Semax P-21
Nootropic PeptidePreclinicalAlso known as: Semax-P21, SemaxP21, Semax + P21 Hybrid
Semax P-21 is a hybrid synthetic peptide combining structural motifs from Semax and P-21 into a single molecule. Marketed as a one-shot drop-in for users running both compounds, the rationale is convenience (one peptide instead of two) and additive cognitive + anxiolytic effects. The peer-reviewed literature on this specific hybrid is essentially absent — most pharmacological characterization is by analogy to the constituent peptides.
Overview
At A Glance
Important framing: "Semax P-21" is not a single characterized compound. It is a speculative user stack combining two separate, unrelated peptides - Semax and P-21 (P021). No pharmacological study of the combination exists, so the profile below is inferred from each constituent …
Mechanism of Action
Important framing: "Semax P-21" is not a single characterized compound. It is a speculative user stack combining two separate, unrelated peptides - Semax and P-21 (P021). No pharmacological study of the combination exists, so the profile below is inferred from each constituent individually.
Semax (primary effects): A synthetic ACTH(4-7) analog that increases BDNF and NGF expression, modulates dopaminergic and serotonergic signaling, and supports attention and neuroprotection. Semax has documented clinical use in Russia.
P-21 / P021 (primary effects - animal data only): P021 is a ciliary neurotrophic factor (CNTF)-derived small-molecule peptide mimetic (Ac-DGGL(A)G-NH2). It enhances hippocampal (dentate gyrus) neurogenesis and increases BDNF expression by inhibiting the leukemia inhibitory factor (LIF) signaling pathway, and it reduces tau hyperphosphorylation through a BDNF-mediated decrease in GSK-3-beta (a major tau kinase) activity. These effects have been demonstrated only in cell and rodent models (PMID: 27400746).
Correction: Earlier claims that P-21 acts via GABA-A modulation or NGF upregulation were inaccurate - that anxiolytic/GABAergic profile belongs to the Selank/Semax family, not to P021. BDNF upregulation and neurogenesis are the intended primary effects of these peptides, not "side effects."
Overview
Semax P-21 is a hybrid synthetic peptide combining structural motifs from Semax and P-21 into a single molecule. Marketed as a one-shot drop-in for users running both compounds, the rationale is convenience (one peptide instead of two) and additive cognitive + anxiolytic effects.
The peer-reviewed literature on this specific hybrid is essentially absent — most pharmacological characterization is by analogy to the constituent peptides. Treat it as Semax-equivalent on cognition and P-21-equivalent on anxiolysis until stronger primary data emerges.
Chemical Information
IUPAC Name
Not yet available
CAS Number
Not yet available
Molecular Formula
C40H58N14O11
Molecular Mass
Not a single molecule - "Semax P-21" is two separate peptides, so no combined molecular weight applies. Per constituent: Semax (heptapeptide, Met-Glu-His-Phe-Pro-Gly-Pro) is approximately 813.9 g/mol; P-21 / P021 (Ac-DGGL(A)G-NH2, a CNTF-derived peptide mimetic) is a low-molecular-weight, blood-brain-barrier-permeable small molecule.
Amino Acid Sequence
Dosing & Protocols
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Interactions
Interaction and contraindication data is being compiled for Semax P-21. Check back soon.
General Safety Note
Always consult a qualified healthcare professional before combining research compounds. Interactions may exist that are not yet documented.
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Related Compounds
View AllAdalank
Nootropic PeptidePreclinical / Research compoundAdalank is a hybrid research peptide combining structural elements of Adamax (the adamantyl-modified Semax analog) and Selank (the anxiolytic Pro-Gly-Pro tuftsin analog).
Adamax
Nootropic PeptidePreclinical / Research compoundAdamax is a synthetic nonapeptide (Ac-MEHFPGPAG-NH2) classified as a designer analog of Semax.
Cerebrolysin
Nootropic PeptideClinicalCerebrolysin is a porcine brain-derived peptide complex developed by EVER Neuro Pharma (Austria) — a low-molecular-weight neurotrophic preparation containing a mixture of free amino acids and bioactive peptides extracted from purified pig brain proteins.
Cortexin
Nootropic PeptideMarketed in Russia/CIS (Geropharm); human clinical use with limited-quality evidence (small, mostly Russian-language studies; no Western RCT; not FDA/EMA approved)Cortexin is a purified peptide preparation extracted from cattle and pig cerebral cortex tissue — a low-molecular-weight neuropeptide complex used clinically in Russia and Eastern Europe for cognitive impairment, post-stroke recovery, encephalopathy, attention disorders, and pediatric developmental conditions. Like Cerebrolysin, Cortexin is positioned as a broad-spectrum neurotrophic preparation supplying bioactive peptides that mimic endogenous neurotrophic factors.
NA-Semax
Nootropic PeptidePreclinicalNA-Semax is the N-acetyl-l-aspartyl variant of Semax — the original ACTH(4-7) Pro-Gly-Pro analog developed at the Russian Academy of Sciences in the 1990s.
NA-Semax Amidate
Nootropic PeptidePreclinicalNA-Semax Amidate is the C-terminally amidated NA-Semax — the carboxylic acid at the peptide's C-terminus is replaced with an amide group (-NH2), which is reported to further extend metabolic half-life by resisting carboxypeptidase cleavage in addition to the aminopeptidase resistance the N-acetyl group already provides. The practical effect is a peptide with dosing-frequency use: where standard Semax often requires 3-4 daily doses to maintain effect, NA-Semax Amidate is reported (in vendor monographs and community usage) to maintain subjective effects on a 1-2x daily schedule.
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Protocols, calculator & safety for Semax P-21
Research Score
1 PubMed studies
Quality Indicators
Data Completeness
75%Research Credibility
Limited research available
Quick Facts
Half-Life
No combined-product pharmacokinetics exist. Semax (intranasal): the intact peptide is rapidly metabolized (on the order of minutes), though downstream BDNF/neurotrophic effects outlast the peptide itself. P-21 / P021: a small molecule with pharmacokinetics suitable for oral dosing in animal studies; no human PK data.
Molecular Weight
Not a single molecule - "Semax P-21" is two separate peptides, so no combined molecular weight applies. Per constituent: Semax (heptapeptide, Met-Glu-His-Phe-Pro-Gly-Pro) is approximately 813.9 g/mol; P-21 / P021 (Ac-DGGL(A)G-NH2, a CNTF-derived peptide mimetic) is a low-molecular-weight, blood-brain-barrier-permeable small molecule.
Trial Phase
Preclinical
Safety Profile
Low RiskCommon Side Effects
- • Mild nasal irritation
- • Brief alertness spike
Stop Use If
- Pregnancy/lactation
- Active mania
- Peptide allergy
Research Disclaimer
This information is for educational and research purposes only. Not intended as medical advice. Consult a healthcare professional before use.
Frequently Asked Questions
What is Semax P-21 used for in research?
Semax P-21 is a hybrid synthetic peptide combining structural motifs from Semax and P-21 into a single molecule. Marketed as a one-shot drop-in for users running both compounds, the rationale is convenience (one peptide instead of two) and additive cognitive + anxiolytic effects.
The peer-reviewed literature on this specific hybrid is essentially absent — most pharmacological characterization is by analogy to the constituent peptides. Treat it as Semax-equivalent on cognition and P-21-equivalent on anxiolysis until stronger primary data emerges.
What forms does Semax P-21 come in?
Semax P-21 is available in vials, capsules, and sprays forms.
How much does Semax P-21 cost?
Pricing varies by vendor and form.
How do I compare Semax P-21 vendors?
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Research Tools
Related Compounds
View AllAdalank
Nootropic PeptidePreclinical / Research compoundAdalank is a hybrid research peptide combining structural elements of Adamax (the adamantyl-modified Semax analog) and Selank (the anxiolytic Pro-Gly-Pro tuftsin analog).
Adamax
Nootropic PeptidePreclinical / Research compoundAdamax is a synthetic nonapeptide (Ac-MEHFPGPAG-NH2) classified as a designer analog of Semax.
Cerebrolysin
Nootropic PeptideClinicalCerebrolysin is a porcine brain-derived peptide complex developed by EVER Neuro Pharma (Austria) — a low-molecular-weight neurotrophic preparation containing a mixture of free amino acids and bioactive peptides extracted from purified pig brain proteins.
Cortexin
Nootropic PeptideMarketed in Russia/CIS (Geropharm); human clinical use with limited-quality evidence (small, mostly Russian-language studies; no Western RCT; not FDA/EMA approved)Cortexin is a purified peptide preparation extracted from cattle and pig cerebral cortex tissue — a low-molecular-weight neuropeptide complex used clinically in Russia and Eastern Europe for cognitive impairment, post-stroke recovery, encephalopathy, attention disorders, and pediatric developmental conditions. Like Cerebrolysin, Cortexin is positioned as a broad-spectrum neurotrophic preparation supplying bioactive peptides that mimic endogenous neurotrophic factors.
NA-Semax
Nootropic PeptidePreclinicalNA-Semax is the N-acetyl-l-aspartyl variant of Semax — the original ACTH(4-7) Pro-Gly-Pro analog developed at the Russian Academy of Sciences in the 1990s.
NA-Semax Amidate
Nootropic PeptidePreclinicalNA-Semax Amidate is the C-terminally amidated NA-Semax — the carboxylic acid at the peptide's C-terminus is replaced with an amide group (-NH2), which is reported to further extend metabolic half-life by resisting carboxypeptidase cleavage in addition to the aminopeptidase resistance the N-acetyl group already provides. The practical effect is a peptide with dosing-frequency use: where standard Semax often requires 3-4 daily doses to maintain effect, NA-Semax Amidate is reported (in vendor monographs and community usage) to maintain subjective effects on a 1-2x daily schedule.
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