New — Free Peptide Starter Guide (2026): 13 chapters, 34 cited studies

Get it free
ToolsComparePE-22-28 vs AOD-9604

PE-22-28 vs AOD-9604

Side-by-side comparison of key properties, dosing, and research.

Cognitive Enhancement
PE-22-28
Fat Loss & Metabolic
AOD-9604
Summary
PE-22-28 is a synthetic analog of spadin derived from sortilin, designed to block TREK-1 potassium channels with rapid-onset antidepressant and neurogenic effects. It shows fast-acting depression relief (within 24 hours) and promotes hippocampal neurogenesis.
AOD-9604 is a modified fragment of human growth hormone (residues 177-191) with an additional tyrosine residue that significantly enhances bioavailability. Originally developed as an anti-obesity drug by Metabolic Pharmaceuticals, it stimulates lipolysis and inhibits lipogenesis without the diabetogenic effects of full GH.
Half-Life
Relatively short; CNS effects may persist due to neurogenic mechanisms
30-45 minutes injectable; longer with nasal spray formulation
Admin Route
SubQ, Intranasal
SubQ, Intranasal, Oral
Research
Typical Dose
200–400 mcg
300-600 mcg
Frequency
Once daily
Once daily
Key Benefits
  • Rapid-onset antidepressant effects (within 24 hours)
  • Promotes hippocampal neurogenesis
  • Improves cognitive performance and memory
  • Reduces anxiety and depressive behavior
  • Novel mechanism — does not act on serotonin/dopamine/GABA receptors directly
  • May help treatment-resistant depression
  • Neuroprotective effects
  • Selective fat loss without anabolic side effects
  • No effect on blood glucose or insulin resistance
  • Improved bioavailability over Fragment 176-191
  • GRAS (Generally Recognized As Safe) status in Australia
  • Potential cartilage repair and anti-inflammatory properties
  • Does not suppress natural GH production
Side Effects
  • Generally well tolerated in animal models
  • Limited human data available
  • Possible mild headache or transient mood changes at initiation
  • Injection site reactions (SC)
  • Localized injection site reactions
  • Headache (rare)
  • Hypoglycemia risk in combination with insulin (very rare)
Stacks With