N-Acetyl Semax

Typical use cases

Dosing guidelines

Titration

No formally studied titration schedule exists; community sources typically describe staying within a fixed multi-week cycle at the lower end of the reported range rather than continuously escalating. Educational information only, not a dosing recommendation.

Reconstitution

Supplied as a lyophilized powder. For intranasal use it is commonly reconstituted with bacteriostatic or sterile saline (or sterile water) and transferred to a nasal spray/dropper bottle; a ~0.1% solution corresponds to roughly 1 mg peptide per 1 mL diluent. Swirl gently rather than shake until fully dissolved.

Injection sites

Primarily intranasal (one or both nostrils); no injection required. Some researchers also use subcutaneous administration, but the intranasal route is the conventional and most-studied delivery for Semax-class peptides.

Storage & handling

Store lyophilized powder refrigerated (2-8°C) or frozen for long-term storage, protected from light. After reconstitution, keep refrigerated at 2-8°C and use within a few weeks.

Side effects

• Nasal/sinus irritation or stinging (intranasal use) Mild · Common
• Headache Mild · Uncommon
• Overstimulation, restlessness, or jitteriness Mild · Uncommon
• Sleep disturbance / insomnia (especially with late-day dosing) Mild · Uncommon
• Irritability or transient mood changes Moderate · Rare
• Allergic/hypersensitivity reaction Severe · Rare

Research summary

N-Acetyl Semax is a chemically modified version of Semax (Met-Glu-His-Phe-Pro-Gly-Pro), itself a synthetic analogue of the ACTH(4-10) fragment developed at the Institute of Molecular Genetics of the Russian Academy of Sciences (Ashmarin/Myasoedov group) and used in Russia for stroke and cognitive indications. The N-terminal acetyl group is intended to slow aminopeptidase degradation and prolong action relative to native Semax, whose plasma half-life is only minutes; however, the acetylated derivative itself has essentially no dedicated published human pharmacokinetic or efficacy trials, so almost all evidence is inferred from the parent peptide. The mechanistic literature, largely preclinical, indicates Semax upregulates brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) and their Trk receptors (e.g., Bdnf, TrkA, TrkC) in hippocampal and ischemic brain tissue, plausibly through CREB-linked pathways, and modulates dopaminergic, serotonergic, and immune/vascular gene programs (BMC Genomics 2014; Cell Mol Neurobiol 2010; Neurochemical Research 2005). Human data on the parent compound are limited to small studies reporting improved attention and memory after intranasal application, alongside Russian clinical use in acute ischemic stroke. Key limitations are pronounced: most clinical literature is Russian-language and not replicated in large Western randomized controlled trials, sample sizes are small, and the acetylated and amidated variants sold to researchers are frequently conflated despite differing molecular weights and pharmacology. Long-term safety, optimal dosing, and true human pharmacokinetics of N-Acetyl Semax specifically remain uncharacterized. As such, claims about enhanced potency or duration over Semax are largely theoretical extrapolations from chemistry rather than direct clinical demonstration.

Key references

• https://pmc.ncbi.nlm.nih.gov/articles/PMC3987924/
• https://pmc.ncbi.nlm.nih.gov/articles/PMC11498467/
• https://doi.org/10.1007/s11064-005-8826-8
• https://doi.org/10.1016/j.mehy.2006.07.017
• https://pubchem.ncbi.nlm.nih.gov/compound/9811102

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