Side-by-Side Comparison · 2026

P21 vs Semax Amidate

P21 vs Semax Amidate — 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...

Calculate P21 dose →
Semax Amidate
Cognitive & Neurological

Semax Amidate (Semax-NH2) is Semax with C-terminal amidation - the addition of an amide group (-NH2) replacing the C-terminal carboxyl group (-COOH). This modification protects against carboxypeptidase degradation in nasal tissue, extending half-life and improving CNS bioavailabi...

Calculate Semax Amidate dose →
Key Parameters
Parameter P21 Semax Amidate
Category Cognitive & Neurological Cognitive & Neurological
Research Preclinical Research Use
Half-Life - ~6 hours (estimated)
Typical Dose 100 µg/day 100–400 µg
Frequency Daily Once or twice daily
Route Subcutaneous / Intranasal Intranasal
FDA Status Not Approved Not Approved

Calculate doses for both

Use ASCEND's free reconstitution calculator to get exact syringe draw amounts for your vial.

Calculate P21 Calculate Semax Amidate
Frequently Asked Questions
What is the difference between P21 and Semax Amidate?
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... Semax Amidate: Semax Amidate (Semax-NH2) is Semax with C-terminal amidation - the addition of an amide group (-NH2) replacing the C-terminal carboxyl group (-COOH). This modification protects against carboxypeptidas...
Which has a longer half-life, P21 or Semax Amidate?
P21 half-life: unknown. Semax Amidate half-life: ~6 hours (estimated).
Can you stack P21 and Semax Amidate?
P21 and Semax Amidate 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.