N-Acetyl Semax Amidate

N-Acetyl Semax Amidate is a doubly capped analogue of Semax, a synthetic heptapeptide based on a short fragment of the hormone ACTH fused to a Pro-Gly-Pro tail ¹³. Semax is a melanocortin-family peptide with nootropic and neuroprotective activity, but it is nearly free of the corticosteroid-releasing hormonal action of full ACTH ⁹.

The amidate version adds two chemical caps aimed at the peptide's main breakdown routes. The N-terminal acetyl group blocks aminopeptidase cleavage, while the C-terminal amide blocks carboxypeptidase attack on the free carboxyl group ²³. The acetyl cap also changes how the peptide coordinates copper and zinc, which matters because metal handling is part of Semax's mechanism ²⁰.

Most human evidence comes from the parent peptide Semax, which has been used in Russia for acute ischemic stroke and several eye conditions ¹⁹. The amidate itself has no published human efficacy trials; its direct evidence base is proteolytic stability and metal-coordination chemistry ²⁰.

Semax was designed to keep ACTH-like activity in the brain without driving adrenal corticosteroid output ⁹. In animal studies, it raises brain-derived neurotrophic factor (BDNF), a protein that supports neuron survival and plasticity, and it normalizes gene-expression programs disrupted by stress or ischemia ¹⁶.

Primary receptor target: the µ-opioid receptor (MOR; gene Oprm1). In a spinal cord injury model, Semax engaged MOR, increased the deubiquitinase USP18, and modulated deubiquitination of the RNA demethylase FTO; knockdown of USP18 removed the recovery effect ³.

BDNF hub: Semax stimulates BDNF expression across rat brain regions in vivo ²⁸. In chronic unpredictable stress, 60 nmol/kg intraperitoneal restored hippocampal BDNF losses and reversed anhedonia ⁷. In ischemic brain, Semax activates CREB while suppressing damage markers MMP-9, c-Fos, and phospho-JNK ¹⁶.

Copper oxidative protection: Semax binds Cu(II) with high affinity ²¹, strips Cu(II) from copper-amyloid beta complexes, silences Cu-catalyzed reactive oxygen species production, and protects neuron-like cells ⁶. It also blocks Cu(II)-dependent amyloid fibril formation in membrane models ¹⁴.

Anti-inflammatory action: after cerebral ischemia-reperfusion, Semax suppresses induction of Il1a, Il1b, Il6, Ccl3, and Cxcl2 mRNA ¹⁷.

Glutamatergic modulation: Semax alters NMDA glycine-site binding in cortex and hippocampus ¹¹, and analogues potentiate AMPA-receptor currents in cerebellar Purkinje neurons ³⁸.

Stress-axis damping: at 100 µg/kg intraperitoneal, Semax normalizes hippocampal gene expression and behavioral stress responses in acute restraint stress ³⁶, and across a range of doses it lowers stress-elevated corticosterone and reduces stress-related colon pathology ³⁷.

The caps are the functional identity of the amidate. Acetylation blocks aminopeptidase access and confers resistance to proteolysis ²³, while amidation protects the site processed by carboxypeptidases ²⁴. Pharmacodynamic changes can outlast plasma exposure: brain transcriptome changes were still detectable 22.5 hours after a single dose in rats ³⁵.

The strongest human evidence belongs to parent Semax.

Stroke recovery. Adding Semax to intensive therapy in acute ischemic stroke accelerated regression of focal and motor deficits versus a control cohort ²⁹. Later work found efficacy varied by stroke stage ¹⁹.

Eye and nerve protection. In primary open-angle glaucoma, 0.1% Semax preserved optic nerve structure with no adverse reactions in a 36-patient trial ²². In vascular optic neuropathy, endonasal 0.1% electrophoresis produced better early efficacy than controls ¹⁵. In non-proliferative diabetic retinopathy, Semax with calcium dobesilate improved perfusion markers while controls deteriorated ⁵.

Cognition. A 1996 human study reported nootropic-like effects on EEG and neuropsychometric measures ³⁰. Five-day courses improved learning and verbal memory in neurosurgical rehabilitation patients ³¹. In rats with chronic brain ischemia, intranasal Semax restored short- and long-term memory ⁸.

Stress and mood. In chronic unpredictable stress, Semax reversed anhedonia, restored hippocampal BDNF, and reduced adrenal hypertrophy ⁷. It also normalized anxiety- and depression-like behavior in stress models ⁹ and restored stress-elevated inflammatory cytokines toward control values ¹².

Neuroprotection in models. Semax and a derivative improved cognition and reduced amyloid burden in an Alzheimer mouse model ³³. In vitro, Semax binds copper and silences copper-amyloid toxicity ⁶.

The amidate itself is supported by stability and coordination chemistry, not by separate human efficacy trials ²⁰.

Published human protocols exist for parent Semax; protocols for N-Acetyl Semax Amidate come from community research practice. The timeline card shows one common intranasal protocol.

The most studied clinical formulation is 0.1% intranasal Semax. In acute ischemic stroke, it was used as part of intensive care during the acute treatment course ¹⁹. In glaucoma, 0.1% intranasal drops were used daily for roughly one month ²². In optic neuropathy, an 8-day endonasal electrophoresis course was used ¹⁵.

Amidate community protocols. Community research protocols typically use intranasal doses of 100-300 µg once or twice daily, or subcutaneous doses of 100-250 µg once daily, for 2-4 week cycles. Titration in 50 µg increments every 3-4 days is common, starting at the low end of the range. Dosing is usually split morning and early afternoon, because Semax increases excitability of hippocampal neurons in vitro and has an activating profile ⁴.

Body-weight scaling. Preclinical parent-peptide doses convert to roughly 2-5 µg/kg subcutaneous or 3-8 µg/kg intranasal by standard allometric scaling; those ranges bracket community amidate dosing. The rat antidepressant-effective dose of 60 nmol/kg is about 50 µg/kg and scales to roughly 8 µg/kg human-equivalent.

Route comparison. Intranasal is the evidence-anchored route for parent Semax ²⁹. Subcutaneous use is reported in community protocols for predictable daily dosing, but has no published amidate-specific data. Oral use is not used in research because of rapid peptide breakdown.

Timing and cycles. Morning dosing is standard in community practice; evening dosing is avoided to limit sleep disruption. Published rat protocols used 7 days intranasal ¹⁸ and 20 days intraperitoneal ¹²; community amidate cycles are typically 2-4 weeks on, 4 weeks off.

For research-grade lyophilized N-Acetyl Semax Amidate, community protocols use bacteriostatic water as the standard diluent; sterile water is acceptable for single-use applications. Semax and its analogues are hydrophilic heptapeptides, so they dissolve readily in water without pH adjustment or organic solvents.

Slowly add the diluent down the inside of the vial wall, then swirl gently rather than vortexing. Lyophilized powder is typically stored around -20°C for long-term use, or at 2-8°C for shorter periods, and should stay dry and protected from light. Reconstituted solution is refrigerated at 2-8°C; community guidance estimates about 30 days of use in bacteriostatic water and a shorter shelf life in plain sterile water.

The chemical caps confer resistance to enzymatic breakdown in biological media ²³, but they do not replace cold storage or sterile technique. The interactive calculator on this page handles dilution volumes and dose-by-concentration math.

Interaction data for the amidate specifically are limited to the effect of acetylation on metal coordination and proteolytic stability ²⁰. Other patterns are extrapolated from parent Semax, mostly in animal studies.

• Opioids. Parent Semax attenuates opioid-induced analgesia in rats ⁵¹ and reduces withdrawal signs in morphine-dependent rats ⁵⁰. The expected interaction is reduced opioid analgesic effect.
• Bleeding risk. Semax has anticoagulant and antiplatelet effects in stressed rats ⁴². Combining with anticoagulants or antiplatelet drugs carries a theoretical additive bleeding risk.
• Stimulants. Semax activates dopaminergic and serotoninergic systems in rodents ²⁷, so amphetamine-class stimulants or methylphenidate may have additive effects on arousal, heart rate, and blood pressure.
• GABA and depressants. Semax modulates GABA- and glycine-activated currents in vitro ⁴⁹. In chronic brain ischemia, combined use with hopantenic acid improved recovery without adverse synergy in rats ⁴⁶.
• Antidepressants and stress models. In animals, Semax normalized behavior after fluvoxamine exposure ⁴⁷ and showed antidepressant-like effects with hippocampal BDNF restoration ⁷; combination with SSRIs appears complementary, while MAOIs have no direct data.
• Liver stress. In rats, Semax protected against drug-induced hepatitis from anti-tuberculosis therapy ⁴⁸.
• Supplements. Community practice separates copper and zinc supplements by 2-4 hours from dosing because Semax binds these metals ²⁰. Fish oil, ginkgo, garlic, and curcumin may add antiplatelet activity in theory.

No controlled cycling trials exist for the amidate. Community cycles are informed by parent-peptide receptor changes and the analogue's longer stability.

Common patterns:

• Standard: 2-4 weeks on, 4 weeks off.
• Conservative first cycle: 2-3 weeks on, 1-2 weeks off.
• Intermittent: 5 days on, 2 days off within a longer cycle.

The rationale is not purely preference. Subchronic Semax dosing in animals altered metabotropic glutamate II receptor density by 19% and NMDA glycine-site binding by up to 66%, with direction depending on route and brain region ¹⁰. Repeated dosing therefore measurably remodels receptor binding in animals, and scheduled washout is a mechanistic hedge.

Semax also activates dopaminergic and serotoninergic systems ²⁷. Community practice uses finite cycles to avoid sustained monoaminergic drive and fading response. Because the acetyl and amide caps slow enzymatic breakdown ²³, the amidate may be longer-acting than parent Semax, making off periods a practical hedge against accumulation.

Published safe-use signals are short-term: rat protocols used daily treatment for 7-20 days ¹², and human parent-Semax cohorts reported no adverse reactions over similarly short courses ²². No withdrawal syndrome has been reported in community use or animal stress-model cessation.

Community stacks commonly pair the amidate with other cognitive or repair peptides, with limited formal evidence.

• Selank: Both peptides have been studied for stress-related cytokine normalization ¹², and both alter NMDA glycine-site binding, with differences by peptide and mouse strain ¹¹. Community protocols stack them widely without reported conflict.
• Noopept: Overlapping NMDA glycine-site pharmacology ¹¹; community stacks typically start at the lower end of each dose range.
• BPC-157 and TB-500: No direct published interaction data; these are used for repair while Semax analogues are used for neurotropic and nootropic effects, so community protocols combine them as distinct mechanisms.
• GHRH and ghrelin mimetics such as ipamorelin and CJC-1295: No shared pathway identified in the research base; community stacks report no conflict.
• Racetams and cholinergics such as alpha-GPC or citicoline: No published conflict; these are common nootropic combinations in community practice.
• BDNF-supportive supplements such as lion's mane: Possible synergy is theoretical, based on Semax raising BDNF in animal studies ²⁸.

Because the acetylated amidate resists proteolysis ²³, community protocols often use once-daily dosing within a stack.

N-Acetyl Semax Amidate has no FDA or EMA approval and no marketing authorization in Western jurisdictions. A 2026 regulatory review listed Semax-class compounds among investigational peptides lacking long-term safety validation ¹.

The parent peptide Semax is a registered pharmaceutical in Russia, prescribed for ischemic stroke and cognitive indications ¹⁹. Indonesia grants Semax special-access authorization through BPOM for hospital-specific neurology guidelines ⁵⁴. The amidate derivative differs from the registered Semax formulation by N-terminal acetylation and C-terminal amidation, and no published source documents registration of the modified form.

In the United States, it is not listed on any CSA schedule, and no published source describes DEA scheduling actions for Semax or its acetylated analogues. It is distributed through research-chemical channels with not-for-human-use labeling.

For sports, a 2026 review found no WADA prohibited-list entry specific to Semax or its derivatives ¹. No published enforcement actions involving Semax or acetylated analogues were identified. However, athletes operating under anti-doping rules need to verify the current prohibited list before competition.

No human safety trials exist for N-Acetyl Semax Amidate itself. The available human safety record comes from parent Semax.

Parent Semax has a benign short-course clinical profile. In a 36-patient glaucoma study using 0.1% Semax, no adverse reactions were reported ²². A post-vitrectomy cohort and an 87-patient diabetic retinopathy cohort also reported no treatment-related adverse events ². Russian post-stroke use has not carried a serious complication signal ¹⁹.

Community users most often report transient nasal irritation, sneezing, mild headache, or mild restlessness early in a course. Insomnia and jitteriness are dose- and timing-dependent and appear more often above 600 µg per day or with late-day dosing. These reports are community observations, not clinical trial data.

Theoretical cautions come from animal and in-vitro work. Semax modified audiogenic seizure expression in neonatal mice ⁴³, which suggests caution in epilepsy research. It exerts anticoagulant and antiplatelet effects in stressed rats ⁴², which supports caution alongside antithrombotics. It binds copper with high affinity, and the acetyl modification changes copper and zinc coordination ²⁰.

Contraindications in community guidance include known hypersensitivity to Semax or related Pro-Gly-Pro peptides, active intracranial hemorrhage, and concurrent use of stimulants. Pregnancy and lactation have no human data and are avoided. No randomized controlled trial exists for the amidate, no formal drug-drug interaction studies are published, and long-term continuous use has no safety data.