Weight Loss & Metabolic
AOD-9604 and MOTS-c FDA Status
FDA has identified serious adverse events that may be associated with AOD-9604, and no human exposure data for MOTS-c
Both substances are sold into weight-management and metabolic practice. Neither is an FDA-approved drug for weight loss, and the regulatory conversation clinics are having about GLP-1 medicines does not transfer to either of them. This page sets out what the federal record showed when we checked it in September 2026, substance by substance, with the documents linked so a clinic and its counsel can read FDA rather than our summary of FDA.
AOD-9604 and MOTS-c: Neither appears on the 503A Bulks List at 21 CFR 216.23, the 503B Bulk Drug Substances List, 21 CFR 216.24, or either nominations document. We also checked FDA’s drug shortage database and did not identify either substance, or a drug product containing either. Both sit instead on FDA’s safety-risks page under “bulk drug substances nominated but withdrawn” — substances “previously in category 2 of the interim policies” that “were withdrawn by the nominators.” On the federal sources reviewed in September 2026 we did not identify a 503A or 503B basis permitting either substance to be compounded from bulk under the circumstances reviewed here.
Both went before the advisory committee. AOD-9604 on 4 December 2024, MOTS-c on 23 July 2026, each in free base and acetate form. In both cases FDA’s briefing document stated that the evaluation criteria weighed against placing either form on the 503A Bulks List.
Absence from a list is not, by itself, a complete legal analysis. The statutory conditions, the formulation, the facility’s status, whether supply is against a prescription for an identified individual or for office use, and state requirements are separate questions.
Regulatory tracking only. Not medical or legal advice.
HOW WE SUPPORT CLINICS
Phoenix Meds Regulatory Support Model
Status Established Per Substance
Each substance is checked independently against both bulks lists, both nominations documents, 21 CFR 216.24 and the safety-risks page. Sharing a category tells you nothing about sharing a status.
The Nomination Record
What a substance was nominated for, what happened to that nomination, and which FDA document carries the outcome. Withdrawal and rejection are not the same event.
Separating the GLP-1 Question
Semaglutide, tirzepatide and liraglutide have their own compounding record, addressed by FDA in its own notice. It has no bearing on the substances covered here, and we say so in writing.
Supplier Claims Checked
Where a supplier asserts a statutory basis, we compare the assertion against the available primary record and document what that record shows. The clinic and its advisers determine the legal significance.
Dated Record Assembly
Where a clinic is building its own file, we set out what the published FDA record shows and the date each item was checked. The clinic and its advisers decide what follows.
Primary-Source Documentation
The publicly available regulatory record organised and linked, so a clinic can review FDA’s own language with its qualified advisers rather than a summary of it.
Whether a particular product may lawfully be compounded, prescribed, dispensed or administered depends on the substance, the formulation, the route, the prescription, and applicable federal and state law. That determination rests with the clinic, the pharmacy and their own counsel.
REGULATORY SUPPORT DELIVERED
Clinic Benefits
In a category this heavily marketed, knowing what FDA actually wrote is worth more than knowing what a supplier claims it means.
✓ Adverse Event Language Surfaced
FDA recorded serious adverse events that may be associated with one substance on this page. That language is material to understanding the agency’s current safety assessment.
✓ Human Data Position Stated
What FDA says it found, and did not find, about administration to humans — quoted from the agency’s own documents rather than characterised.
✓ Fragment Reasoning Checked
Being a fragment of an approved protein is not the same as being a component of an approved drug product. We set out why, with the statutory language.
✓ Both Documents Checked
The 503A and 503B nomination categories live in separate documents with different contents. We check both and record the result, including absence.
✓ Withdrawal Explained
A nomination withdrawn by its nominator is not a substance cleared by FDA. The distinction decides more than most sourcing conversations acknowledge.
✓ Dated, Re-Checkable Findings
Every finding carries the date it was checked and the document it came from, so a clinic can re-run the check itself at any point.
Credentials describe a facility, not an input. A facility’s registration status does not, by itself, establish that a particular bulk substance satisfies the applicable requirements for compounding.
Weight Management in Clinical Practice
Metabolic and weight-management practice has expanded quickly, and the substances offered into it now range from approved prescription medicines to bulk peptides with no approved product behind them. Clinics working in this space face a genuine clinical question about whom to treat and how, and a separate question about what a pharmacy may lawfully prepare. This page addresses only the second.
Those two questions get run together more often here than in any other category we track, and the reason is structural. A prescriber exercising ordinary discretion about an approved weight-management drug is on familiar ground. That discretion is real, and it is not the subject of this page. That clinical discretion is separate from the question of whether a particular pharmacy or outsourcing facility has an applicable basis to compound the preparation being requested. The distinction between the two sections, and what each requires, is set out on our legal and regulatory status page.
Nothing on this page suggests that either substance addresses obesity, body composition, metabolic disease or any other condition. What each was nominated for is a matter of record and is set out below. What either does in a person is not something this page states, because the federal record we reviewed does not establish it.
The Two Substances in This Category
AOD-9604
AOD-9604 is described by FDA as “a hexadecapeptide, i.e., it contains 16 amino acids” — “a synthetic fragment of human growth hormone (hGH) (15 amino acids: 177-191) with an additional tyrosine.” FDA’s December 2024 materials place that tyrosine at the N-terminal end in one passage and the C-terminal in another, so we do not use the positional description to identify the substance, and neither should a certificate of analysis. FDA evaluated the free base and the acetate separately ahead of the advisory committee meeting of 4 December 2024; its briefing document, dated 5 November 2024, records the nominated uses as “weight loss, osteoporosis and osteoarthritis”, of which it evaluated obesity.
What FDA concluded about eligibility. The briefing document addresses the 503A conditions directly. On the approved-drug-component condition it states plainly: “neither is a component of an FDA-approved drug.” The monograph condition gets the same treatment: “There is no applicable United States Pharmacopeia (USP) or National Formulary (NF) drug substance monograph.” On the list itself, FDA “believes the evaluation criteria weigh against placing AOD-9604 (free base) or AOD-9604 acetate on the list”, and describes both as “not physically and chemically well characterized.” That covers all three of the section 503A conditions in FDA’s own language rather than our reading of it, and it is the passage to hand to counsel.
Regulatory position, checked September 2026. AOD-9604 does not appear on the 503A Bulks List at 21 CFR 216.23, on the 503B Bulk Drug Substances List, on 21 CFR 216.24, or in either nominations document. It sits instead in the safety-risks page’s table of substances nominated but withdrawn — previously category 2, the category titled “Bulk Drug Substances that Raise Significant Safety Risks”, withdrawn by the nominators. Category placement is a historical marker rather than a current classification scheme: FDA “does not intend to place bulk drug substances nominated on or after January 7, 2025, into these categories.”
Two FDA documents, and the dates matter. In November 2024 the briefing document recorded that “The FAERS search did not retrieve any reports, and the literature search did not identify any literature cases”, alongside a concern about immunogenicity in an injectable formulation arising from aggregation and peptide-related impurities. The safety-risks page, content current 22 April 2026, goes further: “Compounded drugs containing AOD-9604 may pose significant risk for immunogenicity for certain routes of administration and may have complexities with regard to peptide-related impurities and API characterization. FDA has identified no, or only limited, safety-related information. Therefore, the agency lacks sufficient information to know whether the drug would cause harm when administered to humans. FDA has also identified serious adverse events that may be associated with AOD-9604, though causality is not clear.” The later statement is the current one. FDA asserts an association and expressly declines to assert causation, and that is how the finding should be carried into any file.
Our finding. On the sources reviewed in September 2026 we did not identify a condition under section 503A or section 503B satisfied by AOD-9604 in either form.
MOTS-c
MOTS-c is a short peptide encoded within the mitochondrial genome. FDA writes the name as “MOTS-c” in its meeting materials and “MOTs-C” on its safety-risks page; the agency’s own briefing document notes inconsistent naming conventions for this substance that do not follow established chemical nomenclature standards.
Regulatory position, checked September 2026. MOTS-c does not appear on either bulks list, on 21 CFR 216.24, or in either nominations document. We did not identify an FDA-approved drug product containing MOTS-c, or an applicable USP or NF drug-substance monograph, in the sources reviewed. Like AOD-9604 it sits in the nominated-but-withdrawn table on the safety-risks page, alongside the two substances covered on our injury recovery and tissue repair page.
What the advisory committee reviewed. MOTS-c was before the Pharmacy Compounding Advisory Committee on 23 July 2026, with each form evaluated separately. FDA’s briefing document, dated 11 May 2026, records the nomination as covering “insulin resistance, obesity, osteoporosis, vascular calcification, muscle/fat metabolism, longevity”. For the meeting itself FDA listed the use evaluated more narrowly, as “Obesity and osteoporosis”. What a substance was nominated for and what FDA went on to evaluate are different things, and suppliers quote the wider list. The briefing document concluded that the evaluation criteria weighed against placing either form on the 503A Bulks List.
The same document states: “Published literature did not reveal studies in which compounded drug products containing MOTS-c or MOTS-c acetate were used in humans.” FDA’s safety-risks entry puts it a second way: “FDA has not identified any human exposure data on drug products containing MOTs-C administered via any route of administration.”
Our finding. On the sources reviewed in September 2026 we did not identify a condition under section 503A or section 503B satisfied by MOTS-c in either form. No minutes, transcript or vote record for the July 2026 meeting turned up in the materials we reviewed; accounts of how the committee voted come from trade press.
An advisory recommendation does not itself amend either list. The 503A Bulks List is codified at 21 CFR 216.23, and substances are added to it or removed from it through notice-and-comment rulemaking, not by a committee vote. Until that process runs, the list reads as it reads.
The Evidence and What FDA Recorded
Preclinical literature exists for both substances and we are not disputing it. Trade press also reports historical human trials of AOD-9604 in obesity; we did not verify that from a primary source, and it would establish nothing regulatory in either direction if we had.
What matters for a sourcing decision is narrower, and FDA has stated it plainly for each substance. For MOTS-c the agency identified no human exposure data by any route. For AOD-9604 it identified no, or only limited, safety-related information, together with serious adverse events of unclear causality. Those are the agency’s characterisations, in the agency’s words, and they are more specific than anything a marketing page will tell a clinic.
What follows for a practice, stated without inference:
- FDA stated that it had not identified human exposure data for drug products containing MOTs-C administered by any route, and that it had identified no, or only limited, safety-related information for AOD-9604.
- FDA described both AOD-9604 forms as not physically and chemically well characterized, and recorded concerns about peptide-related impurities and API characterization for both substances.
- Neither substance has been placed on either Bulks List, so no FDA evaluation of a specific formulation, strength or route sits behind either one.
- FDA has stated of AOD-9604 that neither form is a component of an approved drug. For MOTS-c, no such product appeared in the sources we reviewed.
The FDA materials reviewed here do not establish an approved clinical protocol for either substance in weight management. Any clinical decision, and the responsibility for it, rests with the prescriber. None of the above is a recommendation to use these compounds.
Why Clinics Have Explored These Peptides
Demand for metabolic and weight-management services has grown faster than the supply of approved options that fit every practice and every clinical circumstance. Clinics report interest from people who have not tolerated or not accessed approved medicines, and the peptide market has moved into that space energetically, with claims that outrun what any regulator has evaluated.
Observing that a market exists is not endorsing it. Interest in a substance is not evidence about the substance, and a supply chain’s willingness to sell says nothing about whether a pharmacy may lawfully compound from bulk. Nothing in this section should be read as a suggestion that a clinic add either substance to its offering.
Two Questions Specific to This Category
A fragment is not a component
AOD-9604 corresponds to a fragment of human growth hormone, and approved somatropin products exist. That reasoning does not establish AOD-9604 as a component of an FDA-approved drug product. Section 503A’s condition is that the bulk drug substance is a component of such a product. The approved products contain full-length somatropin. A shorter peptide with a different sequence and a different molecular identity is a different substance, whatever it was derived from.
Ask any supplier making this argument to name the approved product, the application number, and the component as it appears in that product’s formulation. The answer should be requested in writing and retained with the sourcing file.
The GLP-1 conversation does not transfer
Semaglutide, tirzepatide and liraglutide dominate discussion of compounded weight-management products, and clinics reasonably assume the reasoning extends across the category. It does not. Those substances have approved products, which engages the “essentially a copy” restrictions — a harder position for a compounder, not an easier one — and FDA addressed their bulk status directly in a notice published on 1 May 2026, proposing that none of the three be included on the 503B Bulks List.
None of that reasoning reaches AOD-9604 or MOTS-c, for which we did not identify an FDA-approved product in the sources reviewed. They raise a different question entirely. A supplier moving between the two conversations is not describing one regulatory position; it is changing the subject.
What to Verify Before Any Sourcing Decision
Start with the name on the paperwork. FDA’s own briefing document criticises the naming conventions used for MOTS-c as not following established chemical nomenclature standards, and the agency writes the substance two different ways across two of its own documents. Ask for the sequence, the salt or free base form, and the CAS number, and check that all three agree across the certificate, the invoice and the label. Where they do not, you do not yet know what has been quoted to you.
Then ask which statutory condition the supplier says is satisfied, under which section, and ask for the document itself rather than a description of it. Establish whether you are dealing with a 503A pharmacy filling a prescription for an identified individual or a 503B facility supplying office stock, because the qualifying conditions differ and a registration number answers neither question.
Two claims specific to this category deserve written answers. If a supplier argues that AOD-9604 reaches the approved-drug-component condition through growth hormone, ask it to name the approved product and its application number, and to identify the substance as a component of that product’s formulation. If a supplier reasons from the compounded GLP-1 market, ask which of the substances you are actually buying it is describing. And ask what the supplier does with FDA’s safety language: the agency has recorded serious adverse events that may be associated with AOD-9604, and that finding belongs in the file.
On research-use material: Research Use Only or Not for Human Use labelling does not settle how FDA treats a product. Under 21 CFR 201.128 intended use may be determined from expressions, the design or composition of the article, and the circumstances surrounding its distribution — website copy, how a product is described to buyers, and distribution practice, alongside the label. In a warning letter dated 17 June 2026 to a distributor in Brooksville, Florida, FDA concluded two products were unapproved new drugs on the evidence of the firm’s own marketing, whatever the labelling said. That letter concerned that firm and those products.
State Law Sits On Top of This
This page addresses federal requirements only. State pharmacy, medical practice, prescribing and dispensing rules apply in addition and are cumulative, never a substitute. Several states have moved separately on compounded weight-management products, and a state board’s position on office-use supply, distributor registration or a particular substance can restrict what federal law would otherwise permit. Professional liability cover is a further question again, and exclusions for unapproved products are not unusual. Check all three with your own advisers.
Availability Through Phoenix Meds
Sourcing Position (September 2026)
For AOD-9604 and MOTS-c, singly or combined, we did not identify a satisfied statutory condition under section 503A or section 503B. Where a clinic asks us to arrange either, we set out that finding in writing first, with the sources and the date, before anything is ordered.
Phoenix Meds does not determine whether a preparation is lawful. We document what the FDA record shows so the clinic and its counsel can.
What we do here is unglamorous and specific. We check each substance on its own against every federal list that could apply, we quote FDA’s safety text in full including the parts that do not help anyone sell anything, we distinguish a nomination that was withdrawn from a substance that was cleared, and we keep the GLP-1 record in its own lane where it belongs. Where an applicable federal and state-law basis can be independently established for a particular transaction, we may coordinate sourcing through appropriately licensed pharmacy partners. We do not treat a supplier’s representation as establishing that basis.
If a supplier has offered you either substance on the strength of a fragment argument, a withdrawn nomination, or the GLP-1 compounding debate, that is worth knowing before you order rather than after.
If FDA opens a rulemaking, amends either Bulks List, or alters either nominations document in a way that affects these substances, we update this page and re-date it.
Verify This Yourself
The regulatory and factual statements above are based on these public sources, each checked in September 2026. Where the page draws an inference, it says so.
FDA — bulk substances that may present significant safety risks — the nominated-but-withdrawn table, and the full safety text quoted above for both substances. Content current 22 April 2026.
FDA briefing document — AOD-9604 — the eligibility findings, the sequence and the FAERS result quoted above. Dated 5 November 2024.
FDA — PCAC meeting, 4 December 2024 — where AOD-9604 was reviewed. Minutes and both transcripts published.
FDA briefing document — MOTS-c — the nomination scope and the human-use finding quoted above. Dated 11 May 2026.
FDA — PCAC meeting, 23–24 July 2026 — the substances and the uses evaluated. No minutes, transcript or vote record published.
21 CFR 216.23 — the 503A Bulks List. Neither substance appears. Current as of 1 September 2026.
21 CFR 216.24 — the separate bar on withdrawn or removed products. Neither substance appears.
FDA — 503B Bulk Drug Substances List — five substances; neither of ours. Shows “Updated August 21, 2023”, content current 16 May 2024.
FDA Drug Shortages database — the second 503B route. Neither substance, and no product containing either, appeared.
FDA — substances nominated under section 503A — the 503A nomination categories. Neither substance appears. Updated 14 May 2026.
FDA — substances nominated under section 503B — a separate document with different contents. Neither substance appears. Updated 21 March 2025.
FDA — bulk drug substances used in compounding under section 503A — carries the statement that FDA “does not intend to place bulk drug substances nominated on or after January 7, 2025, into these categories.” Content current 14 May 2026.
Federal Register, 1 May 2026 — FDA’s GLP-1 notice, cited only to show that question is a separate one.
21 CFR 201.128 — how intended use is established from the circumstances surrounding distribution.
Related Clinic Resources
Disclaimer and regulatory scope
This page is regulatory information for licensed clinics, compiled from publicly available FDA materials. It is not medical or legal advice, and it is not a determination that any product, formulation, pharmacy, outsourcing facility or protocol is lawful. Work with qualified counsel in your state.
On the federal sources reviewed in September 2026 we did not identify a 503A or 503B basis permitting AOD-9604 or MOTS-c to be compounded from bulk under the circumstances reviewed here. That is our finding on those sources at that time, not a legal conclusion. This page addresses federal requirements; state law may add restrictions.
Phoenix Meds Inc. is not a pharmacy, clinic, prescriber or medical provider, and we do not dispense medications. We coordinate sourcing between licensed clinics and licensed pharmacies in the United States. Any compounded preparation is prepared, dispensed and shipped by the pharmacy or outsourcing facility. Our pharmacy partners represent that they are state-licensed 503A pharmacies or FDA-registered 503B outsourcing facilities.
Compiled from primary FDA sources, which are linked above so readers can check each statement directly. Last reviewed: September 2026.