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    Semax P-21

    Nootropic PeptidePreclinical

    Also 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.

    Half-Life: ~30-60 minutes (intranasal, hybrid-PK)MW: ~910 g/mol (approximate)1 PubMed Studies
    Last reviewed:

    Overview

    At A Glance

    Mechanism

    Mechanism (inferred from constituents):…

    Half-Life
    ~30-60 minutes (intranasal, hybrid-PK)
    Safety Notes
    Common
    Mild nasal irritationBrief alertness spike

    Mechanism of Action

    Mechanism (inferred from constituents):

    • Semax-side effects: BDNF upregulation, dopaminergic modulation, attentional drive
    • P-21-side effects: GABA-A modulation (anxiolysis without sedation), NGF upregulation
    • Combined profile: "alert + calm" — the standard goal of running Semax + Selank-family stacks

    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

    ~910 g/mol (approximate)

    Dosing & Protocols

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    Research

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    • Browse PubMed study summaries
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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

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    Adalank

    Nootropic PeptidePreclinical

    Adalank is a hybrid research peptide combining structural elements of Adamax (the adamantane-modified Semax analog) and Selank (the anxiolytic Pro-Gly-Pro tuftsin analog).

    t½ ~45-60 minutes (estimated from adamantane-modified analogs)
    PreclinicalView Profile

    Adamax

    Nootropic PeptidePreclinical / Research compound

    Adamax is a synthetic nonapeptide (Ac-MEHFPGPAG-NH2) classified as a designer analog of Semax.

    t½ ~72 hours receptor binding (community-reported); serum half-life unknown 500-2000 mcg subcutaneous (community research dosing)
    PreclinicalView Profile

    NA-Semax

    Nootropic PeptidePreclinical

    NA-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.

    t½ ~20-30 minutes (intranasal, estimated from analog data)
    3 studiesView Profile

    NA-Semax Amidate

    Nootropic PeptidePreclinical

    NA-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 leverage: 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.

    t½ ~30-45 minutes (estimated, longer than standard Semax)
    2 studiesView Profile

    P-21

    Nootropic PeptidePreclinical

    P-21 is a synthetic cyclic dipeptide — Cyclo(L-prolyl-glycine) — derived from the Selank/Semax C-terminal Pro-Gly-Pro motif.

    t½ ~1-2 hours (cyclic peptides have substantially longer half-life than linear)
    4 studiesView Profile

    P-21 Amidate

    Nootropic PeptidePreclinical

    P-21 Amidate is the amide-modified variant of P-21, the cyclic dipeptide derived from Selank.

    t½ ~2-3 hours (estimated, longer than P-21)
    1 studiesView Profile

    View Full Dosage Guide →

    Protocols, calculator & safety for Semax P-21

    Research Score

    60

    1 PubMed studies

    Quality Indicators

    Data Completeness

    75%
    Description
    Mechanism of Action
    Chemical Data
    Dosing Protocols
    Safety Profile
    PubMed Studies
    Interactions
    Vendor Listings

    Research Credibility

    1PubMed studies

    Limited research available

    Quick Facts

    Half-Life

    ~30-60 minutes (intranasal, hybrid-PK)

    Molecular Weight

    ~910 g/mol (approximate)

    Trial Phase

    Preclinical

    Safety Profile

    Low Risk

    Common 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?

    Compare prices, payment methods, shipping, and COA scores across 0 vendors.

    Research Tools

    Related Compounds

    View All

    Adalank

    Nootropic PeptidePreclinical

    Adalank is a hybrid research peptide combining structural elements of Adamax (the adamantane-modified Semax analog) and Selank (the anxiolytic Pro-Gly-Pro tuftsin analog).

    t½ ~45-60 minutes (estimated from adamantane-modified analogs)
    PreclinicalView Profile

    Adamax

    Nootropic PeptidePreclinical / Research compound

    Adamax is a synthetic nonapeptide (Ac-MEHFPGPAG-NH2) classified as a designer analog of Semax.

    t½ ~72 hours receptor binding (community-reported); serum half-life unknown 500-2000 mcg subcutaneous (community research dosing)
    PreclinicalView Profile

    NA-Semax

    Nootropic PeptidePreclinical

    NA-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.

    t½ ~20-30 minutes (intranasal, estimated from analog data)
    3 studiesView Profile

    NA-Semax Amidate

    Nootropic PeptidePreclinical

    NA-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 leverage: 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.

    t½ ~30-45 minutes (estimated, longer than standard Semax)
    2 studiesView Profile

    P-21

    Nootropic PeptidePreclinical

    P-21 is a synthetic cyclic dipeptide — Cyclo(L-prolyl-glycine) — derived from the Selank/Semax C-terminal Pro-Gly-Pro motif.

    t½ ~1-2 hours (cyclic peptides have substantially longer half-life than linear)
    4 studiesView Profile

    P-21 Amidate

    Nootropic PeptidePreclinical

    P-21 Amidate is the amide-modified variant of P-21, the cyclic dipeptide derived from Selank.

    t½ ~2-3 hours (estimated, longer than P-21)
    1 studiesView Profile

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