Skip to content

    Research Use Only

    This site is an educational resource for research compounds. We do not endorse human consumption of any compound. BodyHackGuide and BHG Labs share common ownership; we rank every vendor on the same public methodology, and we earn a commission on purchases through our links. By entering, you confirm you are 21 years of age or older and agree to our Terms & Privacy Policy.

    100K+ researchers trust BodyHackGuide — Join r/BodyHackGuide
    Nootropic PeptidePreclinical

    Semax P-21 Dosage Guide: Protocols, Calculator & Safety

    Everything you need to know about Semax P-21 dosing — protocols, safety, and where to buy.

    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.

    Dosage Calculator

    Calculate exact dosing for Semax P-21.

    Dosing Protocols

    Beginner

    Beginner

    • 200-400 mcg/day intranasal, once daily, 14 days
    Standard

    Intermediate

    • 400-600 mcg/day, 1-2x daily, 21 days on / 7 off
    Advanced

    Advanced

    • 600-1,000 mcg/day, 2x daily, 30-day cycles

    Commonly Stacked With

    A drop-in replacement for Semax + P-21 co-dosing. Stacks with Cerebrolysin or Cortexin for amplified neurotrophic effects.

    Additional Notes

    The doses shown are extrapolated from intranasal Semax practice and do not represent a validated protocol. No pharmacological study has established a dose for a Semax + P021 combination. Note that P021 was administered orally in animal studies, not intranasally, so intranasal co-dosing with Semax is unstudied. Research use only.

    Frequently Asked Questions

    What is the recommended Semax P-21 dosage?

    Dosage for Semax P-21 varies by protocol. Consult a qualified healthcare provider.

    How often should I take Semax P-21?

    Administration frequency depends on the specific protocol. Consult current research literature.

    Does Semax P-21 need to be cycled?

    Cycling requirements depend on the protocol. Follow established research guidelines.

    What are Semax P-21 side effects?

    Side effects vary by individual. Consult published research for comprehensive safety information.

    Where can I buy Semax P-21?

    Visit our vendor directory to find trusted sources for Semax P-21.

    Free 2026 Peptide Cheat Sheet — 50 pages, PDF

    Reconstitution math, concentration charts, half-lives, and vendor trust tiers. The reference we wish we had on day one.

    Download Free
    Shop BHG Labs · 20% off with BHG20