An FDA advisory panel vote on six peptides has placed AOD-9604 and retatrutide under fresh regulatory scrutiny. The vote signals divergent paths for these compounds under 503A and 503B compounding frameworks.
The Panel Vote and Its Immediate Scope
The panel evaluated six peptides for inclusion on a list of bulk drug substances that may not be compounded. AOD-9604, a fragment of human growth hormone, faced questions about clinical evidence. Retatrutide, a triple agonist still in trials, drew attention for its novelty and potency.
There are three reasons the vote matters: 1) it sets a precedent for peptide oversight, 2) it affects compounding pharmacy access, and 3) it clarifies FDA's stance on research chemicals. The panel's decision is advisory, but the agency often follows such recommendations.
AOD-9604: A Legacy of Ambiguity
AOD-9604 has been marketed for weight loss since the early 2000s. A 2019 trial showed modest effects on fat mass in obese subjects, but the panel rated this evidence a 2 of 3 on quality. The compound lacks FDA approval for any indication.
Under 503A, a pharmacy may compound AOD-9604 if it appears on the FDA's positive list. The panel's vote could remove it from that list. This would force patients to seek alternatives through clinical trials or unregulated channels.
For a deeper look at AOD-9604's regulatory history, see AOD-9604 and FDA's Peptide Panel Vote.
Retatrutide: A Newer, Riskier Profile
Retatrutide targets GLP-1, GIP, and glucagon receptors. A 2022 review noted its superior weight loss in phase 2 trials, but long-term safety data are absent. The panel flagged this gap as a 1 of 3 on evidence quality for compounding safety.
Because retatrutide is not yet FDA-approved, it cannot be legally compounded from bulk substances under 503A. Some pharmacies have used 503B outsourcing facilities, but the panel's vote may close that path. The FDA has already issued warning letters over retatrutide compounding, as covered in Retatrutide Compounding Crackdown.
Divergent Paths: Why the Panel Treats Them Differently
AOD-9604 has a longer safety record, albeit weak efficacy data. Retatrutide has stronger efficacy signals but no long-term safety profile. The panel applied a risk-benefit framework that weighs these factors differently.
For AOD-9604, the question is whether marginal benefit justifies continued compounding. For retatrutide, the question is whether any compounding is safe before approval. This distinction drives the divergence in regulatory paths.
The UK's recent pill approval for retatrutide adds another layer, as discussed in Retatrutide vs AOD-9604: UK Pill Approval Shifts Regulatory Path.
Who Is Affected: Compounders, Patients, and Researchers
Compounding pharmacies face immediate operational changes. If AOD-9604 is removed from the positive list, 503A pharmacies must stop compounding it. 503B facilities may face similar restrictions for retatrutide.
Patients using these peptides for weight loss or metabolic conditions will lose access. Some may turn to unregulated sources, increasing safety risks. Researchers must navigate new restrictions on obtaining bulk substances.
Secondary compounds like oxytocin, Vesugen, PT-141, and IGF-1 LR3 may also be affected if the panel's reasoning extends to them. The vote sets a template for future peptide evaluations.
What to Watch Next
The FDA will issue a final rule based on the panel's recommendation. That rule will specify which peptides are prohibited from compounding. Legal challenges are possible from compounding pharmacies and patient advocacy groups.
Clinical trial data for retatrutide will continue to emerge, potentially altering the risk calculus. For AOD-9604, any new efficacy studies could revive its prospects. The regulatory landscape for peptides is shifting rapidly.
For ongoing coverage of retatrutide's regulatory risks, see Retatrutide Compounding Risks Amid FDA GLP-1 Quality Concerns.
Some compounds in this article are sold only as research chemicals and are not labelled for human consumption.