 1, 2 and 3 mean?

The categories are an interim sorting of substances that people nominated for the 503A bulks list, the regulation that will eventually say which non-approved ingredients pharmacies may compound. FDA defines them on its 503A bulk drug substances page:

Category	FDA definition (short)	Effect
1 – Under evaluation	Nominated with enough information to evaluate; on no other list	FDA does not intend to act, if all conditions are met
2 – Safety risks	Enough information to evaluate, but FDA “has identified significant safety risks”	Outside the Category 1 policy
3 – Inadequate support	Nominated with insufficient information to evaluate	Outside the policy; can be renominated

FDA’s January 2025 interim policy guidance sets four conditions before its non-enforcement policy applies: the substance appears in Category 1; every manufacturer of it is FDA-registered; it comes with a valid certificate of analysis; and the compounding meets all other conditions of section 503A. A product that misses any condition “may violate the FD&C Act”, the guidance says.

Where the categories come from

Section 503A lets a licensed pharmacist or physician compound from a bulk ingredient only if it (1) meets a USP or NF monograph, (2) is a component of an FDA-approved drug, or (3) appears on the 503A bulks list created by regulation (FDA guidance). Dietary-supplement monographs do not count, the guidance adds.

Because the bulks list was taking years to build, FDA issued interim policies in 2016 and 2017 and sorted nominations into the three categories, meant to “avoid unnecessary disruption to patient treatment”. The January 2025 revision kept the policy for substances already in Category 1, but ended categorization of new nominations from January 7, 2025. FDA wrote that categorizing new nominations “would unnecessarily expose patients to the risks” of such products. It also noted that its bulks-list review is “far less rigorous and less comprehensive” than a new drug review.

The categories are temporary. A substance leaves them when a final rule places it on the bulks list or rejects it, or when FDA moves it on safety grounds. Adding a substance requires advice from the advisory committee, consultation with USP, a proposed rule, public comment and a final rule.

Which peptides are in Category 1?

FDA’s categories list updated May 14, 2026 names 49 Category 1 entries. Most are vitamins, botanicals and small molecules. Four are peptides or short amino-acid chains:

Substance	What it is	Note
GHK-Cu (except injectable routes)	Copper-bound tripeptide	Removed April 22, 2026, re-added May 14, 2026 for non-injectable routes only
Vasoactive intestinal peptide (VIP)	28-amino-acid neuropeptide (Iwasaki 2019)	Category 1 as a bulk substance
Glutathione	Tripeptide γ-glutamyl-cysteinyl-glycine (Lu 2009)	Category 1 as a bulk substance
Alanyl-L-glutamine	Dipeptide	Category 1 as a bulk substance

The GHK-Cu entry is split by route. FDA’s list explains that one nominator withdrew only the injectable nomination, so “GHK-Cu (except for injectable routes of administration)” went back into Category 1. Injectable GHK-Cu is listed as previously in Category 2 and withdrawn. FDA says it intends to consult its Pharmacy Compounding Advisory Committee (PCAC) on GHK-Cu before the end of February 2027.

Which peptides are in Category 2?

FDA’s Category 2 safety page (current as of April 22, 2026) keeps these peptides and related secretagogues in Category 2. FDA placed each on September 29, 2023, except where noted:

Substance	List	FDA-stated risks
Kisspeptin-10	503A	Immunogenicity, peptide impurities, insufficient safety data
GHRP-2	503B	Immunogenicity, aggregation, unnatural amino acids
GHRP-6	503B	Immunogenicity, cortisol effects, lower insulin sensitivity
Ipamorelin acetate	503B	Immunogenicity, aggregation, serious adverse events
Ibutamoren mesylate (MK-677)	503A; 503B (Dec 29, 2022)	Possible congestive heart failure

These risk statements are FDA assessments, not trial results. Immunogenicity means the body may make antibodies against the peptide. Impurities are related peptide by-products left over from manufacture.

Category 3 peptides

The 503A Category 3 list (nominated without adequate support) includes GHRP-2, GHRP-6, mechano growth factor (MGF), cibinetide (ARA-290), thymulin acetate, human secretin and L-carnosine (FDA list). Category 3 substances are outside the non-enforcement policy. Since January 2025, a renomination leads to evaluation for the bulks list rather than a new category.

Peptides removed from Category 2: in no category

Sixteen substances appear on FDA’s safety page as “previously in Category 2”, withdrawn by their nominators: AOD-9604, BPC-157, cathelicidin LL-37, CJC-1295, dihexa acetate, emideltide (DSIP), epitalon, GHK-Cu (injectable), KPV, PEG-MGF, Melanotan II, MOTs-C, selank, semax, thymosin alpha-1 and TB-500. For several, FDA’s summary still lists concerns such as “no human exposure data” (KPV, MOTs-C, PEG-MGF, TB-500) or reported melanoma, encephalopathy and priapism (Melanotan II).

A withdrawal does not place a substance in Category 1. The interim guidance covers only Category 1 substances. It says a withdrawal does “not reflect a determination by FDA” on the nomination, and that FDA may keep evaluating the substance anyway.

FDA did keep evaluating. Its April 16, 2026 Federal Register notice scheduled a PCAC meeting on July 23–24, 2026 for seven of these peptides:

Peptide	Use FDA reviewed	FDA’s proposal
BPC-157	Ulcerative colitis	Do not include
KPV	Wound healing, inflammatory conditions	Do not include
TB-500	Wound healing	Do not include
MOTs-C	Obesity, osteoporosis	Do not include
Emideltide (DSIP)	Opioid withdrawal, insomnia, narcolepsy	Do not include
Semax	Cerebral ischemia, migraine, trigeminal neuralgia	Do not include
Epitalon	Insomnia	Do not include

The proposals come from FDA’s briefing introduction, which applies them to both the free-base and acetate forms of each peptide. It states that every nomination had been withdrawn, but “FDA is electing to proceed” with the review. The briefing adds that FDA “does not intend to issue a final determination” until the committee’s input has been considered. The committee advises and FDA decides. Trade press reported that the committee voted for listing six of the seven, all but emideltide; for BPC-157 the reported count was 8 yes, 6 no and 1 abstention (RAPS, 2026-07-23). When checked on 2026-10-26, the meeting page listed briefings, presentations and a roster, but no minutes or vote record, and the Federal Register showed no proposed rule adding any of the seven to the bulks list.

Two of the withdrawn peptides were reviewed earlier. On 2024-12-04 the committee voted against listing CJC-1295 (0 yes and 13 no for most forms, 1 yes and 12 no for the acetate) and AOD-9604 (0 yes, 12 no) (PCAC minutes).

Category changes by date

The main changes for peptides, with the FDA record for each:

Date	Change	Source
2022-12-29	Ibutamoren mesylate placed in 503B Category 2	FDA safety page
2023-09-29	Placement date FDA gives for those still in Category 2: kisspeptin-10 and ibutamoren (503A); GHRP-2, GHRP-6 and ipamorelin acetate (503B)	FDA safety page
2024-12-04	Advisory committee votes against listing CJC-1295 and AOD-9604	PCAC minutes
2025-01-07	FDA stops placing new nominations in any category	FDA 503A page
2026-04-22	Safety page lists 16 substances, BPC-157 and TB-500 among them, as withdrawn from Category 2; GHK-Cu removed from Category 1	FDA safety page; FDA list
2026-05-14	Category list updated: GHK-Cu back in Category 1 for non-injectable routes	FDA list
2026-07-23	Advisory committee reviews seven withdrawn peptides; FDA had proposed against all seven	FDA briefing
By end of February 2027	FDA intends to consult the committee on GHK-Cu	FDA list

Category 1 vs Category 2 peptides vs approval: a comparison

Status	What it allows	Peptide examples
FDA-approved drug	Marketing for the labeled use	Semaglutide, tirzepatide (FDA)
503A bulks list (final rule)	503A compounding under the statute	None of the peptides above
503A Category 1	FDA enforcement discretion only, with conditions	GHK-Cu (non-injectable), VIP, glutathione
503A Category 2	Outside the policy; safety risks identified	Kisspeptin-10
No category	Outside the policy	BPC-157, TB-500, CJC-1295

How 503B categories differ

Outsourcing facilities compound under section 503B. They have a separate bulks list, which uses a “clinical need” standard, and separate categories with the same three meanings (FDA 503B page). The same January 7, 2025 cutoff for new categorization applies. A peptide can therefore hold different statuses: GHRP-2 is in 503A Category 3 and 503B Category 2.

Safety and unregulated products

Category status says nothing about whether a peptide works. FDA’s Category 2 summaries point to recurring risks for injectable peptides: immunogenicity, aggregation, impurities and missing human safety data (FDA). These are regulatory assessments, not measured rates of harm.

Products sold outside pharmacies as “research use only” fall outside every category. In an August 24, 2026 warning letter about products including semaglutide, retatrutide, SS-31, PT-141 and tesamorelin, FDA found that such labels did not stop the products from being unapproved drugs for human use. Investigational agents such as retatrutide cannot be compounded under federal law at all (FDA).

Category status and sport

Anti-doping rules do not follow FDA’s compounding categories. USADA states that BPC-157 is prohibited under S0 (non-approved substances) of the WADA list. A pharmacy prescription does not change that. The WADA banned peptides page covers other peptides.