PCAC Briefing · Friday, July 24, 2026
Semax before the compounding committee
FDA proposes not adding either semax substance to the 503A Bulks List. Two things distinguish this evaluation: FDA says some of the available references demonstrated a lack of effectiveness rather than merely failing to demonstrate it, and it raises two specific pharmacological safety signals.
Published July 16, 2026 · By the Grey Peptides Editorial Board · ✓ Sourced from FDA's briefing document
| Substances | Semax (free base) and semax acetate |
| Also known as | ACTH(4-7)PGP |
| Length | 7 amino acids (heptapeptide) |
| Use FDA reviewed | Cerebral ischemia, migraine, and trigeminal neuralgia |
| Forms proposed | Subcutaneous injection and intranasal spray |
| Nomination | Nominations withdrawn; FDA evaluated at its own discretion |
| FDA staff position | Proposes not adding either form to the 503A Bulks List |
What FDA reviewed it for
FDA evaluated all three nominated uses: cerebral ischemia, migraine, and trigeminal neuralgia.
This is not a detail to skip past. FDA evaluates a bulk drug substance in the context of the use proposed for it — so the question in front of the committee is not "is Semax useful?" but "does the evidence support compounding Semax for cerebral ischemia, migraine, and trigeminal neuralgia?" A substance can have an interesting research literature in a completely different area and still fail this test, because that literature was never the thing under review.
FDA's specific objections
FDA weighs four criteria: whether the substance is well characterised physically and chemically, whether it has been used historically in compounding, what evidence exists on effectiveness, and what safety issues its use in compounding raises. Here is where Semax landed on each.
FDA says neither form is well characterised, citing missing endotoxin data for the injectable routes and no information showing how an appropriate container and pump for an intranasal spray product would be selected and qualified.
FDA describes the available references as limited by small sample size and missing clinical endpoints — and says some demonstrated a lack of effectiveness. It concluded the evidence is insufficient to support semax for cerebral ischemia, migraine or trigeminal neuralgia, all of which it notes are serious conditions with approved therapies available.
FDA says there is a lack of information on the safety profile and that compounding use may raise safety concerns, and that it did not identify information addressing immunogenicity risk.
What is specific to Semax
Six of the seven objections above could be written about almost any of the compounds on the July agenda. These next points could not — they are what makes this file different from the other six.
FDA cites direct evidence from studies in non-ischemic rats that semax has anticoagulant and antithrombotic properties — increased plasma anticoagulant and fibrinolytic activity, smaller thrombi, and roughly 35% reduced platelet aggregation. Because the study did not establish a dose-response relationship, FDA says it is unclear whether doses could be titrated to reverse a hypercoagulating state without creating conditions favouring a bleeding event. This is a pharmacological effect on clotting in a substance marketed for cognition.
In mice, semax potentiated amphetamine-induced dopamine release in the striatum and amphetamine-induced locomotor activity. FDA calls this concerning, noting that increased striatal dopaminergic tone is a response typically induced by drugs of abuse such as cocaine. It adds that it found no nonclinical study assessing abuse potential by the proposed subcutaneous route.
Semax is an approved medicine in Russia. It is not FDA-approved, and FDA's briefing states it is not a component of any FDA-approved drug. Approval in another jurisdiction is not a US regulatory status and carries no weight in a 503A Bulks List decision.
The evidence picture
Grey Peptides grades semax's evidence base as medium — the highest of the seven, and still short of the bar. That grade reflects a real Russian clinical literature. FDA's reading of that same literature is that it is small, methodologically limited, and in places negative.
Two readings of the same file are worth separating. FDA's conclusion is about a regulatory question — whether the record supports letting pharmacists compound this substance for this use. That is a higher bar than "there is some interesting science here," and a lower bar than "this substance is harmful." Almost everything FDA said about Semax is a statement about missing information, not a finding of harm. Reporting that as "FDA says Semax is dangerous" is wrong. So is reporting it as "FDA found no safety problems."
Where this sits in our encyclopedia
Our entry on this compound covers the underlying pharmacology, the published literature, and the status picture independent of this meeting. The two are separate reads: the encyclopedia entry is about the compound, and this page is about the regulatory file.
Mechanism, evidence grade, half-life, approval status, and sources. PCAC July 2026 — the full picture
All seven compounds, what the vote does and doesn't change, and what to watch. Peptide Regulatory Status Tracker
Category 1/2/3, 503A vs 503B, and where every peptide sits.
The other six compounds
BPC-157 · KPV · TB-500 · MOTS-c · Emideltide (DSIP) · Epitalon
FDA — July 23–24, 2026 Meeting of the Pharmacy Compounding Advisory Committee ↗
FDA briefing documents released June 29, 2026. Federal Register notice 91 FR 20465, published April 16, 2026 (FR Doc. 2026-07361), Docket No. FDA-2025-N-6895. FDA Briefing Document for Semax (free base) and semax acetate, released June 29, 2026.