Category 1 vs Category 2 peptides: the access framework
Not all peptides have the same legal access path. The FDA's compounding framework creates three distinct lanes — and knowing which lane a peptide is in tells you a lot about what's available and what isn't.
TL;DR
- The FDA's 503A compounding framework includes a "Bulk Drug Substances" list that determines which compounds can be used by state-licensed compounding pharmacies — peptides not on this list cannot legally be compounded.
- FDA's interim policy of not taking action against compounding with a substance not yet on the bulks list applies only to Category 1 substances; FDA says Category 2 substances raise significant safety risks.
- In February 2026, HHS Secretary Robert F. Kennedy Jr. said in a podcast interview that FDA would soon make more peptides accessible. That was not a formal proposal; the formal step was FDA's April 2026 change to its category list.
What it is
Under Section 503A of the Federal Food, Drug, and Cosmetic Act, state-licensed compounding pharmacies may prepare customized medications for individual patients — but only using ingredients that appear on the FDA's approved Bulk Drug Substances (BDS) list, or meet other specific criteria. For peptides, the FDA has been working through a multi-year evaluation process to determine which compounds belong on this list. The terms "Category 1" and "Category 2" emerged from this process as shorthand for the FDA's interim access determinations.
How it works
The FDA's Pharmacy Compounding Advisory Committee (PCAC) evaluates nominated bulk drug substances and provides recommendations to the agency. Based on this process, peptides were sorted into categories reflecting the FDA's current assessment of available safety and efficacy data. Category 1 means the substance is under evaluation. FDA's interim policy of not taking action against compounding with a substance not yet on the bulks list applies only to Category 1 substances, when other conditions are met. Category 2 designation indicates the FDA has identified significant safety concerns — or insufficient human safety data — that preclude interim eligibility for compounding. FDA added 19 peptides to Category 2 on September 29, 2023. FDA removed 5 of them on September 27, 2024, and 12 more on April 22, 2026, after their nominations were withdrawn. In February 2026, HHS Secretary Robert F. Kennedy Jr. said in a podcast interview that FDA would soon make more peptides accessible. That was not a formal proposal; the formal step was FDA's April 2026 change to its category list.
Who asks about it
People come to this topic when they've heard about specific peptides — often BPC-157 or TB-500 — and want to understand where they stand with FDA. The Category 1 / Category 2 framework is the starting point: Category 2 is not an outright ban, and a substance's status can change after further FDA review. FDA removed BPC-157 and TB-500 from Category 2 on April 22, 2026, after their nominations were withdrawn. As of September 14, 2026, neither is in any FDA 503A category, and neither is on the 503A bulks list. As of September 2026, FDA has not made a final decision on BPC-157 or TB-500. At its July 23–24, 2026 meeting, FDA's Pharmacy Compounding Advisory Committee voted separately on each. Both votes were 8 yes, 6 no, and 1 abstention to recommend adding the peptide to the Section 503A bulk drug substances list. The committee is advisory, and formal addition to the list requires further FDA action.
What the research says
The FDA's PCAC process is documented through publicly available meeting minutes and Federal Register notices. FDA added 19 peptides to Category 2 on September 29, 2023. In February 2026, HHS Secretary Robert F. Kennedy Jr. said in a podcast interview that FDA would soon make more peptides accessible. That was not a formal proposal; the formal step was FDA's April 2026 change to its category list.
What to know before considering it
FDA's interim policy of not taking action against compounding with a substance not yet on the 503A bulks list applies only to Category 1 substances, when other conditions are met. Of the 19 peptides FDA added to Category 2 in 2023, only MK-677 (ibutamoren) and kisspeptin-10 remain in Category 2 as of September 14, 2026. Any product marketed as a Category 2 peptide for human use outside this framework does not carry the legal and quality-control safeguards of licensed compounding. Halftime Health only provides therapies through licensed physicians using legally eligible compounded or FDA-approved products. The reclassification process should be monitored at FDA.gov for updates.
The Halftime POV
The regulatory framework is genuinely complex, and that complexity exists for a reason — it's the mechanism by which patient safety is evaluated before a compound enters widespread clinical use. We think the most useful thing we can do is explain how this framework actually works, without either dismissing it or catastrophizing it. Understanding the categories makes you a better-informed participant in the conversation about which therapies are appropriate and available now.
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FAQ
Q: What is the FDA's Category 1 vs Category 2 peptide classification? A: The FDA evaluates bulk drug substances nominated for compounding under 503A pharmacies. Category 1 is FDA's list of substances under evaluation. FDA's interim policy of not taking action against compounding with a substance not yet on the 503A bulks list applies only to Category 1 substances, when other conditions are met. Category 2 is FDA's list of substances that raise significant safety risks.
Q: Which peptides are currently Category 1? A: On FDA's category list last updated May 14, 2026, Category 1 includes NAD, NADH, vasoactive intestinal peptide, glutathione, methylcobalamin, enclomiphene citrate, and GHK-Cu except injectable routes. The FDA maintains a current list at FDA.gov; always verify current status, as it can change.
Q: What is the path from Category 2 back to Category 1? A: FDA changes its category list by posting an updated list. The list was last updated May 14, 2026. On April 22, 2026, FDA removed 12 peptides from Category 2 after their nominations were withdrawn. Those peptides went to no category, not to Category 1. In February 2026, HHS Secretary Robert F. Kennedy Jr. said in a podcast interview that FDA would soon make more peptides accessible. That was not a formal proposal; the formal step was FDA's April 2026 change to its category list.
Disclaimer
Several peptides discussed in this article — including KPV, MOTS-c, DSIP, epitalon, and Semax — were previously in FDA's Category 2. FDA removed them from Category 2 on April 22, 2026. As of September 14, 2026, they are not in any FDA 503A category and are not on the 503A bulks list. As of September 2026, FDA has not made a final decision on BPC-157 or TB-500. At its July 23–24, 2026 meeting, FDA's Pharmacy Compounding Advisory Committee voted separately on each. Both votes were 8 yes, 6 no, and 1 abstention to recommend adding the peptide to the Section 503A bulk drug substances list. The committee is advisory, and formal addition to the list requires further FDA action. This article is educational and is not medical advice. Halftime Health only prescribes through licensed physicians in states where our partner physicians are credentialed.
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Sources
- FDA. "Bulk Drug Substances That May Be Used in Compounding Under Section 503A of the Federal Food, Drug, and Cosmetic Act." FDA.gov
- FDA. PCAC Meeting Materials, 2023. FDA.gov
- Robert F. Kennedy Jr., HHS Secretary. Remarks on peptides, The Joe Rogan Experience podcast, February 27, 2026. HHS issued no press release or Federal Register notice.
This article discusses compounds whose FDA compounding status has been under review (see our FDA categorization explainer). Halftime Health protocols are prescribed by licensed physicians and prepared by licensed 503A compounding pharmacies. Compounded drugs are not FDA-approved and have not been evaluated by FDA for safety or effectiveness. This article is provided for educational purposes only and does not constitute medical advice or an offer to sell.
Frequently asked questions
What is the FDA's Category 1 vs Category 2 peptide classification?
The FDA evaluates bulk drug substances nominated for compounding under 503A pharmacies. Category 1 is FDA's list of substances under evaluation. FDA's interim policy of not taking action against compounding with a substance not yet on the 503A bulks list applies only to Category 1 substances, when other conditions are met. Category 2 is FDA's list of substances that raise significant safety risks.
Which peptides are currently Category 1?
On FDA's category list last updated May 14, 2026, Category 1 includes NAD, NADH, vasoactive intestinal peptide, glutathione, methylcobalamin, enclomiphene citrate, and GHK-Cu except injectable routes. The FDA maintains a current list at FDA.gov; always verify current status, as it can change.
What is the path from Category 2 back to Category 1?
FDA changes its category list by posting an updated list. The list was last updated May 14, 2026. On April 22, 2026, FDA removed 12 peptides from Category 2 after their nominations were withdrawn. Those peptides went to no category, not to Category 1. In February 2026, HHS Secretary Robert F. Kennedy Jr. said in a podcast interview that FDA would soon make more peptides accessible. That was not a formal proposal; the formal step was FDA's April 2026 change to its category list.
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