What are FDA Category 2 bulk drug substances?

They are raw active ingredients nominated for pharmacy compounding that FDA has flagged for significant safety risks. FDA has enough information to evaluate the nominations, but these ingredients do not receive the temporary enforcement policy available to Category 1 substances. Category 2 is not a finished-drug approval or a complete answer about an individual prescription.

How do FDA Categories 1, 2 and 3 differ?

Category 1 has enough supporting information for review and can receive a conditional temporary enforcement policy. Category 2 also has enough information for review, but FDA has identified significant safety risks. Category 3 lacks enough supporting information. The numbers describe different situations; they are not a ranking of danger or three steps toward approval.

Does leaving Category 2 mean a peptide is approved?

No. A substance can leave Category 2 because its nomination was withdrawn. That does not place it in Category 1, add it to the final 503A ingredient list or approve a finished medicine. FDA may continue reviewing the substance independently, and its published safety concerns can remain after withdrawal.

Which peptide remains in 503A Category 2?

Kisspeptin-10 is the peptide in the six-entry 503A Category 2 list in FDA’s PDF marked “Updated May 14, 2026,” checked on September 10, 2026. The separate 503B safety table includes other peptides. The section number matters, and the list is a dated snapshot rather than a permanent classification.

Can a provider prescribe a compounded medication during FDA review?

A licensed provider may consider a compounded formulation for an individual patient while FDA review continues. The clinical decision belongs with the patient and doctor; the pharmacy must separately satisfy applicable federal and state requirements for the ingredient and preparation. A prescription does not override those requirements or establish the preparation’s safety and effectiveness.

FDA Category 2 Bulk Drug Substances: What It Means

FDA Category 2 bulk drug substances are raw medicine ingredients that FDA has flagged for significant safety concerns while considering them for pharmacy compounding. Compounding means preparing a medication for a particular prescription. Category 2 describes FDA's approach to those ingredients; it does not approve a medicine or settle every question about a prescription.

FDA Category 2 bulk drug substances: the official meaning

The categories belong to an interim policy—a temporary approach while FDA completes ingredient reviews. They apply here to Section 503A, the federal framework for compounding for an identified patient.

FDA's January 2025 guidance separates nominated ingredients, meaning ingredients submitted for consideration, into three groups:

Category	What FDA has received or found	What it means for a pharmacy
1	Enough information to evaluate the nomination, without an identified significant safety risk requiring Category 2	FDA generally does not intend action over the pending ingredient-list requirement if its other conditions are met.
2	Enough information to evaluate, but significant safety risks identified	The Category 1 policy does not apply; FDA may take enforcement action.
3	Too little supporting information to evaluate	The Category 1 policy does not apply here either.

These numbers aren't stages a substance must pass through. Category 3 does not mean more dangerous than Category 2.

Why these categories exist

The Drug Quality and Security Act, enacted November 27, 2013, clarified the existing compounding framework. It followed the 2012 fungal meningitis outbreak, an infection affecting the membranes around the brain and spinal cord. A 2013 investigation in the New England Journal of Medicine traced infections to contaminated compounded steroid injections.

FDA then restarted work on its ingredient list. Reviewing hundreds of submissions and writing final rules took time. The interim categories let FDA describe its position during that work while limiting unnecessary interruptions to existing patient care.

Peptides—short chains of the building blocks of proteins—became a prominent example. FDA's document marked “Updated September 29, 2023”, preserved by the Alliance for Pharmacy Compounding, added BPC-157, injectable GHK-Cu and other substances to Category 2. Pharmacies could no longer rely on the Category 1 policy for those ingredients. A BPC-157 prescription required attention to the ingredient rules as well as the patient's needs.

What changed around the April and July reviews

FDA's meeting notice was filed April 15, 2026, and published April 16 as Federal Register document 2026-07361. It scheduled seven peptide reviews for July 23–24. FDA separately published a five-substance agenda for a meeting before the end of February 2027: LL-37, GHK-Cu, Dihexa acetate, Melanotan II and PEG-MGF.

Those 12 peptides appear in FDA's withdrawn-nomination table, rather than the active 503A Category 2 list. Withdrawal means the people who submitted the nominations took them back. It does not mean FDA withdrew its safety concerns.

As of September 10, 2026, the day this article was written, FDA's July 23–24 briefing introduction confirms that it proceeded with the seven reviews despite those withdrawals. Its meeting page, carrying “Updated Information (as of 7/14/2026),” posts the review materials but no minutes or vote tally. The Pharmacy Compounding Advisory Committee, or PCAC, gives outside expert advice; it does not make the final rule.

Promise's FDA peptide decision explainer follows that separate committee process.

How the term shows up in a prescription

A clinician weighs whether a formulation fits a patient. A pharmacist also checks whether the exact ingredient and preparation meet the applicable federal and state conditions. One decision does not replace the other.

A licensed provider may still prescribe a compounded formulation; that decision is between the patient and the doctor. A prescription does not override the pharmacy's ingredient requirements.

Tirzepatide helps explain another distinction. It is an ingredient in branded medicines, so its compounding questions do not depend solely on the peptide nomination categories. FDA's ingredient overview describes the different routes; all other compounding conditions still matter.

Through Promise, tirzepatide is dispensed as a compounded medication, which is different from an FDA-approved product: the formulation offered here is not FDA-approved.

Which Category 2 peptides remain?

As of September 10, 2026, the day this article was written, the current FDA nominations PDF reads “Updated May 14, 2026.” Its complete 503A Category 2 list is:

Cesium Chloride
Domperidone
Germanium Sesquioxide
Ibutamoren Mesylate
Kisspeptin-10
Quinacrine Hydrochloride for intrauterine administration

Kisspeptin-10 is the peptide remaining on that list. The last entry's restriction concerns administration into the uterus; the route is part of the listing, not an optional detail.

The separate 503B framework applies to FDA-registered outsourcing facilities, which can prepare supplies without an individual prescription first. FDA's safety page still places GHRP-2, GHRP-6 and ipamorelin acetate in 503B Category 2. A screenshot that leaves out “503A” or “503B” can give the wrong answer.

The mistakes people make with Category 2

Treating the category as a blanket ban. It is an enforcement-policy classification, not a stand-alone ruling about every possible prescription. Its practical consequence still matters: the pharmacy cannot rely on Category 1's temporary policy.

Reading removal as approval. Removal after a withdrawal does not place an ingredient in Category 1, finish the 503A rulemaking process or approve a finished medicine. BPC-157 remains not FDA-approved.

Assuming a new nomination buys temporary coverage. The January 2025 guidance says FDA does not intend to categorize substances newly nominated on or after January 7, 2025. Submitting paperwork does not automatically put an ingredient in Category 1.

Using a list position as a vial-quality check. In a 2024 Journal of Medical Internet Research study, three semaglutide vials bought without prescriptions contained about 29%–39% more drug than their labels stated. That small study tested those sellers' products, not prescribed BPC-157 or Promise's formulations. It illustrates why identifying the ingredient and verifying a supplied product are different tasks.

For a BPC-157 visit, the useful record includes the reviewing clinician, the dispensing pharmacy, the exact formulation and a contact for follow-up. A category number cannot supply those details.

The 503A bulks list is the ingredient list established through regulation; it is distinct from the temporary categories. The Semax FDA history follows one withdrawn nomination through review. The GHK-Cu FDA review shows why the way a medicine is given can change its category.

At Promise, a licensed provider reviews every request, and not everyone qualifies. The conversation concerns a particular person and prescription, with the ingredient's current status checked alongside that person's medical history.