Peptides

P21 (Cerebrolysin Analog)

Evidence: animal_plus_anecdotal

Mechanism of Action

P21 is a tetrapeptide (DGGL — Asp-Gly-Gly-Leu) derived from the most active region of ciliary neurotrophic factor (CNTF, residues 148-151), identified through reverse engineering of Cerebrolysin. An adamantylated glycine enhances BBB permeability and metabolic stability. P21 works through LIF/STAT3 pathway inhibition, BDNF/TrkB/CREB signaling enhancement, and restoration of synaptic proteins (synaptophysin, synapsin I) and glutamate receptors. It promotes neurogenesis and maturation of newborn neurons in the dentate gyrus.

Dosing Protocol

Standard: Research indicates 750 mcg-1 mg daily via intranasal administration or subcutaneous injection.

Maintenance: Research indicates 500-750 mcg daily.

Administration: intranasalsubcutaneous

Timing: Morning dosing preferred for cognitive effects.

Duration: 4-8 week cycles with 4-week rest periods.

Notes

P21 was developed to capture Cerebrolysin's neurogenic benefits in a small, BBB-permeable peptide — avoiding the need for IV infusion and the complexity of Cerebrolysin's 200+ peptide mixture. It promotes neurogenesis without the adverse effects of full-length CNTF (weight loss, fatigue). Efficacy demonstrated in normal cognitive enhancement, Alzheimer's models, TBI, and age-related decline. Community reports note improved memory consolidation and reduced brain fog.

Stacking

  • Semax
  • Selank
  • Dihexa

Interactions

  • Antidepressants (SSRIs) [LOW] — P21 modulates BDNF/CREB pathway which is also targeted by antidepressants; potentially synergistic.
  • CNTF-related therapies [MEDIUM] — Shared pathway; monitor for overstimulation.

Contraindications

  • Pregnancy and breastfeeding
  • Active seizure disorders

Side Effects

  • Mild headache
  • Nasal irritation (intranasal)
  • Increased appetite (CNTF pathway modulation)
  • Vivid dreams

Key Papers

  • 10.1016/j.neuroscience.2012.02.046
  • 10.1016/j.nbd.2013.01.004

Source Quality

Research-grade supplier only. Verify adamantylated glycine modification on COA.

Disclaimer: This information is for educational purposes only and is not medical advice. BioAccelera Labs does not diagnose, treat, or prescribe. Consult a licensed healthcare provider before using any compound.

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