PE-22-28
Proenkephalin Fragment
PE-22-28 is a synthetic heptapeptide derived from the active region of Spadin, a naturally occurring peptide that functions as a specific antagonist of the TREK-1 potassium channel (KCNK2), a validated target for antidepressant therapy. By blocking TREK-1 channels, it produces rapid-onset antidepressant effects similar to those observed with SSRIs but within days rather than weeks, while also promoting hippocampal neurogenesis. Its primary research applications focus on treatment-resistant depression, cognitive enhancement, and neuroplasticity modulation.
Mechanism of Action
Fragment of proenkephalin that modulates opioid receptor signaling in adipose tissue. Promotes brown adipose tissue thermogenesis and white adipose tissue browning. Enhances uncoupling protein 1 (UCP1) expression, increasing non-shivering thermogenesis and energy expenditure.
Research Protocols
For research purposes only. Not medical advice.
Research protocols use 500mcg-1mg subcutaneously daily. Limited human data. Animal studies used varying doses. Often discussed alongside other fat-loss peptides. Cycles of 4-8 weeks.
Research Notes
Clinical Research Status
PE-22-28 is in preclinical research stages, building on the published work demonstrating Spadin and its analogs as a novel class of antidepressants acting through TREK-1 channel blockade. The parent compound Spadin was characterized by researchers at CNRS and University of Nice, with PE-22-28 representing an optimized shorter fragment with improved stability and blood-brain barrier penetration. No human clinical trials have been initiated specifically for PE-22-28, though the TREK-1 target has been validated in multiple preclinical depression models.
Key Published Findings
Research demonstrates that PE-22-28 produces antidepressant-like effects in mouse models (forced swim test, tail suspension test) within 4 days of administration, compared to 2-3 weeks required for SSRI onset of action. TREK-1 knockout mice display a depression-resistant phenotype identical to the effects produced by pharmacological blockade with PE-22-28 and related analogs. The compound has been shown to stimulate hippocampal neurogenesis and increase BDNF expression, providing a mechanistic basis for both its antidepressant and potential cognitive-enhancing effects through neuroplasticity promotion.
Safety Profile
Preclinical studies suggest good tolerability with no observed toxicity at effective antidepressant doses in animal models. TREK-1 channels are expressed in multiple tissues beyond the brain (heart, smooth muscle, adrenal gland), raising theoretical concerns about peripheral effects that have not been fully characterized. As a research compound without human trial data, the safety profile in humans including appropriate dosing, potential for dependence, and long-term effects on channel regulation remains undetermined.
Drug Interactions & Contraindications
Theoretical interactions exist with existing antidepressant medications (SSRIs, SNRIs, MAOIs) as combining multiple mechanisms affecting serotonergic and neuroplasticity pathways could produce unpredictable effects. TREK-1 channels play roles in neuroprotection during ischemia, so concurrent use with compounds affecting cerebrovascular function warrants caution. Individuals with cardiac arrhythmias should exercise caution given the expression of TREK-1 channels in cardiac tissue, though the degree to which PE-22-28 affects peripheral channels at therapeutic brain concentrations is unknown.
Comparison to Related Compounds
Spadin (the parent peptide) is a 17-amino-acid peptide with the same mechanism but poorer stability and shorter half-life compared to the optimized PE-22-28 fragment. Unlike SSRIs which require 2-4 weeks for therapeutic onset and carry sexual dysfunction and emotional blunting side effects, TREK-1 antagonism offers rapid-onset antidepressant action through a fundamentally different mechanism. Ketamine and its analogs also provide rapid antidepressant effects but through NMDA receptor antagonism with dissociative side effects and abuse potential that are not associated with TREK-1 blockade.
Community Observations
Users exploring PE-22-28 typically report noticeable mood improvements and cognitive clarity within 3-7 days of intranasal or subcutaneous administration at doses extrapolated from preclinical research (typically in the low microgram range). Reports suggest it produces a calm, clear-headed improvement in mood without the emotional numbing or sexual side effects commonly associated with SSRI medications. The research community notes that PE-22-28 represents one of the few peptide-based approaches to depression with a clearly validated molecular target, though sourcing verified high-purity material remains challenging due to its relative obscurity compared to mainstream research peptides.
Half-Life
~1-2 hours
Reconstitution
Bacteriostatic water (BAC)
Storage
Lyophilized
Refrigerate 2-8C up to 12 months.
Reconstituted
Refrigerate 2-8C. Use within 14 days.
US Legal Status
Also Known As
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