P21

A peptide derived from the CDK5-activating cofactor p35, designed to inhibit pathological CDK5/p25 hyperactivity implicated in neuronal apoptosis after injury or in neurodegeneration.

Mechanism of action from published research — how the molecule behaves, not a claim about any product or any human-use effect.

Studied for neuroprotection in ischemic stroke and neurodegenerative disease models, including Alzheimer's and Parkinson's.

• Cognitive & moodStudied in memory, focus, mood, and neuroprotection research.

Preclinical / animal research — efficacy shown in rodent stroke and Parkinson's models (often via the related peptide 'TFP5'), with no identified human trials.

Where the science stands — an approved drug is not the same as the research-grade material a vendor sells, which is unregulated regardless.

• Independent purity. Look for a third-party COA (Janoshik or MZ) showing a measured purity — not just a number the vendor typed.
• Batch match. The strongest evidence is a certificate for the exact batch you’ll receive, attributed to this vendor — check the cross-verification on the listing.
• Vendor reputation. See how the vendor is talked about in the community before trusting a new name.

Research context only — VialGrade never gives dosing, medical, or human-use guidance.