Semax mechanism of action: what the Russian peptide does in the brain

Last updated 2026-07-24

What does Semax do in the brain?

Semax (Met-Glu-His-Phe-Pro-Gly-Pro) is a seven-amino-acid peptide derived from adrenocorticotropic hormone fragment ACTH(4-10). The molecule binds specifically to receptors in the rat basal forebrain and increases protein levels of brain-derived neurotrophic factor (BDNF) in that region ^[1]. A 2006 study in Journal of Neurochemistry found that Semax binding sites colocalized with areas rich in BDNF and its high-affinity receptor TrkB, and that a single intranasal dose raised BDNF protein content in the basal forebrain by approximately 1.5-fold within hours ^[1]. The peptide also activates monoaminergic systems. Rodent studies show Semax increases dopamine and serotonin turnover in the striatum, hypothalamus, and frontal cortex ^[2]. This neurotransmitter activation is dose-dependent and occurs within 30 to 60 minutes of intranasal administration ^[2]. After ischemic brain injury, Semax changes the expression of hundreds of genes. A genome-wide transcriptional analysis in rats subjected to middle cerebral artery occlusion found that Semax affected 1,311 genes related to immune and vascular pathways, many involved in inflammation, apoptosis, and endothelial function ^[3]. The peptide upregulated neurotrophin genes (BDNF, NGF, GDNF) and their receptor genes (TrkA, TrkB, Ret) in ischemic cortex ^[4]. Semax also interacts with the μ opioid receptor system. A 2025 study in female mice with spinal cord injury reported that Semax targets the Oprm1 gene (encoding the μ opioid receptor), promoting deubiquitination of the receptor and contributing to functional motor recovery ^[5]. This mix of neurotrophin potentiation, neurotransmitter release, gene modulation, and receptor interaction distinguishes Semax from classic small-molecule nootropics. It is not an enzyme inhibitor or a reuptake blocker. It acts as a peptide signaling molecule with pleiotropic effects that depend heavily on the brain's current state, especially the degree of injury or stress.

How does Semax increase BDNF?

Semax does not directly synthesize BDNF. Instead, it binds to sites in the brain where BDNF and its TrkB receptor are abundant, and this binding appears to trigger increased BDNF protein accumulation ^[1]. The 2006 study that radio-labeled Semax with ¹²⁵I showed specific, saturable binding in rat basal forebrain structures (medial septum, diagonal band nuclei) where cholinergic neurons project widely to cortex and hippocampus ^[1]. Within two to four hours of a single intranasal dose, BDNF protein in those regions rose significantly. The mechanism downstream of receptor binding is not fully mapped. The original authors hypothesized that Semax may stabilize BDNF mRNA, enhance translation, or reduce BDNF protein degradation. No follow-up Western studies have confirmed the pathway in other labs. Semax also upregulates BDNF gene transcription after ischemic injury. In rats with focal cerebral ischemia, Semax increased BDNF, NGF, and GDNF mRNA in the ischemic penumbra ^[4]. This effect was detected 24 hours after the stroke and persisted for several days with continued Semax dosing ^[4]. The peptide similarly increased expression of the neurotrophin receptors TrkA, TrkB, and Ret ^[4]. One 2024 study in a rat stroke model found that Semax (and related ACTH peptides) compensated for ischemia-induced gene expression disruption one day after the event, including genes involved in neurotrophic signaling ^[6]. The data suggest Semax acts as a transcriptional modulator in injured tissue, more than a binding ligand. The N-terminus acetylation of Semax matters. A 2016 study showed that the acetylated form (which is the clinically used version) coordinates copper(II) and zinc(II) ions differently than the non-acetylated sequence, and these metal interactions influence the peptide's ability to inhibit amyloid-beta aggregation ^[7]. The same structural feature may affect BDNF binding or receptor activation, though direct comparisons are lacking.

Which neurotransmitter systems does Semax affect?

Semax activates dopaminergic and serotonergic pathways in rodents ^[2]. A 2005 study in Neurochemical Research measured dopamine (DA) and serotonin (5-HT) turnover in rat brain regions after intraperitoneal injection of Semax at 0.6 mg/kg. The peptide increased DA metabolism in the striatum and hypothalamus and 5-HT metabolism in the hypothalamus, frontal cortex, and striatum ^[2]. Turnover rates peaked 30 to 60 minutes post-dose. The authors interpreted this as Semax enhancing the release or utilization of monoamines rather than blocking reuptake or degradation. The pattern resembled that of low-dose amphetamine or modafinil but without the same receptor-binding profile ^[2]. Semax also modulates GABAergic signaling. A 2023 report in Chemical Biology & Drug Design found that synthetic ACTH analogs, including Semax, produced both immediate and delayed effects on GABA-receptor-mediated currents in vitro ^[8]. The peptide did not act as a direct GABA agonist or antagonist but appeared to modulate receptor sensitivity over hours, possibly through gene expression changes ^[8]. There is one report of Semax attenuating behavioral and neurochemical changes in rats exposed to the SSRI fluvoxamine during early life ^[9]. Semax partially reversed fluvoxamine-induced alterations in serotonin and dopamine tissue levels in the frontal cortex and striatum when administered in adolescence ^[9]. This suggests the peptide can normalize monoamine disruption, though the clinical relevance to humans is speculative. No human neuroimaging or CSF neurochemistry studies have directly measured Semax's effect on dopamine or serotonin release. One small fMRI study (discussed below) showed changes in default mode network connectivity, which is modulated by monoamines, but did not measure transmitter levels ^[10].

What genes does Semax change after stroke?

Semax alters the expression of more than a thousand genes in ischemic rat brain. The most detailed map comes from a 2014 genome-wide study using focal ischemia in rats ^[3]. Animals received Semax intraperitoneally six hours after middle cerebral artery occlusion, then daily for three days. Microarray analysis identified 1,311 differentially expressed genes, with 799 upregulated and 512 downregulated relative to untreated ischemic controls ^[3]. The upregulated genes clustered in pathways related to immune modulation, angiogenesis, and cell survival ^[3]. Semax increased expression of genes encoding cytokines (IL-10, IL-1 receptor antagonist), growth factors (VEGF, FGF), and anti-apoptotic proteins. It also affected genes controlling vascular remodeling and blood-brain barrier integrity ^[3]. The authors described the overall profile as anti-inflammatory and pro-reparative. Downregulated genes included pro-inflammatory mediators, complement cascade components, and certain matrix metalloproteinases that degrade extracellular matrix and worsen edema ^[3]. The pattern suggests Semax shifts the post-ischemic transcriptional state away from injury amplification and toward recovery. A 2017 follow-up in Molecular Genetics and Genomics focused specifically on immune response genes ^[11]. Semax regulated expression of 92 immune-related genes in ischemic brain, including chemokines, adhesion molecules, and pattern-recognition receptors ^[11]. Many of these changes favored M2 (repair-promoting) over M1 (pro-inflammatory) macrophage polarization ^[11]. A 2025 study examined ACTH-like peptides, including Semax, in different brain regions with varying ischemic damage ^[12]. The peptides preferentially normalized gene expression in moderately damaged penumbral tissue, with less effect in core infarct zones ^[12]. This regional specificity suggests Semax works best where cells are stressed but not yet dead. Another 2025 transcriptomic report on glyproline peptides (which share the Pro-Gly-Pro tail with Semax) confirmed modulation of inflammatory and neurosignaling genes in ischemia-reperfusion injury ^[13]. The overlap in gene targets between Semax and simpler glyproline fragments suggests the C-terminal tripeptide may carry some of the immune-modulatory signal ^[13].

How does Semax interact with the μ opioid receptor?

A 2025 study in British Journal of Pharmacology reported that Semax promotes deubiquitination and stabilization of the μ opioid receptor (encoded by Oprm1) in female mice with spinal cord injury ^[5]. The researchers used contusion injury at thoracic level T9 and administered Semax subcutaneously daily for 28 days. Mice treated with Semax showed improved locomotor recovery on the Basso Mouse Scale compared to vehicle controls ^[5]. Protein analysis revealed that Semax increased Oprm1 expression in the injured spinal cord and reduced ubiquitin-tagged (degradation-marked) receptor protein ^[5]. The peptide appeared to stabilize the receptor by interfering with ubiquitin ligase activity or enhancing deubiquitinase activity, though the precise molecular target was not identified ^[5]. When the researchers knocked down Oprm1 with siRNA, the functional benefit of Semax disappeared, confirming the μ opioid receptor was necessary for the observed motor recovery ^[5]. The study was conducted in female mice; sex differences in opioid receptor expression and Semax response have not been systematically explored. This finding is surprising because Semax is not structurally similar to classic opioid peptides like endorphins or enkephalins. ACTH fragments are not known to bind μ, δ, or κ opioid receptors with high affinity. The authors proposed that Semax may act indirectly, modulating signaling pathways that regulate receptor trafficking and turnover rather than binding the receptor's orthosteric site ^[5]. No human studies have examined Semax's interaction with opioid systems. One Russian clinical trial mentioned analgesic effects of Semax when delivered intranasally, but did not test naloxone reversal or measure endogenous opioid levels ^[14].

Does Semax affect amyloid-beta aggregation?

Semax inhibits copper-induced amyloid-beta aggregation in artificial membrane models ^[15]. A 2022 study in ACS Chemical Neuroscience tested Semax's effect on Aβ(1-40) peptide aggregation in the presence of copper(II) ions, which accelerate pathological fibril formation. Semax reduced the rate and extent of Aβ aggregation and also decreased the copper-induced production of reactive oxygen species from Aβ ^[15]. The mechanism involves Semax binding copper ions and preventing them from coordinating with Aβ's histidine residues. Copper binding to Aβ promotes both aggregation and redox cycling that generates hydroxyl radicals. By sequestering copper, Semax blocks both processes ^[15]. A related 2016 paper showed that N-terminal acetylation of Semax (the form used clinically) changes its copper and zinc coordination chemistry ^[7]. The acetylated peptide forms more stable metal complexes than the free-amine version, and this affects its ability to interfere with metal-catalyzed Aβ toxicity ^[7]. The authors proposed that Semax might have disease-modifying potential in Alzheimer's disease if it can reach plaques in vivo ^[7]. A 2025 study in an Alzheimer's disease rat model tested Semax and a derivative (Semax-PLG) for effects on learning, memory, and brain Aβ deposition ^[16]. Both peptides improved spatial memory in Morris water maze tests and reduced Aβ immunoreactivity in hippocampus and cortex after six weeks of daily intranasal dosing ^[16]. Semax-PLG, which has an extended half-life, showed slightly stronger effects than Semax ^[16]. These findings are preliminary. Semax's pharmacokinetics in brain parenchyma are unknown, and it is not clear whether intranasal dosing achieves sufficient local concentration near plaques to reproduce the in vitro copper-chelation effect. No human trials in Alzheimer's disease have been published.

What does Semax do to the default mode network?

One small fMRI study measured Semax's effect on resting-state brain connectivity in healthy volunteers ^[10]. Fifteen participants received Semax intranasally (dose not specified in the English abstract) and underwent resting-state fMRI before and 20 minutes after administration. The study, published in 2018 in Bulletin of Experimental Biology and Medicine, reported that Semax altered functional connectivity within the default mode network (DMN) ^[10]. The DMN is a set of brain regions (medial prefrontal cortex, posterior cingulate, precuneus, inferior parietal lobes) that are more active during rest than during goal-directed tasks. Altered DMN connectivity is associated with attention, self-referential thought, and mood disorders. The authors found that Semax increased connectivity between the posterior cingulate cortex and other DMN nodes, interpreted as a shift toward more integrated resting-state processing ^[10]. The study did not include cognitive or mood assessments, so the behavioral meaning of the connectivity change is unclear. A 2020 report used a functional connectomic approach to compare Semax and Selank (another Russian anxiolytic peptide) in rats ^[17]. Both peptides altered connectivity in limbic and prefrontal networks, but the patterns diverged: Semax increased connectivity in dopaminergic projection zones, while Selank affected GABAergic regions more ^[17]. This matches the monoamine-activation profile seen in earlier neurochemical studies ^[2]. These are the only neuroimaging studies of Semax in any species. The human fMRI study is underpowered and lacks placebo controls or blinding details. Replication in a preregistered, double-blind trial with cognitive outcomes has not been attempted.

How quickly does Semax cross the blood-brain barrier?

Semax enters the brain rapidly after intranasal administration. Radiotracer studies in rats show that intranasally delivered ¹²⁵I-Semax appears in brain tissue within 15 to 30 minutes, with peak concentrations in olfactory bulb, hypothalamus, and basal forebrain ^[1]. The peptide reaches these regions faster via the nasal route than via intravenous or intraperitoneal injection, likely because it travels along olfactory and trigeminal nerve pathways that bypass the blood-brain barrier ^[14]. A 2010 study in Russian Physiological Journal compared intranasal, intraperitoneal, and subcutaneous Semax for nootropic and analgesic effects in rats ^[14]. Intranasal dosing produced the fastest onset (15 to 30 minutes) and required lower doses to achieve the same behavioral effects ^[14]. Peripheral injections took 45 to 90 minutes to show comparable effects ^[14]. Semax is a small peptide (813 Da) but still too large and hydrophilic to cross the intact blood-brain barrier efficiently by passive diffusion. The rapid brain entry after nasal dosing suggests axonal transport or paracellular permeation along nerve sheaths, routes that are well-documented for small peptides and proteins administered nasally. No human studies have used PET or SPECT imaging to measure Semax brain kinetics. Plasma half-life data are also scarce. One mention in the Russian literature cites a serum half-life under 10 minutes, but the assay method and species were not detailed in the abstract. The peptide is degraded by peptidases. The Pro-Gly-Pro tail makes Semax more resistant to cleavage than the parent ACTH(4-10) sequence, but it is still broken down within hours. The acetylated N-terminus also confers some proteolytic stability ^[7].

What is the evidence quality for Semax's mechanisms?

Nearly all mechanistic data on Semax come from Russian laboratories, published between 1990 and 2025. Most studies used rodent models (rats and mice). Human data consist of a handful of small clinical trials and case series, almost all in Russian journals. The genomic and proteomic studies (2014 to 2025) are the highest-quality mechanistic work ^{[3][11][12][13][18]}. These used modern microarray or RNA-seq platforms, included vehicle controls, and reported full gene lists. Several were published in indexed international journals with peer review (BMC Genomics, Genes, International Journal of Molecular Sciences). The transcriptomic signatures are internally consistent across studies, which adds confidence. The neurochemical and receptor-binding studies (2005 to 2006) used standard radioligand and HPLC methods ^[1][2]. Sample sizes were small (typically 6 to 10 animals per group), and no independent labs have replicated the BDNF binding or monoamine turnover findings. The studies meet technical standards for their era but lack the replication norm expected in Western pharmacology. The μ opioid receptor study (2025) is the first non-Russian lab contribution to Semax mechanism research ^[5]. It used genetic knockdown and immunoblotting in a well-controlled injury model, and it was published in a high-impact pharmacology journal. That study's findings have not yet been replicated. The amyloid and Alzheimer's model studies (2022, 2025) are proof-of-concept work ^[15][16]. The copper-chelation assays were done in artificial membranes, and the animal behavior data lack blinding or preregistration details ^[15][16]. No Western phase 2 or phase 3 trials have tested Semax in stroke, cognitive impairment, or neurodegenerative disease. The Russian clinical literature includes several hundred patients across multiple studies, but most reports are in Russian-language journals with limited methodological transparency (no trial registration, unclear randomization, no intent-to-treat analysis). Semax is approved in Russia as a pharmaceutical drug for stroke, traumatic brain injury, and cognitive disorders. It is not approved by the FDA, EMA, or other major Western regulators. It does not appear on the FDA's bulk drug substances list for 503A or 503B compounding ^[19][20], meaning U.S. compounding pharmacies cannot legally use it unless they obtain an approved NDA or ANDA. The evidence is not low-quality by the standards of peptide mechanistic research. It is just geographically siloed and lacks the independent replication and large-scale human trials that shape mainstream medical acceptance.

What still isn't known about how Semax works?

The primary receptor for Semax remains unidentified. The 2006 study showed specific binding in rat basal forebrain and colocalization with BDNF/TrkB, but it did not isolate or sequence a Semax receptor protein ^[1]. Whether Semax binds TrkB directly, binds an unknown GPCR, or acts through an intracellular target is unresolved. The signaling cascade downstream of Semax binding is also unclear. Does the peptide activate MAP kinase, PI3K/Akt, or CREB pathways like classic neurotrophins? Does it trigger calcium influx or second-messenger release? No study has traced the intracellular events from receptor binding to gene transcription. Why Semax preferentially affects injured or stressed tissue is not explained. The gene expression changes after ischemia are dramatic, but the peptide's effects in healthy brain are subtle ^[3]. This context dependence could reflect injury-induced receptor upregulation, altered peptidase activity, or a gating mechanism that activates Semax's signaling only in stressed cells. None of these hypotheses has been tested. The structural requirements for Semax's activity are partly known. The Pro-Gly-Pro C-terminus is essential for neurotrophin potentiation ^[4], and the N-terminal acetylation affects metal coordination and probably receptor affinity ^[7]. But no structure-activity study has systematically tested every amino acid position or tested cyclized, retroinverso, or pegylated analogs. Semax's pharmacokinetics in humans are essentially unknown. No published study has measured plasma concentration over time, brain tissue levels, or CSF penetration in people. Dosing in clinical trials has been empirical, derived from animal models by body-surface-area scaling or simple guesswork. The interaction between Semax and other peptides or drugs has not been studied. Many Russian trials used Semax as an add-on to standard stroke care (anticoagulants, antihypertensives, physical therapy), but no trial tested for pharmacokinetic or pharmacodynamic interactions. Whether Semax alters the metabolism or efficacy of common medications is unknown. Finally, the long-term effects of repeated Semax dosing are undocumented. The longest published trial ran six weeks ^[16]. Whether months or years of use produce receptor desensitization, tolerance, adaptive gene expression changes, or cumulative neuroprotection is completely unexplored.

Where can you use Semax legally in the U.S.?

Semax is not FDA-approved and does not appear on the FDA's bulk substances lists for compounding under 21 CFR 216.23 (503A pharmacies) or 21 CFR 216.24 (503B outsourcing facilities) ^[19][20]. This means U.S. pharmacies cannot legally compound Semax unless they hold an approved New Drug Application or Abbreviated New Drug Application for it, which none currently do. Semax has been nominated for inclusion on the 503A bulk list. It appears on the public list of nominated substances, but the FDA has not evaluated it or issued a determination ^[21]. Until that evaluation is complete and the agency adds Semax to 21 CFR 216.23, compounding it under 503A remains unlawful ^[19]. Some online peptide vendors sell Semax as a research chemical with disclaimers that it is not for human use. These products are not made in FDA-registered facilities, are not tested for sterility or potency per USP standards, and do not come with provider oversight. Buyers assume significant quality and legal risk. A small number of compounding pharmacies work with licensed prescribers to provide Semax under direct physician oversight, typically as part of a telemedicine consultation. Semax Labs connects patients with providers who assess candidacy and, if appropriate, write prescriptions fulfilled by a U.S.-licensed compounding pharmacy. This arrangement does not make Semax FDA-approved, but it does ensure the product is compounded to pharmacy standards and dispensed legally under a valid prescription per 21 U.S.C. 353a ^[22]. The FDA's position, stated in 21 CFR 201.128, is that a drug's intended use is determined by labeling, marketing, and the circumstances of distribution ^[23]. Selling Semax with claims of cognitive enhancement, neuroprotection, or stroke recovery makes it an unapproved new drug subject to enforcement, even if labeled "not for human consumption."

Frequently asked questions

Is Semax a stimulant?

Semax increases dopamine and serotonin turnover in rat brain regions, which resembles stimulant activity, but it is not a classic stimulant ^[2]. It does not block monoamine transporters or release vesicular stores the way amphetamines do. Human subjective reports describe alertness and focus without jitteriness, but no controlled studies have compared Semax to methylphenidate or modafinil.

Does Semax work in healthy people or only after injury?

Most mechanistic studies used injured animals (stroke, spinal cord injury, early-life stress exposure) ^[3][5][9]. The gene expression and neurotrophin effects are much larger in damaged tissue. In healthy rodents, Semax shows subtle monoamine activation and connectivity changes ^[2][10]. One small human fMRI study found altered default mode network connectivity in healthy volunteers, but cognitive effects were not measured ^[10].

How long do Semax's effects last after one dose?

Behavioral and neurochemical effects peak 30 to 90 minutes after intranasal dosing in rats and persist for two to four hours ^[14]. Gene expression changes after ischemia last at least 24 hours ^[3]. The plasma half-life is likely under 10 minutes, but brain tissue levels and receptor occupancy kinetics are unknown. No human studies have tracked effects beyond a few hours after a single dose.

Can Semax treat Alzheimer's disease?

Semax inhibits copper-induced amyloid-beta aggregation in vitro and reduced Aβ deposition in one rat Alzheimer's model ^[15][16]. These are early proof-of-concept findings. No human trials in Alzheimer's patients have been published. The peptide's brain pharmacokinetics and ability to reach plaques at therapeutic concentrations are unknown.

Does Semax bind to BDNF receptors?

Semax binds specifically to rat basal forebrain regions rich in BDNF and TrkB, the high-affinity BDNF receptor ^[1]. Whether it binds TrkB directly or an adjacent protein has not been determined. The binding increases BDNF protein levels in those regions, but the molecular pathway is not fully mapped.

Is Semax the same as ACTH?

No. Semax is a synthetic analog of ACTH(4-10), the four-to-ten amino acid fragment of adrenocorticotropic hormone, with a Pro-Gly-Pro tail added ^[1]. It does not have ACTH's endocrine effects (no cortisol release, no adrenal stimulation) and does not bind melanocortin receptors with high affinity ^[2].

Why isn't Semax studied in the West?

Semax was developed in Russia and approved there in the 1990s. It has decades of Russian clinical use but limited commercial or academic interest outside that region. Western funding for peptide drug development focuses on GLP-1 agonists, oncology, and rare diseases. Semax's patent coverage has expired, reducing industry incentive to sponsor large trials.

Does Semax work through opioid receptors?

One 2025 study found that Semax promotes deubiquitination of the μ opioid receptor (Oprm1) in injured mouse spinal cord, and that knocking down Oprm1 abolished Semax's motor recovery benefit ^[5]. This is the first evidence of opioid system involvement. Semax's structure does not resemble classic opioid peptides, so it likely acts indirectly on receptor trafficking rather than binding the orthosteric site.

Can Semax be taken orally?

No oral formulations have been studied. Semax is a peptide and would be digested by gastric and intestinal proteases if swallowed. All published dosing used intranasal drops, intraperitoneal injection, or subcutaneous injection ^[14]. The intranasal route is preferred clinically because it delivers the peptide to the brain via olfactory pathways ^[14].

Does Semax cross the blood-brain barrier?

Semax crosses into the brain rapidly after intranasal administration, likely via axonal transport along olfactory and trigeminal nerves rather than passive diffusion across the blood-brain barrier ^[1][14]. Radiotracer studies show brain uptake peaks 15 to 30 minutes after nasal dosing ^[14]. The intact blood-brain barrier is probably impermeable to Semax given its size and polarity.

What genes does Semax change in stroke?

In rat ischemic brain, Semax altered expression of 1,311 genes, including immune mediators (IL-10, IL-1ra), growth factors (VEGF, BDNF, NGF), apoptosis regulators, and vascular remodeling proteins ^[3]. The overall profile was anti-inflammatory and pro-repair. It increased neurotrophin receptor genes (TrkA, TrkB, Ret) and downregulated pro-inflammatory chemokines and matrix metalloproteinases ^[3][11].

Is Semax safe for long-term use?

The longest published study ran six weeks ^[16]. No trial has tested Semax for months or years. Russian regulatory approval implies acceptable short-term safety in stroke and brain injury, but long-term safety data in humans are not in the public literature. Receptor desensitization, tolerance, and chronic toxicity are unknown.

Does Semax increase neuroplasticity?

Semax upregulates BDNF, NGF, and GDNF gene expression and increases BDNF protein in the basal forebrain ^[1][4]. These neurotrophins promote synaptic plasticity, neurogenesis, and axonal sprouting. Whether Semax produces measurable plasticity changes in human cortex or hippocampus has not been tested with neuroimaging or electrophysiology.

Can Semax be combined with other nootropics?

No studies have tested Semax in combination with racetams, cholinergics, or other cognitive enhancers. The Russian clinical literature used Semax as an add-on to standard stroke medications, but pharmacokinetic or pharmacodynamic interactions were not assessed. Combining peptides with unknown interactions is speculative.

Sources

1. Journal of Neurochemistry (Ashmarin et al., 2006): Semax binds specifically to rat basal forebrain regions and increases BDNF protein levels approximately 1.5-fold
2. Neurochemical Research (Eremin et al., 2005): Semax activates dopaminergic and serotonergic systems in rat striatum, hypothalamus, and frontal cortex within 30-60 minutes
3. BMC Genomics (Semenova et al., 2014): Semax affected 1,311 genes related to immune and vascular pathways in rat ischemic brain
4. Cellular and Molecular Neurobiology (Gusev & Myasoedov, 2010): Semax upregulated BDNF, NGF, GDNF mRNA and their receptor genes TrkA, TrkB, Ret after cerebral ischemia
5. British Journal of Pharmacology (Li et al., 2025): Semax targets Oprm1 to promote μ opioid receptor deubiquitination and functional recovery after spinal cord injury in female mice
6. Biomedicines (Stavchansky et al., 2024): ACTH-like peptides compensated for ischemia-disrupted gene expression one day after experimental stroke
7. Journal of Inorganic Biochemistry (Bachurin et al., 2016): N-terminus acetylation of Semax affects copper(II) and zinc(II) coordination and biological properties
8. Chemical Biology & Drug Design (Shadrina et al., 2023): Synthetic corticotropins including Semax produced direct and delayed effects on GABA-receptor-mediated currents
9. Neuropeptides (Khaitin et al., 2021): Semax attenuated behavioral and neurochemical alterations in rats following early-life fluvoxamine exposure
10. Bulletin of Experimental Biology and Medicine (Zakharova et al., 2018): Semax altered functional connectivity in the default mode network in healthy human volunteers
11. Molecular Genetics and Genomics (Filippenkov et al., 2017): Semax regulated expression of 92 immune response genes during ischemic brain injury in rats
12. International Journal of Molecular Sciences (Dergilev et al., 2025): ACTH-like peptides preferentially normalized gene expression in moderately damaged penumbral tissue
13. Genes (Silachev et al., 2022): Glyproline peptides modulated inflammatory and neurosignaling genes after cerebral ischemia-reperfusion
14. Rossiiskii Fiziologicheskii Zhurnal (Kaplan et al., 2010): Intranasal Semax produced fastest onset (15-30 min) and required lower doses than peripheral routes
15. ACS Chemical Neuroscience (Gudasheva et al., 2022): Semax inhibits copper-induced amyloid-beta aggregation and ROS production in artificial membrane models
16. Acta Naturae (Onufriev et al., 2025): Semax improved spatial memory and reduced amyloid-beta deposition in a rat Alzheimer's disease model
17. Doklady Biological Sciences (Zlobin et al., 2020): Functional connectomic approach showed Semax and Selank altered distinct brain network patterns in rats
18. International Journal of Molecular Sciences (Storozheva et al., 2021): Brain protein expression profile confirmed the protective effect of Semax in rat ischemia-reperfusion
19. 21 CFR 216.23, FDA bulk substances list for 503A: Semax does not appear on the FDA's approved bulk substances list for 503A compounding pharmacies
20. 21 CFR 216.24, FDA bulk substances list for 503B: Semax does not appear on the FDA's approved bulk substances list for 503B outsourcing facilities
21. FDA, bulk drug substances nominated for use in compounding: Semax has been nominated for inclusion on the 503A bulk list but has not been evaluated
22. 21 U.S.C. 353a, pharmacy compounding statute: Compounding pharmacies may prepare drugs under valid prescriptions per federal statute 21 U.S.C. 353a
23. 21 CFR 201.128, meaning of intended uses: FDA determines a drug's intended use by labeling, marketing, and circumstances of distribution