N-Acetyl Semax Amidate [Nasal Spray]

Description

What is N-Acetyl Semax Amidate?

N-Acetyl Semax Amidate (also referred to as NA-Semax-NH₂ or NA-Semax Amidate) is a structurally modified analog of Semax in which the N-terminus of the heptapeptide has been acetylated and the C-terminus has been converted from a free carboxylic acid to an amide group. These dual terminal modifications are applied to alter the peptide’s resistance to exopeptidase-mediated degradation and to modulate its physicochemical and potentially its pharmacodynamic properties relative to the parent compound.

The core amino acid sequence (Met-Glu-His-Phe-Pro-Gly-Pro) is retained in N-Acetyl Semax Amidate. The N-acetyl and C-amide modifications are established strategies in peptide chemistry to improve metabolic stability and alter membrane permeability in preclinical pharmacological research settings.

N-Acetyl Semax Amidate has no approved therapeutic application. The Food and Drug Administration has not approved this compound for human or veterinary use. It is not a dietary supplement or consumer product. It is intended exclusively for laboratory and research purposes.

All preclinical studies referenced in this document were conducted under institutional oversight consistent with IRB, IACUC, and AWA guidelines. N-Acetyl Semax Amidate is supplied by RCDbio exclusively for use under equivalent institutional research compliance frameworks. 

Chemical Properties

Property	Detail
Product Type	Synthetic Heptapeptide / Modified Melanocortin Analog
Product Name	N-Acetyl Semax Amidate Nasal Spray
Application	Scientific / Research Use Only
CAS Number	2920938-90-3
Molar Mass	854.97 g/mol
Chemical Formula	C₃₉H₅₄N₁₀O₁₀S
IUPAC Name	N-acetyl-Met-Glu-His-Phe-Pro-Gly-Pro-NH₂ (full systematic IUPAC name corresponds to the N-acetylated, C-terminally amidated heptapeptide sequence of Semax)
Synonyms	NA-Semax Amidate; NA-Semax-NH₂; Acetyl-MEHFPGP-amide; N-Acetyl Semax Amide
Physical Form	Aqueous nasal spray solution (lyophilized peptide reconstituted in sterile buffered solution)
Solubility	Soluble in water and aqueous buffers
Storage (Lyophilized)	−20°C, desiccated, protected from light
Storage (Reconstituted / Nasal Spray)	2–8°C; use within 28 days; protect from light; do not freeze reconstituted solution
PubChem CID	172638603
Purity	≥98% (HPLC verified, independent third-party laboratory analysis; COA available per batch)
WADA Status	N-Acetyl Semax Amidate is not explicitly listed by name on the 2026 WADA Prohibited List. As a structural analog of Semax with melanocortin receptor-relevant activity, researchers operating under WADA-governed contexts should consult the applicable prohibited list under the S0 (Non-Approved Substances) or S2 class provisions and seek guidance from their governing body before use.

How Does N-Acetyl Semax Amidate Work?

N-Terminal Acetylation and C-Terminal Amidation: Structural Rationale

Mechanistically, the introduction of an N-terminal acetyl group and a C-terminal amide in place of the free carboxylate of Semax has been investigated as a strategy to reduce susceptibility to aminopeptidase- and carboxypeptidase-mediated degradation in biological matrices. These terminal modifications are routinely applied in preclinical peptide research to extend ex vivo stability profiles and have been associated in the broader peptide pharmacology literature with altered receptor binding kinetics and membrane interaction characteristics. Whether these modifications produce quantitatively distinct receptor interaction profiles at MC4/MC5 receptor subtypes relative to unmodified Semax has not been directly characterized in published peer-reviewed receptor binding studies specific to N-Acetyl Semax Amidate as of this publication date.

Melanocortin Receptor Pharmacology

As with the parent Semax compound, N-Acetyl Semax Amidate is investigated in the context of melanocortin receptor pharmacology. The core His-Phe pharmacophore sequence, which is central to melanocortin receptor engagement in the ACTH(4-10) fragment class, is preserved in the modified analog. Preclinical evidence from the Semax parent literature positions MC4 and MC5 receptor subtypes as candidate interaction sites; receptor binding studies specific to the acetylated/amidated form have not been independently replicated in peer-reviewed literature available as of June 2026. Researchers are directed to parent compound receptor pharmacology literature for mechanistic context, with the caveat that terminal modifications may alter binding parameters.

BDNF/TrkB Pathway Relevance

The BDNF/TrkB signaling axis modulated by the parent Semax compound in rodent hippocampal preparations is considered a relevant mechanistic context for N-Acetyl Semax Amidate research, given sequence conservation. The degree to which terminal modifications influence upstream receptor interactions and downstream BDNF transcriptional responses in neuronal cell preparations has not been independently characterized in published literature and remains an open area for preclinical investigation.

Monoaminergic System Interactions

In the broader Semax analog literature, compounds within this structural class have been associated with modulation of dopaminergic and serotonergic systems in rodent brain preparations. N-Acetyl Semax Amidate is investigated in preclinical contexts examining potential interactions with monoaminergic signaling pathways, though compound-specific data for the acetylated/amidated form is limited and findings should be contextualized against the parent compound literature.

Key Research Findings

These findings are drawn from preclinical research on Semax and closely related structural analogs. Compound-specific peer-reviewed data for N-Acetyl Semax Amidate is limited. Data remains limited and findings are not consistent across all models. This section does not constitute clinical evidence.

• Structural stability enhancement: N-terminal acetylation and C-terminal amidation modifications in synthetic peptides have been broadly demonstrated in the peptide chemistry literature to confer resistance to exopeptidase-mediated degradation in plasma and tissue preparations.
• Melanocortin pharmacophore conservation: The His-Phe core sequence critical for MC4/MC5 receptor interaction is retained in the N-Acetyl Semax Amidate structure; receptor engagement characteristics are investigated in the context of parent analog pharmacology.
• BDNF axis research context: The Semax parent compound has been observed in rodent hippocampal preparations to produce up to a 1.4-fold increase in BDNF protein and 1.6-fold increase in TrkB phosphorylation; these findings provide the mechanistic research context for analog investigation. [Dolotov et al., 2006; PMID: 16996037]
• Monoamine system modulation: Semax-class analogs have been investigated in rodent preparations for interactions with dopaminergic and serotonergic tone; compound-specific data for N-Acetyl Semax Amidate is absent from the peer-reviewed literature as of the date of this publication.
• Neuropeptide delivery optimization: Dual terminal modification strategies are actively investigated in neuropeptide delivery research as a route to improving CNS bioavailability via intranasal administration models.

What Are the Potential Research Applications of N-Acetyl Semax Amidate?

N-Acetyl Semax Amidate Nasal Spray is investigated in preclinical research contexts including the following:

• Peptide stability and pharmacokinetic research: Comparative in vitro plasma stability studies examining the impact of N-acetylation and C-terminal amidation on enzymatic degradation rates relative to unmodified Semax and other melanocortin analogs.
• Melanocortin receptor binding characterization: Receptor competition assays at MC4 and MC5 subtypes examining how terminal modifications influence binding affinity, selectivity, and functional receptor response in cell-based preparations.
• Intranasal neuropeptide bioavailability research: Rodent in vivo and ex vivo models examining peptide-CNS transport, olfactory mucosal absorption, and regional brain distribution following intranasal delivery of terminally modified peptide analogs.
• Neurotrophin pathway investigation: In vitro hippocampal cell preparations and in vivo rodent systems examining BDNF/TrkB pathway engagement by structurally modified Semax analogs.
• Structure-activity relationship (SAR) research: Comparative preclinical pharmacology studies examining how N-terminal acetylation and C-terminal amidation modulate receptor interaction profiles, CNS penetration, and in vitro biological activity relative to the parent compound and other Semax variants.

What Are the Potential Side Effects of N-Acetyl Semax Amidate?

The following observations are based on the preclinical safety profile of the parent Semax compound and general peptide class considerations. Compound-specific toxicity data for N-Acetyl Semax Amidate is not available in peer-reviewed literature as of this publication date.

• No compound-specific acute toxicity data is available in peer-reviewed literature for N-Acetyl Semax Amidate. Researchers should not extrapolate safety from the parent Semax compound without independent verification.
• CNS-active peptide class risks: As a compound investigated for melanocortin receptor interaction and potential neuromodulatory activity, N-Acetyl Semax Amidate is handled with precautions consistent with a CNS-active research peptide.
• No chronic toxicity data for any species is available. Long-term safety, reproductive toxicity, genotoxicity, and organ-level toxicity are uncharacterized.
• Data remains limited. No human safety data has been established.

Risk & Handling

Handling Precautions

N-Acetyl Semax Amidate Nasal Spray is intended for use by trained laboratory personnel only. The following precautions apply:

• PPE required: nitrile gloves, laboratory coat, and eye protection at minimum.
• Handle reconstituted nasal spray solution in a clean laboratory environment; avoid aerosol generation during any manipulation or transfer operations.
• Pipetting and aliquoting should be performed with calibrated laboratory equipment; avoid contact with mucous membranes, eyes, or skin.
• Dispose of biological waste and spent solutions in accordance with institutional biosafety protocols and applicable local regulations.

Exposure Risks

Risk Tier: MODERATE

N-Acetyl Semax Amidate is a biologically active synthetic peptide with structural features associated with melanocortin receptor activity and neuromodulatory properties. No human safety data has been established. Compound-specific acute and chronic toxicity data are absent from the peer-reviewed literature. Researchers should apply standard CNS-active peptide handling precautions consistent with a MODERATE biological hazard tier until compound-specific safety data is established.

Storage

• Lyophilized: Store at −20°C in a desiccated, airtight container protected from light and moisture. Stable for up to 24 months under these conditions.
• Reconstituted / Nasal Spray: Maintain at 2–8°C. Use within 28 days of preparation. Do not freeze the reconstituted solution. Protect from direct light exposure.
• Freeze-thaw: Avoid repeated freeze-thaw cycles of the lyophilized peptide. Aliquot prior to first use to preserve peptide integrity.
• Supplied in sterile, sealed amber glass or HDPE spray container as appropriate to preserve photostability.

FAQs

Q1: How does N-Acetyl Semax Amidate differ from Semax in terms of research applications? The primary distinction is structural: N-Acetyl Semax Amidate incorporates an N-terminal acetyl group and a C-terminal amide, modifications that are investigated for their effects on enzymatic stability and receptor interaction profiles in preclinical systems. Research applications involving comparative pharmacology, peptide stability modeling, and structure-activity relationship (SAR) analysis represent areas where the modified analog may provide distinct investigational value relative to unmodified Semax. Researchers should note that published compound-specific data for N-Acetyl Semax Amidate remains limited as of June 2026.

Q2: What is the expected stability of N-Acetyl Semax Amidate in solution? Terminal modifications (N-acetylation and C-amidation) are broadly associated in the peptide chemistry literature with reduced susceptibility to exopeptidase-mediated degradation. Reconstituted nasal spray solution should be maintained at 2–8°C and used within 28 days. Lyophilized peptide stock should be stored at −20°C, desiccated and protected from light, for up to 24 months from manufacture.

Q3: Has N-Acetyl Semax Amidate been evaluated in any in vivo rodent models? Compound-specific peer-reviewed in vivo data for N-Acetyl Semax Amidate is not available in the publicly accessible literature as of the date of this publication. Research context is primarily derived from the parent Semax compound and the broader Semax analog literature. Investigators planning in vivo studies are directed to design appropriate dose-range finding and pharmacokinetic characterization experiments using established preclinical protocols.

Q4: What is the WADA classification status for N-Acetyl Semax Amidate? N-Acetyl Semax Amidate is not explicitly named on the 2026 WADA Prohibited List. However, the WADA S0 (Non-Approved Substances) class broadly covers pharmacologically active substances lacking regulatory approval for therapeutic use in humans. Researchers operating under WADA-governed sports contexts should consult current prohibited list guidance and their applicable governing body independently.

Q5: What storage conditions are required for the lyophilized form? Lyophilized N-Acetyl Semax Amidate should be stored at −20°C in a sealed, desiccated container protected from light and moisture. Aliquot prior to initial use to minimize exposure of the bulk stock to freeze-thaw cycling. Under these conditions, stability of up to 24 months from the manufacturing date is expected.

Related Research Compounds

Section pending internal URL confirmation. All products listed are for laboratory and research purposes only.

References

Research transparency note: As of June 2026, no peer-reviewed publications specific to N-Acetyl Semax Amidate as an independent compound are available in the PubMed-indexed literature. The following references relate to the parent compound Semax, the melanocortin receptor pharmacology class, and neuropeptide terminal modification research relevant to the investigational context of N-Acetyl Semax Amidate.

1. Dolotov OV, Karpenko EA, Inozemtseva LS, et al. Semax, an analog of ACTH(4-10) with cognitive effects, regulates BDNF and trkB expression in the rat hippocampus. Brain Research. 2006;1117(1):54–60. https://pubmed.ncbi.nlm.nih.gov/16996037/
2. Filippenkov IB, Stavchansky VV, Denisova AE, et al. Brain Protein Expression Profile Confirms the Protective Effect of the ACTH(4-7)PGP Peptide (Semax) in a Rat Model of Cerebral Ischemia-Reperfusion. International Journal of Molecular Sciences. 2021;22(12):6179. https://pubmed.ncbi.nlm.nih.gov/34201112/
3. Medvedeva EV, Dmitrieva VG, Povarova OV, et al. The peptide semax affects the expression of genes related to the immune and vascular systems in rat brain focal ischemia: genome-wide transcriptional analysis. BMC Genomics. 2014;15:228. https://pubmed.ncbi.nlm.nih.gov/24661604/
4. Stavchansky VV, Denisova AE, Filippenkov IB, et al. The Peptide Drug ACTH(4-7)PGP (Semax) Suppresses mRNA Transcripts Encoding Proinflammatory Mediators Induced by Reversible Ischemia of the Rat Brain. Genes (Basel). 2021;12(6):867. https://pubmed.ncbi.nlm.nih.gov/34097675/

Disclaimer

N-Acetyl Semax Amidate Nasal Spray is exclusively for laboratory research purposes. RCDbio products are not intended to diagnose, prevent, treat, or cure any disease or medical condition.

The Food and Drug Administration has not evaluated the statements on our website. This product is not approved for human or veterinary use. Researchers must comply with all applicable local, state, and federal laws and regulations governing the purchase and use of research compounds. By purchasing, you agree to our Terms and Conditions. RCDbio reserves the right to refuse sales to unauthorized individuals.

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