← Back to Peptide Library

PE 22-28

Preclinical
Cognitive & brain

A seven-amino-acid fragment studied as an antidepressant — in mice, by one lab, never in a human.

What it is

PE 22-28 is a short piece of a human protein called sortilin. When the protein matures, a cap is trimmed off, and this peptide is a stretch of that discarded cap. It is the shortened form of a longer peptide called spadin, which the same lab described earlier. It is sold for mood and focus.

How it works

It blocks a potassium channel called TREK-1. In animal work, blocking that channel produces antidepressant-like behavior. In mouse tests, a single dose cut a standard measure of despair-like immobility roughly in half and increased the birth of new brain cells.

What people report

  • A single dose reduced immobility in a standard mouse depression test
  • Increased new-cell counts in the hippocampus of mice
  • Reported as far more potent and longer-lasting than its parent molecule
  • Sold into the mood and nootropic corner of the market

Typical use

None established. The plain peptide has only ever been given to mice, in single doses.

Dosing reference

Animal work used 3-4 mcg/kg by injection. There is no human reference dose. Verify against the primary literature.

Reference only — not a recommendation. Verify via primary sources.

Watch for

Despite the potency claims, both headline numbers were measured on modified versions of the molecule, not the plain peptide you might buy. No human has ever received it, and its effect reverses across a wide dose range in the source papers.

Educational content — not medical advice.