Peptide Policy Watch

FDA compounding categories explained: what Category 1 and Category 2 mean

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Sign reading U.S. Department of Health and Human Services, Food and Drug Administration, with a campus office building behind it.
FDA campus entrance sign, with Building 21 behind it. Illustrative photo. Photo: The U.S. Food and Drug Administration, Public domain. Image credits

Published October 25, 2026. Status is "as of" this date. Sources and retrieval dates are at the bottom. This is not medical advice. The site owner is not a medical professional. Nothing here is a recommendation to use any substance.

Key facts (from the sources below)

  • FDA's interim policy describes three categories for nominated bulk substances: Category 1 (under evaluation), Category 2 (significant safety risks) and Category 3 (not enough support).
  • For Category 1, FDA says it "does not intend to take action against a compounder" if the conditions in FDA's guidance are met.
  • For Category 2, the Category 1 policy does not apply. FDA says it "would consider taking action against a compounder" under its general enforcement policies.
  • A guidance document says FDA does not intend to place substances nominated on or after January 7, 2025, into these categories.
  • None of these categories makes a compounded drug an FDA-approved drug.

What this means in plain English

  • The categories describe FDA's enforcement stance while it evaluates nominations. They are not approvals and not bans.
  • Category 1 is about the stage of evaluation. Category 2 is about identified risks in compounding.
  • "Removed from Category 2" means a list change. Look for the reason: here, the nominators withdrew.
  • A committee recommendation is an advisory vote that FDA is not bound to follow.

If you follow peptide news, you will see "Category 1" and "Category 2" used as if they were approvals or bans. They are neither. This explainer describes what FDA says the categories are, using FDA's own documents, and what they are not.

First, the setting: 503A bulk drug substances

Compounding means a pharmacist or physician makes a customized drug rather than dispensing a mass-produced, FDA-approved one. Section 503A of the federal Food, Drug, and Cosmetic Act covers compounding by state-licensed pharmacies, federal facilities and licensed physicians. FDA maintains a "503A bulks list" of bulk drug substances that can be used in this compounding. FDA's 503A page says a final regulation in February 2019 placed six substances on the list, and that FDA issued a proposed regulation in September 2019 that would add more (FDA 503A page).

FDA says it handles nominated substances on a rolling basis through notice-and-comment rulemaking. So FDA created an interim policy describing when it does not intend to take enforcement action while it evaluates nominations. The three categories come from that interim policy.

What's confirmed

What the three categories mean

All definitions below are paraphrased from FDA's page and category list.

Category 1: under evaluation. The substance was nominated with enough supporting information for FDA to evaluate it, and does not appear on any other list. FDA says it "does not intend to take action against a compounder" for compounding with a Category 1 substance, provided the conditions in FDA's guidance are met.

Category 2: significant safety risks. The substance was also nominated with enough information to evaluate, but FDA identified significant safety risks in compounding it. The Category 1 policy does not apply. FDA says it "would consider taking action against a compounder" under its general enforcement policies. When FDA adds a substance, it says it will publish the safety information.

Category 3: not enough support. The nomination did not include enough information for FDA to evaluate the substance. It is not covered by the Category 1 policy, and FDA says it would consider taking action under general policies. It can be re-nominated with better support.

One more rule from FDA's page: a guidance document says FDA does not intend to place substances nominated on or after January 7, 2025, into these categories. Newer nominations are therefore handled outside the category system.

The three categories at a glance

  1. Category 1Under evaluation

    Nominated with enough information for FDA to evaluate. FDA says it "does not intend to take action against a compounder" if the conditions in FDA's guidance are met.

  2. Category 2Significant safety risks

    FDA identified significant safety risks in compounding it. The Category 1 policy does not apply. FDA says it "would consider taking action against a compounder" under its general enforcement policies.

  3. Category 3Not enough support

    The nomination did not include enough information for FDA to evaluate. It is not covered by the Category 1 policy. It can be re-nominated with better support.

None of these categories makes a compounded drug an FDA-approved drug.

Source: FDA's category page and list, paraphrased in this post (FDA update of May 14, 2026; retrieved October 25, 2026).

What it means

What the categories are not

  • Not an approval. FDA's page and list describe an enforcement posture while evaluation is pending. None of these categories makes a compounded drug an FDA-approved drug.
  • Not a final decision. FDA says Category 1 substances remain within the interim policy "until the agency decides on inclusion" on the bulks list, or removes them, for example because of safety information.
  • Not a verdict that a substance is safe or unsafe in general. Category 2 is about identified risks in compounding. Category 1 is about the stage of evaluation.

What is on the lists today (FDA update of May 14, 2026)

FDA's list is long, so these examples are illustrative only.

  • Category 1 includes glutathione, nicotinamide adenine dinucleotide (NAD and NADH), vasoactive intestinal peptide, and "GHK-Cu (except for injectable routes of administration)." FDA's list notes GHK-Cu was removed from Category 1 on April 22, 2026, after nominations were withdrawn. A nominator clarified on May 5 that it meant to withdraw only the injectable route, so the non-injectable portion was added back on May 14. FDA also said it intends to consult its advisory committee on GHK-Cu before the end of February 2027.
  • Category 2 names six substances: cesium chloride, domperidone, germanium sesquioxide, ibutamoren mesylate, kisspeptin-10, and quinacrine hydrochloride for intrauterine administration. For two peptide-related examples, FDA's safety page says ibutamoren mesylate poses significant risk because of the potential for congestive heart failure in certain patients, citing a trial "terminated early due to a potential safety signal of congestive heart failure." For kisspeptin-10, FDA says compounded drugs "may pose risk for immunogenicity" for certain routes, and that FDA has limited safety information for the proposed routes.
  • Category 3 includes GHRP-2, GHRP-6, mechano growth factor (MGF), thymulin acetate and cibinetide (ARA-290), among many others.

The same substance can be treated differently under the 503A and 503B rules. For example, FDA's safety page lists GHRP-2 (for injectable and nasal routes of administration) and GHRP-6 under Category 2 for 503B (added September 29, 2023), while the 503A list places them in Category 3. Section 503B covers outsourcing facilities, a different compounding route with its own bulks list (FDA 503B page).

"Nominated but withdrawn"

FDA's safety page also has a section for substances "previously in category 2" that were "withdrawn by the nominators." It lists AOD-9604, BPC-157, cathelicidin LL-37, CJC-1295, dihexa acetate, emideltide, epitalon, KPV, MOTS-c, selank acetate, semax, thymosin alpha-1, TB-500 and others. That page still shows FDA's description of potential risks for each. A withdrawn nomination removes the substance from the category. It does not say FDA concluded the risks were resolved. Some of these substances were later reviewed by FDA's advisory committee on the 503A list. See our timeline.

What it means

How to read a headline

  1. "Removed from Category 2" means a list change. Look for the reason: here, the nominators withdrew.
  2. "Added to Category 1" means FDA is evaluating it and has a limited enforcement policy, not that it approved it.
  3. "Recommended by the committee" is an advisory vote that FDA is not bound to follow.

Sources (all retrieved October 25, 2026; the FDA pages were re-opened that day)

  1. FDA, "Bulk Drug Substances Used in Compounding Under Section 503A of the FD&C Act" — https://www.fda.gov/drugs/human-drug-compounding/bulk-drug-substances-used-compounding-under-section-503a-fdc-act
  2. FDA, 503A category list (PDF), updated May 14, 2026 — https://www.fda.gov/media/94155/download
  3. FDA, "Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks," content current as of 04/22/2026 — https://www.fda.gov/drugs/human-drug-compounding/certain-bulk-drug-substances-use-compounding-may-present-significant-safety-risks
  4. FDA, 503B bulk drug substances page — https://www.fda.gov/drugs/human-drug-compounding/bulk-drug-substances-used-compounding-under-section-503b-fdc-act

Reading this for health reasons? This site reports on regulation; it is not medical advice. See our disclaimer, how we source and corrections policy.