P21 vs Semax
Side-by-side comparison of key properties, dosing, and research.
- Summary
- P21 is a synthetic peptide derived from CNTF (ciliary neurotrophic factor) that promotes hippocampal neurogenesis, enhances memory and spatial learning, and may reduce amyloid-beta pathology. It is used as a neurogenic and cognitive enhancer with potential anti-Alzheimer's applications.
- Semax is a synthetic heptapeptide derived from ACTH developed in Russia. It is a potent nootropic that enhances memory, focus, and provides neuroprotection. Approved in Russia for cognitive disorders, stroke recovery, and traumatic brain injury.
- Half-Life
- Not well characterized; likely short, but neurogenic effects persist long after administration
- Minutes (but effects persist for hours via BDNF induction)
- Admin Route
- SubQ, Intranasal
- Intranasal, SubQ
- Research
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- Typical Dose
- 100–500 mcg
- 0.25–1 mg (250–1000 mcg)
- Frequency
- Once daily
- 1–2 times daily
- Key Benefits
- Promotes hippocampal neurogenesis
- Enhances spatial memory and learning
- Increases BDNF expression
- Reduces amyloid-beta plaque formation (animal models)
- Anti-tau pathology potential
- Cognitive enhancement without stimulant effects
- Potential therapeutic for Alzheimer's and cognitive aging
- Enhances memory and learning
- Improves focus and concentration
- Increases mental energy and motivation
- Provides neuroprotection via BDNF and NGF upregulation
- Reduces cognitive decline
- May alleviate ADHD symptoms
- Supports recovery from brain injury and stroke
- Fast-acting — effects within 30–60 minutes
- Approved in Russia for cognitive disorders and stroke recovery
- Side Effects
- Generally well tolerated in animal studies
- Limited human clinical data
- Injection site reactions
- Potential mild fatigue at initiation
- Headache (rare, often from higher doses)
- Anxiety or overstimulation at high doses
- Sleep disruption if dosed too late
- Irritability (uncommon)
- Stacks With
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