Side-by-Side Comparison · 2026

P21 vs PE-22-28

P21 vs PE-22-28 — mechanism, half-life, dosing, and research status compared. Which is right for your protocol?

P21
Cognitive & Neurological

P21 is a synthetic peptide derived from ciliary neurotrophic factor (CNTF), designed to promote neurogenesis - the formation of new neurons - in the hippocampus and olfactory bulb. CNTF is a potent neurotrophic factor but has poor CNS penetration and causes significant systemic s...

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PE-22-28
Cognitive & Neurological

PE-22-28 is a synthetic fragment of spadin (a naturally occurring peptide derived from the NTSR3/sortilin propeptide) that antagonizes TREK-1, a two-pore domain potassium channel (K2P channel) that regulates neuronal excitability. TREK-1 is strongly implicated in depression and c...

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Key Parameters
Parameter P21 PE-22-28
Category Cognitive & Neurological Cognitive & Neurological
Research Preclinical Preclinical
Half-Life - -
Typical Dose 100 µg/day 100–200 µg
Frequency Daily Daily
Route Subcutaneous / Intranasal Subcutaneous / Intranasal
FDA Status Not Approved Not Approved

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Frequently Asked Questions
What is the difference between P21 and PE-22-28?
P21: P21 is a synthetic peptide derived from ciliary neurotrophic factor (CNTF), designed to promote neurogenesis - the formation of new neurons - in the hippocampus and olfactory bulb. CNTF is a potent ne... PE-22-28: PE-22-28 is a synthetic fragment of spadin (a naturally occurring peptide derived from the NTSR3/sortilin propeptide) that antagonizes TREK-1, a two-pore domain potassium channel (K2P channel) that re...
Which has a longer half-life, P21 or PE-22-28?
P21 half-life: unknown. PE-22-28 half-life: unknown.
Can you stack P21 and PE-22-28?
P21 and PE-22-28 are in the same category and used together in research protocols. Always consult relevant literature and follow appropriate guidelines.

For research use only. Not medical advice. ASCEND does not conduct or endorse any specific research protocol. Always consult relevant scientific literature and regulatory guidelines.