The Semax discussion brought together the central issues running throughout the two-day PCAC meeting: what evidentiary standard applies under Section 503A, how much weight should be given to foreign clinical use and physician experience, whether FDA’s presentation reflected the complete record before the Committee, and whether unresolved quality concerns support exclusion or a more controlled pathway.
Semax is a synthetic seven-amino-acid peptide derived from the ACTH 4–10 fragment. It was designed to retain certain neurological activity without the hormonal effects of full-length ACTH. The nominations proposed intranasal products and, in one instance, subcutaneous administration for cerebral ischemia, migraine, and trigeminal neuralgia.
Semax had a broader clinical history than FDA’s presentation reflected
Semax is registered in Russia as 0.1% and 1% nasal drops. Public commenters described more than 30 years of reported use in Russia and Ukraine, along with foreign studies involving stroke, neurological recovery, cognition, and related conditions.
FDA reviewed their own limited human evidence and concluded that it was insufficient to support effectiveness. For cerebral ischemia, the agency relied largely on an abstract that lacked complete information concerning dose, route, treatment duration, concurrent therapies, and clinical outcomes. For migraine and trigeminal neuralgia, FDA reviewed one small, uncontrolled study involving a single intranasal dose. Four of 12 migraine patients reported complete headache relief, while the remaining eight reported reduced but persistent pain. FDA emphasized that the study lacked blinding, a control group, sufficient baseline characterization, and validated outcome measures. Semax did not resolve pain for most patients with trigeminal neuralgia.
The Committee directly questioned the limits of FDA’s review. FDA acknowledged that several Russian-language publications had not been fully evaluated because some were available only as abstracts and others reportedly lacked English abstracts entirely. The information FDA accessed often omitted the route, dose, frequency, duration, study design, or details needed to assess the validity of the reported outcomes.
Public commenters stated that translated studies, certificates of analysis, draft monograph materials, and retrospective pharmacy information had been submitted through the public-comment process but were not fully reflected in FDA’s prepared analysis.
One commenter represented that a retrospective review covered more than 350,000 doses and that a separate search of emergency-department, hospital-admission, poison-control, and related data identified no Semax-associated adverse-events. Another reported more than 11,000 vials dispensed without a recorded complaint. This supported the argument that the human-exposure record was broader than FDA’s presentation suggested.
The intended clinical use remained unclear
Committee members pressed FDA on what “cerebral ischemia” meant in this context. Semax could theoretically be used during an acute stroke, to limit early ischemic injury, during post-stroke rehabilitation, or for broader neurological concerns. Those are materially different uses with different timing, dosing, efficacy, and safety questions.
FDA acknowledged that the available literature did not clearly establish when Semax was administered relative to the ischemic event, whether patients were receiving other therapies, or whether the proposed use was acute treatment or later recovery.
One Committee member also observed that Semax appears to be used more commonly in current practice for migraine, brain fog, cognitive support, and neuroinflammation than for acute cerebral ischemia. That raised a broader question about whether the uses evaluated by FDA captured the settings in which clinicians currently report using Semax.
FDA raised safety concerns, but several remained unresolved
FDA identified possible antithrombotic activity based on reported changes in blood-clotting markers. The agency stated that this could create a bleeding concern, particularly for patients taking anticoagulants or otherwise at elevated hemorrhagic risk.
Committee questioning made that issue more specific. A neurologist asked whether Semax could add to the bleeding risk associated with tissue plasminogen activator, or tPA, and other acute-stroke interventions. FDA said the available literature did not provide enough information about timing, concurrent treatment, or clinical outcomes to evaluate that interaction. The concern was therefore clinically plausible but not a documented Semax–tPA interaction.
Public commenters did not dismiss the issue. They argued that possible antithrombotic activity supported prescriber oversight, patient screening, labeling, and caution for patients taking anticoagulants rather than categorical exclusion.
FDA also raised a potential abuse-related concern based on nonclinical findings suggesting increased dopaminergic signaling. The agency noted that similar signaling can occur with drugs of abuse, but it did not identify studies directly evaluating Semax’s abuse potential, and the relevant dose-response and systemic-exposure relationships were unknown.
FDA further noted that it had not identified published clinical studies directly assessing immunogenicity. Public commenters responded that Semax is a relatively short peptide and cited decades of intranasal use without a reported hypersensitivity or anti-drug-antibody signal, while acknowledging that no formal anti-drug-antibody study had been published.
The single adverse-event referenced involved an unverified online product
FDA identified one report involving eye pain and burning after a consumer used 0.1% Semax nasal drops purchased online from an unknown source. The individual was hospitalized, and the symptoms reportedly persisted for at least one year. FDA treated the report as relevant safety information but could not establish the product’s source, composition, quality, or whether Semax caused the injury.
Supporters argued that an adverse event involving an unverified online product cannot be assumed to establish the safety profile of a properly characterized Semax preparation made under defined compounding standards. One commenter stated that the product “could have contained battery acid for all we know” because its sourcing and contents were unknown.
The point was not to dismiss the reported injury. It was to distinguish an unknown online product from a formulation produced through a licensed pharmacy using qualified ingredients, validated testing, and professional oversight.
The strongest concerns involved identity, stability, and nasal delivery
FDA found the nominations inconsistent as to whether Semax free base or Semax acetate had actually been nominated. The submissions described the free base, while the certificates of analysis referred to acetate but included identifiers associated with the free-base form.
FDA also emphasized that “Semax” is a common name rather than a recognized United States Adopted Name. USP separately identified a possible look-alike and sound-alike concern between Semax and semaxinib, an investigational tyrosine-kinase inhibitor.
The intranasal route created another set of quality questions. FDA explained that performance depends not only on the peptide, but also on the pump, container-closure system, spray-content uniformity, spray pattern, plume geometry, droplet-size distribution, microbial quality, and compatibility between the formulation and device.
Stability remained unresolved as well. FDA identified information reporting four-year stability for Semax free base at minus 20 degrees Celsius, while the submitted certificates of analysis recommended storing Semax acetate between 2 and 8 degrees Celsius. USP questioned how those bulk-storage conditions would translate into compounding (certainly not at minus 20 degrees Celsius), transportation, dispensing, room-temperature handling, and patient use.
Public commenters did not deny those concerns. They argued that they were addressable through exact molecular identity, validated nasal devices, stability testing, qualified API suppliers, independent potency and impurity testing, lot-level traceability, patient screening, and adverse-event reporting. One commenter described the delivery issue as a “solvable quality problem, not a reason to foreclose” a lawful pathway.
Committee members challenged parts of FDA’s presentation
FDA cited a 2018 criminal case involving a compounding pharmacy that unlawfully distributed several drugs, including Semax. One Committee member criticized the reference, comparing it to discouraging people from buying an F-150 because one owner received a speeding ticket.
FDA then clarified that the case was included only to establish that Semax had been compounded since at least 2018—not to suggest that Semax caused or contributed to the unlawful conduct.
The Committee also asked whether FDA returns to nominators when submissions are unclear. FDA said it has issued information requests but described the process as frustrating because the responses did not always resolve the identity or form of the nominated substance. FDA further emphasized that nominators may supplement their submissions at any time.
That discussion reinforced the importance of complete nominations. It also highlighted a separate process concern: Committee members were expected to consider the full docket, while FDA’s prepared presentation did not fully address translated studies and other materials submitted in preparation for the meeting.
The Committee ultimately recommended adding Semax free base
The Committee voted 8–5, with one abstention, to recommend adding Semax free base to the 503A Bulks List.
Members voting no focused on the limited preclinical and clinical evidence, unresolved safety questions, serious proposed indications, physical and chemical characterization, and solubility concerns. Some were also concerned that inclusion could be perceived as an endorsement and lead patients away from therapies supported by stronger evidence. One member stated that the Committee could not “skip the rigorous scientific studies” ordinarily needed before making a product available. Another member expressed frustration that the Committee had not received more of the efficacy information contained in the Russian literature but still concluded that the four-factor analysis weighed against inclusion.
Members voting yes applied a different lens. Several stated that all four Section 503A criteria had been met and emphasized that PCAC was not approving a finished drug or applying a Phase 1 or new-drug approval standard.
One physician member summarized that distinction directly: “We didn’t approve a drug. Nobody put a finished product on a shelf.”
The member stated that his clinical practice gives him substantial exposure to what is already occurring in the peptide market. From that perspective, patients do not stop seeking peptides when regulated access is unavailable. In that member’s view, patients instead turn to research-use-only or “physician-use-only” products that may lack reliable sterility testing, verifiable certificates of analysis, pharmacy oversight, or meaningful accountability.
He explained that he did not support patients watching influencer videos, clicking TikTok links, and receiving unknown vials from overseas. He supported access through licensed pharmacies, valid prescriptions, clinician evaluation, laboratory testing, and products tested for potency, sterility, and harmful impurities.
As he summarized: “We do not protect the patient by pushing them into the dark. We just lose the ability to help them.”
The same member expressed direct disappointment with the review process, stating that FDA’s presentation relied on “surface-level searches” while hundreds of pages of research submitted on time for the meeting went unaddressed. He described FDA’s scientists as highly qualified but underprepared for the breadth of the record before the Committee.
That concern was echoed more broadly during the Semax discussion. Committee members expressed frustration that translated foreign studies and other information in the docket were not fully evaluated or reflected in FDA’s presentation. One dissenting member likewise stated that he was frustrated the Committee had not received more of the efficacy information contained in the Russian literature. FDA acknowledged that it lacked full English-language versions of several publications and could assess some only through limited abstracts.
Other affirmative voters cited the complete docket, reported safety information, physician experience, and the need to preserve patient-specific access under professional supervision.
Several members nevertheless thanked FDA and emphasized that the disagreement concerned the applicable standard and interpretation of the record—not a lack of shared commitment to patient safety. The National Association of Boards of Pharmacy representative abstained, consistent with the organization’s position neither supporting nor opposing peptide inclusion.
What the vote reflects
The vote was not a finding that Semax is FDA approved, proven effective for stroke or migraine, or free from unresolved risk. It reflected a majority view that the four applicable Section 503A criteria had been met and that the limitations in the evidence should be considered alongside the realities of current patient demand and unregulated access.
The dissenting members believed the gaps in characterization, safety, effectiveness, and clinical application were too significant to support inclusion. The majority believed those uncertainties did not justify pushing patients toward a gray market with fewer controls and less professional oversight.
The Semax discussion also exposed a broader process concern. Committee members were expected to evaluate the complete docket, yet FDA’s prepared analysis did not fully address translated studies and other information submitted for the meeting. For several members, that disconnect made the available evidence appear narrower than the record actually before the Committee.
The 8–5 recommendation ultimately reflected not only differing views of Semax, but differing views of PCAC’s role: whether uncertainty requires exclusion, or whether Section 503A permits supervised, patient-specific access while stronger quality controls and better safety data continue to develop.