If you've been following the peptide space in 2025-2026, you've likely encountered references to "Category 1" and "Category 2" peptides. These terms come up in clinic marketing, telehealth consultations, online forums, and news coverage of regulatory changes -- but what they actually mean, and why they matter for your ability to access peptide therapies legally, is often glossed over or misrepresented.
This article breaks down the FDA's classification system for bulk drug substances used in compounding, explains what each category means in practice, and covers why reclassification has become one of the most important topics in the peptide world.
- The FDA uses a three-category system to determine which bulk drug substances can be used by compounding pharmacies.
- Category 1 substances can be compounded with a valid prescription. Category 2 substances cannot.
- Many popular peptides -- including BPC-157, TB-500, and CJC-1295 -- are currently Category 2, meaning they are restricted from compounding.
- A potential reclassification of ~14 peptides from Category 2 to Category 1 has been signaled but not yet formalized.
Quick facts
- Category 1
- Can be compounded with a valid prescription
- Category 2
- Restricted — cannot be compounded
- Category 3
- Under active evaluation by the FDA
- Governing law
- FDCA Sections 503A and 503B
What the categories mean
The FDA maintains lists of bulk drug substances -- the raw ingredients that compounding pharmacies use to prepare medications -- organized into three categories. These categories determine whether a substance can legally be used in compounding.[1]
Category 1: Can be compounded. These are bulk drug substances that the FDA has evaluated and deemed appropriate for use in compounding by licensed pharmacies. If a substance is on the Category 1 list, a licensed prescriber (physician, nurse practitioner, or other qualified provider) can write a prescription for it, and a compounding pharmacy operating under Section 503A or 503B of the Federal Food, Drug, and Cosmetic Act can legally prepare it.[3] Category 1 does not mean FDA-approved -- it means the substance has cleared the bar for compounding use.
Category 2: Cannot be compounded. These are substances that the FDA has determined present "demonstrable difficulties" for compounding.[2] The reasons vary: some substances were flagged for safety concerns, others for the complexity of formulating them reliably, and others because the FDA concluded there was insufficient safety or efficacy data to support their use in compounded preparations. When a substance is on Category 2, compounding pharmacies are prohibited from using it -- full stop.
Category 3: Under evaluation. These are substances that have been nominated for inclusion on the compounding lists but haven't received a final determination. The FDA is still reviewing the available evidence. A Category 3 substance could eventually move to Category 1 or Category 2 depending on the outcome of that review.[5]
How substances get categorized
The process begins with nominations. Under the framework established by the FDCA, anyone -- a physician, a compounding pharmacy, a patient advocacy group, or a pharmaceutical company -- can nominate a bulk drug substance for evaluation and potential inclusion on the 503A or 503B compounding lists.[4]
When a nomination is submitted, the FDA evaluates the substance against several criteria:[5]
- Physical and chemical characterization: Is the substance well-defined? Can its identity and purity be reliably verified?
- Safety information: What does the available evidence say about the substance's safety profile? This includes published literature, adverse event reports, and any available clinical data.
- Historical use in compounding: Has the substance been used in compounding practice, and if so, what is the track record?
- Available literature: What peer-reviewed research exists on the substance's pharmacology, toxicology, and therapeutic potential?
The FDA reviews these factors and places the substance into one of the three categories. This process is not instantaneous -- it can take months or even years, and the FDA has faced criticism for the pace at which it processes nominations.[6]
It's worth noting that the evaluation criteria are not purely scientific. The FDA also considers whether a commercially available, FDA-approved version of the substance exists (or a closely related alternative), which can influence whether compounding is deemed necessary.
Which peptides are in each category
Here's a snapshot of where notable peptides stand in the FDA's category system as of March 2026:
| Peptide | Current Category | Notes |
|---|---|---|
| Thymosin Alpha-1 | Category 1 | Already compoundable |
| Sermorelin | Category 1 | Already compoundable |
| GHK-Cu | Category 1 | Already compoundable |
| BPC-157 | Category 2 | Restricted; potentially reclassifying |
| TB-500 | Category 2 | Restricted; potentially reclassifying |
| CJC-1295 | Category 2 | Restricted; potentially reclassifying |
| Ipamorelin | Category 2 | Restricted; potentially reclassifying |
| AOD-9604 | Category 2 | Restricted; potentially reclassifying |
| Kisspeptin | Category 2 | Restricted |
| Selank | Category 2 | Restricted |
This is not an exhaustive list. The FDA's full Category 1 and Category 2 lists contain dozens of substances beyond peptides, including various small molecules and other compounding ingredients.[1][2]
The reclassification question
The category system became front-page news in the peptide world on February 27, 2026, when HHS Secretary Robert F. Kennedy Jr. announced that his department would direct the FDA to begin reclassifying approximately 14 peptides from Category 2 to Category 1. If formalized, this would be the single largest expansion of legal peptide access through compounding in the history of the current system.
The signal was significant. But as of March 2026, it remains just that -- a signal. No formal FDA rulemaking has been published. No Federal Register notice has appeared. The gap between an HHS political statement and an actual FDA regulatory action is real, and it matters.
For a reclassification to take legal effect, the FDA would typically need to conduct its own internal review, publish a proposed rule, accept public comment, and issue a final determination. That process takes time -- and the FDA's career regulatory staff have historically maintained a degree of independence from political direction.[6]
For the full story on the Kennedy announcement, including which specific peptides are expected to be affected and the timeline for formal action, see our detailed coverage: Kennedy Peptide Reclassification: What Changed and What It Means.
What this means for you
The category system has a direct, practical impact on whether you can access a given peptide through legitimate channels.
If a peptide is Category 1, a licensed prescriber can evaluate whether it's appropriate for you and write a prescription. A compounding pharmacy operating under Section 503A or 503B can then prepare it. This is the legal, regulated pathway -- and it comes with quality controls including sterility testing, potency verification, and proper labeling.[3]
If a peptide is Category 2, it is not available through legitimate compounding pharmacies. Any source offering a Category 2 peptide is operating outside the regulated system -- whether that's a gray-market research chemical vendor, an overseas supplier, or an unlicensed compounder. These sources carry documented risks including contamination, incorrect dosing, and wrong-molecule substitution.
If a peptide is Category 3, its status is pending. It may become available through compounding in the future, but for now, it exists in regulatory limbo.
The most important thing you can do is stay informed. Reclassification proceedings are ongoing, and the landscape could shift meaningfully in the coming months. Work with a licensed healthcare provider who understands the regulatory environment, and verify claims about peptide legality against the FDA's official category lists rather than relying on marketing materials or social media.
References
- [1]U.S. Food and Drug Administration. “Bulk Drug Substances That Can Be Used in Compounding Under Section 503A and 503B: Category 1 List.” FDA.gov. 2024. LinkRegulatory document
- [2]U.S. Food and Drug Administration. “Bulk Drug Substances That Can Be Used in Compounding Under Section 503A and 503B: Category 2 List.” FDA.gov. 2023. LinkRegulatory document
- [3]U.S. Food and Drug Administration. “Compounding Laws and Policies: Section 503A and 503B of the Federal Food, Drug, and Cosmetic Act.” FDA.gov. 2024. LinkRegulatory guidance
- [4]U.S. Food and Drug Administration. “Bulk Drug Substance Nominations: How to Submit a Nomination for Evaluation.” FDA.gov. 2023. LinkRegulatory guidance
- [5]U.S. Food and Drug Administration. “Evaluation of Bulk Drug Substances Nominated for Use in Compounding: Criteria and Process.” FDA.gov. 2024. LinkRegulatory document
- [6]McGuire MF, Brewer JR. “Regulatory Landscape for Compounded Peptide Therapies in the United States: A Review.” Therapeutic Innovation & Regulatory Science. 2025. 59:112-124 DOIReview article
Peer-reviewed overview of FDA peptide compounding regulations and enforcement trends.
The regulatory landscape is moving fast
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Related content
Kennedy Peptide Reclassification
The announcement that could move ~14 peptides from Category 2 to Category 1.
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PeptideBPC-157
Research profile for one of the most discussed Category 2 peptides.
PeptideSemaglutide
An FDA-approved peptide that illustrates the regulatory pathway for Category 1 compounds.
GuideWhat Are Peptides?
A foundational primer on peptide science — helpful context for understanding FDA classification.
Disclaimer
This article reflects the FDA's bulk drug substance categorization as of March 2026. Categories are subject to change through ongoing FDA evaluation and reclassification proceedings. This is for educational purposes only and does not constitute medical or legal advice. Always consult a licensed healthcare provider before using any peptide product.