U.S. regulatory status
Dihexa
Also known as Dihexa acetate, PNB-0408, ATH-1001
Is Dihexa legal right now?
Dihexa is an experimental synthetic compound that was nominated to FDA for compounding as dihexa acetate.
It is not FDA-approved and not on the 503A bulks list, so a U.S. pharmacy cannot lawfully compound it. FDA placed dihexa acetate in 503A Category 2 (significant safety risks) on September 29, 2023, and removed it on April 22, 2026 because the nominator withdrew its nomination.
Removal from Category 2 does not authorize compounding: only Category 1 substances get FDA’s interim enforcement discretion, and dihexa is now in no category. FDA’s Category 2 page still lists it, noting that FDA has not identified any human exposure data for it by any route.
Dihexa acetate is one of five substances - with LL-37, GHK-Cu, Melanotan II and PEG-MGF - on the agenda of a Pharmacy Compounding Advisory Committee meeting that FDA says it will host before the end of February 2027; no date or Federal Register notice has been published. The vote would be advisory, and dihexa could become compoundable only if FDA then added it to the 503A bulks list by rulemaking.
In limbo: Moved on paper - nominated, removed from a restricted list, or recommended by an FDA committee - but not added to the 503A list. The headline implies a change; the legal status has not moved.
Verified Oct 15, 2026 (ET) · status held since Apr 22, 2026
Where it sits in the process
- Nominated (passed)
- Under review (stalled here - not advancing)
- Rulemaking (not reached)
- Compounding-legal (not reached)
Not on a path to the 503A list right now. The process stalled or reversed at this stage - read the status above. Sitting at an earlier step is not a sign it will advance.
What changed last
No recorded changes yet - this entry has held one status since it was added.
Status elsewhere
| Jurisdiction | Status | Note |
|---|---|---|
| United States (FDA) | In limbo | Removed from 503A Category 2 on Apr 22, 2026 after the nomination was withdrawn; not on the 503A list; PCAC review expected before end of Feb 2027. |
| Australia (TGA) | Unscheduled | Not individually named in the Poisons Standard (October 2026) and no product on the ARTG; supply for human use is unlawful without ARTG registration, and the TGA is enforcing against unapproved peptides. |
| United Kingdom (MHRA) | Restricted | No UK marketing authorisation (not in the MHRA products substance index); supply as a medicine would be unlicensed. |
| European Union (EMA) | Restricted | No EU marketing authorisation or orphan designation (absent from the Union Register); sale as a medicine is unlawful EU-wide, with enforcement at member-state level. |
| Canada (Health Canada) | Restricted | No product in the Drug Product Database, so it has no DIN and cannot lawfully be sold as a drug; no Health Canada advisory names it. |
| Sport / anti-doping (WADA) | Restricted | Not individually named, but prohibited at all times under the S0 catch-all for non-approved substances (2027 List). |
The U.S. status is watched by automation every six hours. Statuses elsewhere change less often and are covered by a monthly wide-net sweep, then re-verified whenever a lead surfaces - this entry’s last-verified date covers every row above. How we track it
FDA warning letters
No FDA warning letter mentions dihexa. We search the FDA’s warning-letter index for it and its other names; last searched Oct 15, 2026 (ET).
A warning letter is the FDA telling one company it believes the company broke federal law. It does not change the status above. All warning letters, by compound
Sources & transparency
Sources for this entry
- FDA - Certain bulk drug substances that may present significant safety risks (Category 2 page) FDA · primaryLists dihexa acetate under ‘Bulk drug substances nominated but withdrawn’ with FDA’s stated safety concerns (content current as of Apr 22, 2026).
- FDA - Pharmacy Compounding Advisory Committee meeting, before the end of February 2027 (early announcement) FDA · primaryFDA: the committee will discuss Cathelicidin (LL-37), GHK-Cu, Dihexa acetate, Melanotan II and PEG-MGF; time and location “will be scheduled in the coming months”.
- FDA - 503A categories list (updated May 14, 2026) FDA · primaryDihexa acetate does not appear in Category 1, 2 or 3.
- FDA Global Substance Registration System - Dihexa (UNII 9WYX65A5C2) FDA · primaryChemical name and code names (PNB-0408, ATH-1001) used for the aliases.
- Therapeutic Goods (Poisons Standard - October 2026) Instrument 2026 Government · primaryNo entry for dihexa. Basis for the Australia (TGA) row, with an ARTG search returning no matches.
- Health Canada - Drug Product Database Health Canada · primaryNo product lists dihexa as an active ingredient (searched Oct 15, 2026). Basis for the Canada row.
- MHRA Products - substance index (D) UK gov · primaryNo dihexa entry. Basis for the United Kingdom (MHRA) row.
- EU Union Register of medicinal products (active substance index) EU · primaryNo dihexa entry. Basis for the European Union (EMA) row.
- WADA - 2027 Prohibited List (in force Jan 1, 2027) WADA · primaryNot named; S0 covers any substance with no current government approval for human therapeutic use, peptides included.
- FDA - 503A categories list, updated Apr 22, 2026 (Wayback Machine copy) Analysis’Dihexa Acetate’ has been removed from category 2 because the nomination was withdrawn by the nominator; PCAC consult planned before the end of February 2027.
- Last verified by a human
- Oct 15, 2026 (ET) · how we verify
- Who runs this
- Peptlas Research Team - independent. About us.
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This page reports publicly available regulatory status for information only. It is not medical or legal advice and makes no health claim. See our full disclaimer.
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