Semax: An ACTH(4-7)-Derived Heptapeptide and Melanocortin Receptor Modulator

This content is provided by Superpower Health for educational and informational purposes only. Semax is not FDA-approved for any indication in the United States and is not available through Superpower. This page is not a substitute for medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider. For compound reference data, see the PubChem monograph for Semax (CID 68816).

The peptides with the deepest clinical data are often the least known outside their country of origin. Semax has been registered as a pharmaceutical in Russia since 1994, used in hospitals for ischemic stroke and cognitive decline, and studied in dozens of published trials. Yet it remains almost entirely absent from Western clinical awareness. That gap is not an accident of science. It is an artifact of language and geopolitics.

Here is what Semax is, what the published research actually shows, where the evidence base has real limits, and how to think about monitoring if you are considering it.

Key Takeaways

• Regulatory Status: Not FDA-approved in the United States. Registered with the Russian Ministry of Health in 1994 for cerebrovascular indications. As of April 2026, available in the US only through licensed 503A compounding pharmacies by prescription.
• Research Stage: Clinically studied in Russia for ischemic stroke, cognitive decline, and optic nerve disorders; limited independent Western replication; available through compounding.
• Availability: Not available through Superpower. Access, where available in the US, is through licensed 503A compounding pharmacies under a patient-specific prescription from a licensed provider.
• Prescribing information: View compound reference data (PubChem CID 68816)
• How it works: Binds melanocortin receptors and upregulates BDNF and NGF expression in the hippocampus and cortex.
• What the research shows: In a 110-patient non-randomized Russian clinical trial by Gusev, Martynov, and colleagues published in 2018 in Zhurnal Nevrologii i Psikhiatrii (43 men, 67 women; mean age 58.0 ± 9.7 years), Semax (6,000 mcg/day intranasally in two 10-day courses separated by a 20-day interval) elevated plasma BDNF and improved Barthel index and MRC motor-scale scores over a ~5-month observation period in both early-rehabilitation (89 ± 9 days post-stroke) and late-rehabilitation (214 ± 22 days post-stroke) subgroups versus comparator subgroups not receiving Semax. Numerical effect sizes, confidence intervals, and p-values were not reported in the published abstract, and the trial was neither randomized nor placebo-controlled — a meaningful limitation on the strength of the finding.

What Is Semax?

Semax is a synthetic heptapeptide with the amino acid sequence Met-Glu-His-Phe-Pro-Gly-Pro. It is an analog of the ACTH(4-7) fragment, which is the four-residue core that carries the central nervous system activity of adrenocorticotropic hormone, extended with a C-terminal Pro-Gly-Pro sequence that stabilizes the molecule against enzymatic degradation. This structural modification is what makes Semax viable as a pharmaceutical. The parent ACTH(4-7) fragment is rapidly cleaved in biological tissues, while the Pro-Gly-Pro extension extends its half-life sufficiently for nasal administration to achieve CNS activity.

Semax was developed in the 1980s at the Institute of Molecular Genetics in Moscow by a research group led by Igor Ashmarin. The heptapeptide was designed to retain the cognitive-modulating properties of ACTH fragments without the steroidal and adrenal effects of full-length ACTH. An early human EEG study by Koroleva, Meizerov, and colleagues, published in Bulletin of Experimental Biology and Medicine in 1996, established measurable CNS electrophysiological activity of Semax in humans and provided foundational evidence underpinning its subsequent regulatory approval. Semax is delivered intranasally, typically as a 0.1% or 1% aqueous solution, and is designed to cross the nasal mucosa and reach the brain through olfactory pathways. A 2010 study by Manchenko, Glazova, and colleagues published in Rossiiskii Fiziologicheskii Zhurnal im. I.M. Sechenova compared nootropic and analgesic effects of Semax across intraperitoneal and intranasal routes, providing the closest available reference on route-dependent activity. Direct pharmacokinetic data confirming blood-brain barrier penetration in humans is limited; the CNS effects are inferred from functional and neuroimaging studies rather than PK measurements.

What the Published Research Reports

The evidence base for Semax is dominated by research from Russian institutions, particularly the Institute of Molecular Genetics RAS and the Research Center of Neurology. Most published trials appear in Russian-language journals. Independent Western replication of the large clinical findings is essentially absent. The claims below are presented with that caveat explicitly in place: what Russian clinical research suggests, not what has been established through the Western trial standards used to evaluate FDA-approved compounds.

1. Neurotrophin upregulation and BDNF expression

The most mechanistically robust finding in the Semax literature is its effect on neurotrophins. Research by Dolotov, Karpenko, and colleagues published in Brain Research in 2006 showed that intranasal Semax produced a maximal 1.4-fold increase in BDNF protein and increased TrkB phosphorylation in the rat hippocampus, demonstrating engagement of the BDNF–TrkB signaling axis. A companion paper by Dolotov and colleagues in Journal of Neurochemistry the same year demonstrated that Semax binds specifically in the rat basal forebrain and that intranasal dosing at 50 and 250 mcg/kg produced a rapid increase in BDNF protein within 3 hours, providing protein-level (not just mRNA) confirmation of the effect. Agapova, Agniullin, and colleagues published a whole-brain neurotrophin gene expression study in Neuroscience Letters in 2007 showing Semax induces rapid, region-specific changes in BDNF and NGF transcript levels in the normal rat brain. Earlier in vitro work by Shadrina, Dolotov, and colleagues in 2001, published in Neuroscience Letters, demonstrated rapid induction of neurotrophin mRNAs in rat glial cell cultures following Semax exposure — the foundational ACTH-analog neurotrophic signaling paper. In the clinical setting, a 2018 non-randomized open-label study by Gusev, Martynov, and colleagues in Zhurnal Nevrologii i Psikhiatrii in 110 post-stroke patients (43 men, 67 women; mean age 58.0 ± 9.7 years) found that Semax at 6,000 mcg/day intranasally — delivered as two 10-day courses separated by a 20-day interval — increased measurable plasma BDNF alongside improvements on the Barthel index and MRC motor scale over a ~5-month observation period, though effect sizes, confidence intervals, and p-values were not reported in the published abstract and the absence of randomization and placebo control limits causal inference. BDNF (brain-derived neurotrophic factor) supports neuronal survival, synaptic plasticity, and learning-associated hippocampal processes, making this the mechanistic through-line most relevant to Semax's cognitive effects.

2. The Russian ischemic-stroke trial program

The strongest clinical evidence for Semax comes from Russian stroke trials conducted by the Gusev group. An early clinical and electrophysiological study by Gusev and colleagues, published in Zhurnal Nevrologii i Psikhiatrii in 1997, compared 30 patients with acute hemispheric ischemic stroke receiving Semax (12 mg/day for moderate strokes or 18 mg/day for severe strokes, administered for 5–10 days) alongside combined intensive therapy against 80 patients with strokes of analogous severity receiving conventional therapy alone. The authors reported that Semax addition influenced the rate of recovery of general cerebral and focal — especially motor — deficits assessed by clinical rating scales, EEG mapping, and somatosensory evoked potentials. Numerical effect sizes and p-values were not reported in the published abstract, and the non-randomized allocation limits causal interpretation; this study is the anchor citation for the 1990s Russian regulatory approval of Semax for acute ischemic stroke. A follow-up Gusev-group comparative study published in 2005 examined Semax in 187 patients across different stages of chronic cerebrovascular insufficiency, reporting clinical improvement, stabilization of disease progression, reduced risk of stroke and transient ischemic attacks, and good tolerability including in older age groups. Specific dose, duration, effect sizes, and p-values were not reported in the published abstract — a meaningful limitation on interpretability — but the trial extended the Russian-context indication beyond acute stroke. The 2018 Gusev et al. trial above — the best-powered and most recently published Semax study on PubMed, though non-randomized and not placebo-controlled — enrolled 110 post-stroke patients receiving Semax at 6,000 mcg/day intranasally in two 10-day courses separated by a 20-day interval, and reported improvements on the Barthel index and MRC motor scale in early-rehabilitation (89 ± 9 days post-stroke) and late-rehabilitation (214 ± 22 days post-stroke) subgroups over a ~5-month observation period, alongside the BDNF elevation noted above; numerical effect sizes and p-values were not reported in the published abstract. A comparative time-course study by Shadrina, Kolomin, and colleagues in 2010, published in the Journal of Molecular Neuroscience, characterized NGF and BDNF gene expression in rat hippocampus, frontal cortex, and retina under Semax, and a 2010 paper by Dmitrieva, Povarova, and colleagues in Cellular and Molecular Neurobiology showed that Semax and its C-terminal Pro-Gly-Pro fragment activate neurotrophin and receptor transcription after cerebral ischemia, directly linking the BDNF and NGF mechanism to the stroke indication. Genome-wide transcriptional analyses by Medvedeva, Dmitrieva, and colleagues published in BMC Genomics in 2014 and in Molecular Genetics and Genomics in 2017 characterize Semax's neuroprotective profile at the gene expression level, showing modulation of immune-response and vascular-system gene expression in focal brain ischemia models. Transcriptome and proteome analyses by Filippenkov, Stavchansky, and colleagues published in Genes in 2020 and by Sudarkina, Filippenkov, and colleagues in the International Journal of Molecular Sciences in 2021 confirmed Semax's protective signature following cerebral ischemia-reperfusion in rodent models. These are mechanistic studies, not clinical outcome data, but they provide a molecular basis for the functional findings in the clinical trials.

3. Default mode network activity in healthy volunteers

A 2018 placebo-controlled study by Lebedeva, Panikratova, and colleagues, published in Bulletin of Experimental Biology and Medicine, used resting-state functional MRI in 24 healthy volunteers (11 men, 13 women; mean age 43.9 ± 9.5 years; n = 14 receiving a single intranasal dose of 1% Semax, n = 10 placebo) across three imaging sessions (baseline, 5 minutes, and 20 minutes post-dose) and found a greater volume of the rostral medial-frontal-cortex subcomponent of the default mode network in the Semax group than in controls. The abstract does not report numerical effect sizes, confidence intervals, or p-values, and the single-dose design and small n limit the strength of the finding. The study was small but is one of the more methodologically rigorous modern references in the Semax literature, providing imaging-level support for the cognitive and attentional effects reported anecdotally and in less controlled settings. The default mode network is associated with self-referential processing, memory consolidation, and the background cognitive activity that underlies sustained focus. The imaging findings do not establish a specific clinical outcome, but they confirm that Semax produces detectable functional changes in healthy human brains at the neuroimaging level.

4. Stress-model preclinical findings

Preclinical data suggest Semax has stress-modulating properties. A 2013 study by Yatsenko, Glazova, and colleagues published in Doklady Biological Sciences demonstrated that the heptapeptide Semax attenuated behavioral effects of chronic unpredictable stress in rats. A more recent paper by Inozemtseva, Yatsenko, and colleagues, published in European Journal of Pharmacology in 2024, reported that Semax reversed or substantially attenuated chronic-unpredictable-stress-induced anhedonia, body-weight-gain suppression, adrenal hypertrophy, and hippocampal BDNF reduction in male rats. Notably, this paper appears in an Elsevier journal, making it one of the few post-2020 Western-indexed validations of the stress and mood mechanism. These findings are preclinical and cannot be directly extrapolated to human antidepressant efficacy. The mechanism likely involves Semax's modulatory effects on dopamine and serotonin neurotransmission, as well as its BDNF upregulation, which is a shared mechanism with established antidepressant treatments. The evidence does not support framing Semax as a treatment for depression or anxiety disorders.

5. Optic nerve and retinal research

Russian clinical practice has included Semax in ophthalmological applications, particularly for optic nerve disease. A 2004 study in Vestnik Oftalmologii by Sheremet, Polunin, and colleagues provided experimental substantiation for Semax as a neuroprotector in optic nerve disorders. The mechanism parallels its CNS neuroprotective effects: BDNF and NGF upregulation in retinal tissue, consistent with findings by Shadrina and colleagues showing Semax-induced neurotrophin expression changes in the rat retina alongside hippocampus and frontal cortex. This indication is predominantly relevant in the Russian clinical context and is less established by the standards Western regulatory bodies would require for approval.

6. Hypothesis-level mentions in the broader literature

A 2007 hypothesis paper by Tsai, published in Medical Hypotheses, proposed Semax as a candidate compound for attention-deficit/hyperactivity disorder and Rett syndrome, drawing on its dopaminergic and BDNF-upregulating properties. This is hypothesis-grade evidence. No controlled clinical trial of Semax in ADHD has been published to date. The reference is included here for completeness because it appears in the English-language PubMed literature and reflects a real mechanistic rationale, not because it constitutes clinical evidence for efficacy.

Semax vs. Selank: Key Differences

Semax and Selank are the two most frequently discussed neuropeptides developed at the Institute of Molecular Genetics in Moscow, and they are commonly compared because they share an origin and are sometimes described as companion compounds. The single most important functional difference is this: Semax has been studied primarily for cognitive and neuroprotective effects, while Selank has been studied primarily for anxiolytic and stress-modulating effects. This distinction reflects different receptor pharmacologies and different clinical applications.

Semax modulates melanocortin receptors (primarily MC4R) and drives BDNF upregulation. Its clinical applications have centered on stroke recovery, cognitive enhancement, and neuroprotection under conditions of neural injury. Selank is a heptapeptide analog of the endogenous tetrapeptide tuftsin; its mechanism involves modulation of GABA-A receptor activity and enkephalin metabolism, which produces its anxiolytic profile. Selank has been studied in Russia for generalized anxiety disorder, while Semax has not been shown to have meaningful anxiolytic activity in the clinical literature. In terms of evidence quality, both compounds share the same limitation: the strongest data come from Russian-language trials with limited independent replication. Neither compound has been evaluated in a randomized controlled trial conducted under Western regulatory standards for any clinical indication.

Biomarkers Relevant to Understanding Cognitive and Metabolic Baseline

Semax does not directly shift the standard Superpower biomarker panel in a way that allows for straightforward target-engagement monitoring. Plasma BDNF, which increased in the 2018 Gusev et al. clinical trial, is not a routine clinical assay. The monitoring approach is therefore primarily safety-oriented, supplemented by disease-specific markers relevant to the individual member's reason for use. The following markers are worth establishing at baseline and monitoring during use.

• Complete blood count (CBC): General safety baseline. Semax does not carry a specific hematologic warning, but a baseline CBC is appropriate before any prescription compound. It flags pre-existing conditions that could interact with the physiological effects of peptide administration.
• Comprehensive metabolic panel (CMP): Covers liver and kidney function, electrolytes, and glucose. Relevant for monitoring general safety during use of any prescription compound, including Semax. Provides a reference point if any tolerability concerns arise during a course.
• Cortisol: Semax is an ACTH-fragment analog. The heptapeptide does not carry the same adrenocortical activity as full-length ACTH and is not expected to meaningfully suppress or stimulate the HPA axis at therapeutic doses. A baseline cortisol reading is nonetheless prudent in any individual with a history of adrenal or hypothalamic-pituitary axis concerns. Providers may wish to recheck cortisol if the individual develops fatigue, mood changes, or other symptoms consistent with HPA dysregulation during or after a course.
• Thyroid-stimulating hormone (TSH) and free T3: Cognitive symptoms including brain fog, poor memory, and attentional difficulties are common presentations of subclinical thyroid dysfunction. Establishing thyroid status before attributing cognitive changes to Semax use (or lack thereof) is clinically meaningful. For members presenting primarily with cognitive concerns, a broader neurotransmitter and cognitive longevity panel that includes thyroid markers provides useful context.
• hs-CRP (high-sensitivity C-reactive protein): Systemic inflammation is a common driver of cognitive impairment, fatigue, and poor stress resilience. Baseline hs-CRP establishes whether inflammatory load may be contributing to the symptoms that prompted consideration of Semax. Members whose primary concern is mental clarity and focus benefit from ruling out inflammatory contributors before adding a peptide compound.
• Fasting glucose and hemoglobin A1c (HbA1c): Metabolic dysregulation, including insulin resistance and elevated blood glucose, directly impairs cognitive function and neuroplasticity. These markers establish metabolic status as context for cognitive concerns and as a safety baseline before any prescription compound use.
• Vitamin B12 and folate: B12 deficiency is among the most common and correctable causes of cognitive decline and mood disruption. Ruling out deficiency before starting Semax ensures that any response, or lack of response, is not confounded by a nutritional gap that would respond to supplementation rather than a neuropeptide.

Who Should Not Use Semax

The short answer: no one, outside an IRB-approved clinical research study. Although Semax was registered by the Russian Ministry of Health in 1994 for cerebrovascular indications and has decades of Russian clinical use behind it, it is not FDA-approved in the United States, has not been submitted for FDA review, and has no completed Western randomized controlled trial. There is no US population for whom use of this compound is supported by FDA-reviewed evidence. US access exists only in a narrow 503A-compounded form at a provider's discretion, outside the normal FDA-approved drug pathway.

Several mechanistic considerations are of particular concern. These are illustrative — not a contraindication checklist, because there is no FDA-approved indication:

• Pregnancy or breastfeeding — no reproductive or developmental toxicology data exists
• History of or active seizure disorder — melanocortin receptor modulation carries theoretical CNS excitatory potential
• Active or suspected neuroendocrine malignancy — ACTH-fragment analogs carry theoretical concern in the setting of neuroendocrine pathology
• Known hypersensitivity to Semax or formulation components
• Hepatic or renal impairment — pharmacokinetics under compromised organ function are uncharacterized

Side Effects and Safety Considerations

The human safety data for Semax come almost exclusively from Russian clinical trials, primarily the Gusev group studies including the 2018 Gusev et al. trial. These studies consistently report a favorable tolerability profile at the doses studied, typically 0.1% to 1% intranasal solution at 6,000 mcg per day for 10-day courses. Long-term safety data, independent Western pharmacovigilance, and rigorous structured adverse-event reporting are not available. The following reflects what the published literature reports.

Common (reported in Russian clinical studies):

• Mild nasal irritation or tingling at the site of administration (intranasal delivery; typically transient)
• Transient headache following administration (reported infrequently; usually resolves without intervention)
• Mild fatigue or drowsiness in some individuals following initial dosing

Less common but reported or theoretically relevant:

• Irritability or mood changes (contact provider if persistent; may reflect HPA-axis modulation)
• Sleep disturbance (contact provider if it develops or worsens during a course)
• Appetite changes (reported anecdotally; not systematically characterized in published trials)

The absence of structured adverse-event reporting in the available literature means that the true incidence of less common effects is unknown. Independent Western pharmacovigilance data do not exist. Any novel or persistent symptom during a Semax course warrants contact with the prescribing provider. Because Semax's primary human safety data derive from 10-day treatment courses, the safety profile of extended or repeated courses is not established.

Is Semax Legal?

As of April 2026, Semax is not FDA-approved in the United States for any indication. It has not been submitted for FDA review. It is not available over the counter. In the United States, Semax is available only as a compounded preparation dispensed pursuant to a patient-specific prescription from a licensed provider through a licensed 503A compounding pharmacy.

In the Russian Federation, Semax is a registered pharmaceutical drug. It was approved by the Russian Ministry of Health in 1994 for cerebrovascular indications and has been used in Russian clinical settings for ischemic stroke, cognitive decline, and optic nerve disorders for more than three decades. This regulatory status in Russia does not confer FDA approval or equivalence in the United States and does not constitute evidence of safety or efficacy under FDA standards. As of April 2026, Semax is not included on the WADA Prohibited List; its use in sport contexts does not currently carry an anti-doping violation risk, though athletes subject to testing should confirm current status with their relevant governing body.

Understanding Your Baseline Before Starting Semax

Semax does not produce the kind of direct, measurable biomarker shift that makes response monitoring straightforward. You cannot track a Semax-specific lab value the way you track IGF-1 on sermorelin or testosterone on enclomiphene. What you can do is establish a clear picture of the variables most likely to explain your current cognitive state, then use that picture to contextualize what changes (or fails to change) during a course. TSH, hs-CRP, B12, fasting glucose, and a comprehensive metabolic panel together address the most common reversible contributors to cognitive symptoms. If those markers are normal and cognitive concerns persist, a provider has a cleaner rationale for considering a neuropeptide compound. Without that baseline, it is difficult to know what you are measuring or whether any change is attributable to Semax or to a confounding factor that testing would have identified first.

That discipline, test first then evaluate, reflects Superpower's approach to health intelligence: every clinical decision should be grounded in objective data, not assumptions about what the symptom picture means. Understanding where your biomarkers stand before starting any compound is what makes the clinical story readable afterward.

IMPORTANT SAFETY INFORMATION

Semax is NOT FDA-approved for any indication in the United States. Semax has not been submitted to the FDA for review. Semax is approved in the Russian Federation for cerebrovascular indications; this approval does not confer FDA approval or constitute evidence of safety or efficacy under FDA standards. In the United States, Semax is available only as a 503A compounded preparation dispensed pursuant to a patient-specific prescription from a licensed provider. Superpower Health does not prescribe, sell, compound, or facilitate access to Semax; this page is provided for educational and informational purposes only.

The evidence base for Semax consists predominantly of clinical and mechanistic studies conducted by Russian research institutions and published largely in Russian-language journals. Independent Western replication is essentially absent. The safety and efficacy of Semax have not been established through adequate and well-controlled clinical trials under FDA standards. Long-term safety data and independent pharmacovigilance data are not available.

Semax should not be used by anyone outside an IRB-approved clinical research study. Mechanistic considerations of particular relevance: pregnancy or breastfeeding (no reproductive/developmental data); history of or active seizure disorder (theoretical CNS excitatory potential); active or suspected neuroendocrine malignancy (theoretical concern given ACTH-fragment lineage); known hypersensitivity to Semax or formulation components; hepatic or renal impairment.

Warnings: mood changes or irritability (contact provider if persistent); sleep disturbance (contact provider if it develops or worsens); nasal mucosal irritation with repeated intranasal administration; HPA axis considerations in individuals with known adrenal or pituitary pathology. The safety profile of extended or repeated courses beyond published 10-day protocols has not been established.

Common side effects: nasal irritation, transient headache, mild fatigue after initial dosing.

As of April 2026, Semax is not included on the WADA Prohibited List. Athletes subject to anti-doping testing should verify current status with their governing body before use, as regulatory classifications are subject to change.

Compound reference data: PubChem CID 68816.