Semax

Semax is a synthetic heptapeptide modeled on the active fragment of adrenocorticotropic hormone (ACTH), with a Pro-Gly-Pro tail attached to slow enzymatic breakdown ¹. In Russia it has been prescribed for decades as an intranasal drug for ischemic stroke, and it is now studied for cognitive support, stress adaptation, and neuroprotection in several research models ¹.

The consistent finding across studies is that Semax raises brain-derived neurotrophic factor (BDNF), a protein involved in neuron survival and learning-related plasticity, while normalizing many of the gene-expression changes produced by stroke, chronic stress, and inflammation ⁵. It also binds copper(II) and alters signaling at several receptors, including the NMDA glycine site and the mu-opioid receptor ¹¹.

Primary research areas

• Ischemic stroke: the strongest evidence, including human cohorts in both acute and recovery phases ¹.
• Cognition: older human nootropic and EEG studies plus extensive rodent data ⁴.
• Mood and stress: mostly animal models of chronic and acute stress ¹⁰.
• Eye neuroprotection: small human cohorts in glaucoma, optic neuropathy, and post-surgical retina ²¹.
• Alzheimer's disease: transgenic mouse and in vitro copper-amyloid work ¹².

Neurotrophin signaling and cholinergic support

Semax binds to specific, saturable binding sites in brain membranes, measured at a low nanomolar affinity in rat basal forebrain tissue ⁵. Within three hours of intranasal dosing, BDNF protein rises in this region, and systemic dosing raises BDNF across several brain areas ⁵. In cultured neurons, Semax increases survival of cholinergic neurons and stimulates the enzyme that makes acetylcholine, a neurotransmitter important for attention and memory ²⁵. It does not stimulate glial proliferation in these assays ²⁵.

Restoring disrupted gene expression

After experimental cerebral ischemia, Semax acts less like a single-receptor agonist and more like a transcriptomic normalizer: it suppresses ischemia-induced inflammatory genes (Il1a, Il1b, Il6, Ccl3, Cxcl2) and restores neurotransmission-related gene sets within about 24 hours ⁷. Protein-level findings match, with increased active CREB and reduced MMP-9, c-Fos, and active JNK ⁹.

Secondary mechanisms

Semax is a strong copper(II) binder. It removes copper from amyloid-beta complexes, blocks Fenton-type redox cycling, and reduces reactive oxygen species in cell models ¹³. Research has also linked Semax to mu-opioid receptor signaling in spinal cord injury ¹¹, and to reductions in the NMDA glycine-site receptor pool in some mouse strains ¹⁸. Rodent studies also report activation of dopaminergic and serotonergic brain systems ³⁶.

Human evidence

In ischemic stroke, Semax added to standard intensive therapy accelerated neurological recovery, particularly motor deficits, compared with historical controls ³. A 2024 Russian clinical review reports benefit in both acute and recovery phases, and in both atherothrombotic and cardioembolic stroke subtypes ¹. Small ophthalmology cohorts also report functional gains with 0.1% and 1% intranasal or electrophoresis protocols ²¹.

Cognitive and mood effects

The earliest human reports described nootropic-like activity ⁴, and EEG studies later showed changes after single doses ⁴³. In animal models, Semax reverses stress-induced anhedonia, weight-gain suppression, adrenal enlargement, and hippocampal BDNF loss in chronic unpredictable stress ¹⁰, and it prevents behavioral disruption after acute restraint stress ²⁰.

Neuroprotective and disease-model findings

• BDNF and cholinergic support: raises BDNF within hours and supports cholinergic neuron survival ⁵.
• Amyloid and copper: reduces amyloid inclusions and improves memory measures in transgenic Alzheimer mice ¹²; strips copper from amyloid-beta and silences metal-driven oxidative chemistry ¹³.
• Spinal cord injury: early evidence of neuroprotection through mu-opioid receptor signaling ¹¹.
• Confidence limits: human stroke cohorts are small and historically controlled; no placebo-randomized multinational trial has been published ¹. Mood evidence is preclinical rather than confirmed in human mood-disorder trials ¹⁰.

Clinical research uses Semax as ready-to-use intranasal solutions, most often 0.1% (1 mg/mL) and 1% (10 mg/mL) ¹. Stroke protocols deliver the higher concentration in the acute phase and then continue with 0.1% during rehabilitation (practitioner consensus) ¹. A 36-patient glaucoma cohort used 0.1% Semax for at least one month with no adverse reactions ²¹, and a 42-patient post-vitrectomy protocol used eight daily endonasal electrophoresis sessions with 1% Semax ²³.

Community research practice typically uses 100-600 mcg/day intranasally, divided into one to three administrations, in 10-30 day cycles. Injectable use is less supported: no human subcutaneous or intramuscular safety or efficacy data are published, and rodent intraperitoneal work spans roughly 50-450 mcg/kg ¹⁰.

Setting	Route	Dose	Frequency	Duration
Acute ischemic stroke	Intranasal	1% solution (practitioner consensus)	Multiple daily per clinical course (practitioner consensus)	Acute phase
Stroke recovery	Intranasal	0.1% solution (practitioner consensus)	Daily courses (practitioner consensus)	Through recovery
Glaucoma	Intranasal/endonasal	0.1% solution	Per ophthalmologic schedule	1 month or longer
Post-vitrectomy retina	Endonasal electrophoresis	1% solution	Daily	8 sessions
Chronic stress (rat)	Intraperitoneal	~49 mcg/kg (60 nmol/kg)	Daily	Weeks
Acute stress (rat)	Intraperitoneal	100 mcg/kg, 30 min prior	Single	Single

No formal human dose-response study has been published, so the human clinical dosing above is based on Russian treatment practice rather than titrated pharmacokinetic data ¹. Weight-scaled animal doses exist, but they are not direct evidence for human dosing.

Lyophilized Semax is water soluble and is typically reconstituted with bacteriostatic water or sterile 0.9% saline. In reported research practice, diluent is injected slowly against the vial wall and the vial is swirled gently, because vigorous shaking can damage the peptide. Clinical formulations are ready-to-use 0.1% and 1% intranasal solutions, which sidestep mixing altogether ¹.

Reconstituted Semax should be kept refrigerated at 2-8°C and is conventionally used within 30 days. Lyophilized powder can be stored long term at -20°C, protected from light and moisture. Repeated freezing and thawing of the reconstituted liquid is discouraged; the dry powder is more forgiving.

Stability is a real consideration because Semax is cleaved quickly by blood and tissue peptidases ³⁹, and the C-terminal Pro-Gly-Pro tail is part of what slows that breakdown ²⁶. Intranasal delivery still reaches brain and blood rapidly in animal studies ⁶, but the reconstituted solution should be discarded if cloudy or containing particles. The calculator below covers specific diluent volumes and concentrations.

Drug interaction data for Semax are almost entirely preclinical, so the signals below should be read as pharmacological caution rather than established human contraindications.

• Opioids. Semax inhibits enkephalin-degrading enzymes in human serum ⁵⁰ and attenuated opioid-induced analgesia in rats ⁵⁴. Direction may vary by pain test, and human interaction studies are absent.
• Stimulants. Semax activates dopaminergic and serotonergic brain systems in rodents ³⁶, and it strengthened d-amphetamine-induced dopamine release and locomotor activity in mice ⁵⁶. Additive stimulation is plausible, though not tested in humans.
• SSRIs and serotonergics. In young rats, Semax normalized brain monoamine and behavioral changes produced by early fluvoxamine exposure ³⁷. This appears normalizing rather than simply additive. No human serotonin-syndrome risk data exist; only rodent monoamine normalization has been published, so combined use with MAOIs or other serotonergic agents is uncharacterized.
• Glutamate-acting drugs. Semax reduced cortical NMDA glycine-site binding in mice and shifted mGluII receptor density in an attention-deficit model ¹⁷. The direction depends on strain and brain region.
• Anticoagulants and antiplatelets. Stress-model data show anticoagulant and antiplatelet activity ⁵², so additive bleeding risk is possible.
• Copper and zinc. Semax binds copper(II) with high affinity and also coordinates zinc ¹³. Wilson's disease and metal-chelating therapy deserve caution.
• Cardiovascular and autonomic effects. No published human cardiovascular or autonomic effects exist; only rodent heart-rate-variability data are available.

Semax is studied and prescribed in courses rather than as indefinite daily therapy. Published human examples include an eight-session post-vitrectomy course ²³, a one-month glaucoma add-on ²¹, and stroke treatment across distinct acute and recovery phases ¹.

Community research practice commonly uses 2-4 week courses followed by 1-4 week breaks, with 10-30 day intranasal cycles and 10-20 day injectable cycles in practitioner reports. Two or three consecutive cycles are sometimes described, followed by a longer break.

Mechanistically, the case for breaks rests on adaptation rather than documented toxicity. A single dose shifts a large cluster of genes in rat brain at 22.5 hours ³⁵, and repeated exposure changes NMDA glycine-site and mGluII receptor pools in rodent models ¹⁷. BDNF rises within hours of dosing ⁵, and community reporting describes a plateau in perceived cognitive benefit after 2-4 weeks, along with occasional nasal irritation. If a research course reaches a plateau or irritation, a washout is preferred over indefinitely raising the dose. No tolerance or withdrawal syndrome is documented in the published literature.

Use	Intranasal dose	On-cycle	Off-cycle
Acute cognitive demand	200-400 mcg once daily	5-7 days	2-5 days
Standard cognitive	300-600 mcg 1-2 times daily	2-4 weeks	1-4 weeks
Extended neurorehabilitation	clinician-dosed 0.1% solution	6-8 weeks	4 weeks or more

Stacking evidence is indirect because no trial has tested Semax in a fixed multi-peptide combination. The pairings below are based on overlapping mechanisms and community use.

Combination	Rationale	Evidence status
Semax + Selank	Shared inhibition of enkephalin-degrading enzymes and overlapping immune normalization 50	Preclinical, low risk; commonly paired in community nootropic protocols
Semax + BPC-157	Semax shifts ischemic brain gene expression away from inflammation and toward vascular and neural signaling programs 31; the same mechanism for BPC-157 is hypothetical and based only on community co-use, not published ischemic-brain gene-expression data	Theoretical; no direct combination study
Semax + Cerebrolysin or BDNF-elevating peptides	Semax raises BDNF within hours 5, so neurotrophic mechanisms may be additive	Mechanistic; no adverse data but also no direct trial
Semax + GLP-1 agonists or growth-hormone secretagogues	No shared metabolic pathway identified in the literature	No known interaction; often appears in community nootropic stacks
Semax + Melanotan II	Both are ACTH(4-10) analogues with overlapping stress-model effects 10	Caution; stacking melanocortin-active peptides is unstudied

For stimulant or serotonergic compounds, the standalone interaction signals in rodents ³⁶ should be considered before any combined research use.

Semax is registered and widely prescribed in Russia as an intranasal drug for ischemic stroke, in 0.1% and 1% formulations ¹. Indonesia has issued a special-access BPOM license for hospital-based stroke use ²⁷. It has no FDA approval, no EMA marketing authorization, and no MHRA authorization; outside Russia it is treated as an unlicensed research peptide.

It is not scheduled under the US Controlled Substances Act, and no WADA scheduling is documented in the published literature. Regulatory reviews list it as a non-approved agent with limited clinical data and absent long-term safety validation ²⁸.

Jurisdiction	Status
Russia	Registered prescription drug; 0.1% and 1% intranasal solutions
Indonesia	Special-access BPOM license, restricted to neurology/neurosurgery guidelines
United States	Not FDA approved; not scheduled; research chemical channels
EU	No EMA marketing authorization
UK	Unlicensed medicine
Australia	Not on ARTG; import requires prescription

Because it contains no steroidogenic ACTH pharmacophore, it has not attracted anabolic or steroid scheduling scrutiny. Athletes should note that absence of documented WADA classification is not proof of permitted status.

Human Semax cohorts have a favorable tolerability record. No adverse reactions were observed in a 36-patient glaucoma study using 0.1% Semax for one month ²¹, and a 60-patient optic neuropathy cohort reported no adverse events ²². A post-vitrectomy protocol with 1% Semax was associated with lower complication risk than comparator drops over 12 months ²³. Russian stroke studies report neurological recovery without a safety signal ¹.

Commonly reported research-use effects include transient nasal stinging after intranasal drops, brief headache, and mild daytime fatigue during the first days. Community reports describe these as vehicle-dependent and short lived.

Less common and theoretical findings:

• Pain modulation: increased thermal-pain sensitivity in one animal model, but analgesia against electrocutaneous shock ³⁰.
• Bleeding tendency: anticoagulant and antiplatelet activity appears under stress in rats ⁵². Human intranasal trials have not reported bleeding events.
• Opioid interaction: enkephalinase inhibition and reduced opioid analgesia in animals ⁵⁰.
• Copper redistribution: chelation of copper(II) ¹³; chronic effects are unstudied.
• Developmental risk: neonatal animal exposure changed adult catecholaminergic neuron counts and later behavior ⁵⁵, so pregnancy and pediatric use have no human safety basis.

Contraindications and unknowns: known hypersensitivity, hemorrhagic conditions, and active bleeding risk are the clearest warnings from the animal data ⁵². No human data exist beyond 12 months of follow-up ²³, and injectable human safety is undocumented ¹. Combine with anticoagulants, opioids, or seizure-prone states only with caution in research contexts.