PE-22-28

What is PE-22-28?

PE-22-28 is a synthetic peptide analog of spadin, which is derived from the propeptide of sortilin. It acts by blocking TREK-1 potassium channels in the brain, a mechanism associated with rapid antidepressant effects. Unlike traditional antidepressants that take weeks to work, TREK-1 blockade has shown rapid mood improvement in preclinical models. Clinical biomarker studies have confirmed that sortilin-derived propeptide levels are altered in depression and change with treatment.

What PE-22-28 Is Investigated For

PE-22-28 is a synthetic spadin analog that blocks the TREK-1 potassium channel, investigated as a rapid-onset antidepressant, a neuroplasticity and BDNF-upregulating agent, and a candidate for stroke recovery and post-stroke depression. The strongest support is preclinical: multiple rodent studies show antidepressant-like behavioral effects within 1–4 days of dosing (distinctly faster than the 2–4 week onset of SSRIs), enhanced synaptogenesis, and neuroprotection in stroke models. Human biomarker work has independently confirmed that sortilin-derived propeptide levels are decreased in major depressive disorder and shift after electroconvulsive therapy — which validates the underlying TREK-1/sortilin pathway in human depression. The critical gap is that PE-22-28 itself has never been tested in a published human clinical trial of any phase: validation of a target pathway is not the same as validation of a specific compound that engages it, and pharmacokinetic, cardiovascular, and psychiatric-safety data in humans are entirely absent. Ketamine and esketamine remain the only validated fast-onset antidepressants in clinical use.

History & Discovery

PE-22-28 emerged from a research program led by Marc Borsotto, Catherine Heurteaux, and Michel Lazdunski at the Institut de Pharmacologie Moléculaire et Cellulaire (IPMC) in Valbonne, France. The program's starting point was TREK-1, a two-pore-domain potassium channel that — based on knockout mouse work from the same lab — appeared to play a central role in vulnerability to depression: TREK-1-deficient mice were strikingly resistant to depressive behavior in standard rodent assays. The Borsotto group identified spadin, a peptide cleaved from the propeptide region of sortilin (a receptor protein with roles in neurotrophin signaling and lipid handling), as an endogenous TREK-1 blocker. In rodent models, spadin produced antidepressant-like effects within days, in contrast to the several-week onset typical of SSRIs and SNRIs. PE-22-28 is a shortened, optimized analog of spadin — designed with improved metabolic stability, retained TREK-1 inhibition, and a similar fast-onset antidepressant profile in animal models. The translational arc has been notable on two fronts. First, biomarker work in human depression has confirmed that sortilin-derived propeptide levels are altered in patients with major depressive disorder and shift after electroconvulsive therapy, which validates the underlying TREK-1/sortilin pathway as relevant to human depression. Second, despite this, PE-22-28 itself has not advanced to human clinical trials. The compound exists in the published literature as a preclinical antidepressant tool and in the research-chemical market as a 'mood' peptide with no human evidence base.

How It Works

PE-22-28 blocks a specific potassium channel in the brain (TREK-1) that is linked to depression. By blocking this channel, it may rapidly improve mood and promote brain cell growth and connectivity.

PE-22-28 selectively inhibits TREK-1 (TWIK-related potassium channel-1), a two-pore domain potassium channel highly expressed in mood-regulating brain regions. TREK-1 knockout mice display a depression-resistant phenotype. Blockade increases neuronal excitability, promotes BDNF expression, enhances hippocampal neurogenesis, and increases serotonergic and noradrenergic neurotransmission. The peptide shows improved stability over the parent compound spadin.

Evidence Snapshot

Research Gaps & Open Questions

What the current literature has not yet settled about PE-22-28:

• 01Any human clinical trial — no published Phase I, II, or III study has tested PE-22-28 in humans for safety, pharmacokinetics, dose-response, or efficacy.
• 02Cardiovascular safety of TREK-1 blockade in humans — TREK-1 is expressed in cardiac and vascular tissues, and the long-term cardiovascular consequences of pharmacologic channel blockade are uncharacterized.
• 03Comparative efficacy vs. ketamine, esketamine, and other fast-acting antidepressants — the only validated rapid-onset antidepressants in humans work through different mechanisms; PE-22-28 has never been compared.
• 04Independent preclinical replication outside the originating Borsotto/IPMC program — replication in independent labs is sparse.
• 05Pharmacokinetics in humans — absorption, distribution, metabolism, and excretion have not been characterized in any species relevant to predicted human exposure at proposed doses.
• 06Long-term effects on BDNF, neurogenesis, and synaptic plasticity in chronic dosing — preclinical work has used short courses, and chronic neuroplastic consequences are unknown.

Forms & Administration

PE-22-28 is a research compound typically administered via injection in preclinical studies. Human dosing protocols do not exist. All injectable peptides should only be administered under the guidance of a qualified healthcare provider. Never self-administer without clinician oversight.

Dosing & Protocols

The ranges below reflect protocols commonly discussed in the literature and by clinicians — not a prescription. Actual dosing for any individual should be determined by a qualified healthcare provider who knows the patient.

PE-22-28 has never been tested in humans in a published clinical trial and is not approved for any indication anywhere. The fast-onset antidepressant profile in animal models is preclinical and does not constitute evidence of safety or efficacy in human depression. Self-administration as a 'mood' peptide carries entirely uncharacterized risk.

Timeline of Effects

Common Questions

Who PE-22-28 Is NOT For

Drug & Supplement Interactions

There are no published clinical drug-interaction studies for PE-22-28 in humans. What follows is mechanistic inference, not documented interaction data. The most plausible theoretical concerns involve other antidepressants and CNS-active medications. SSRIs, SNRIs, MAOIs, atypical antidepressants, and ketamine all act through pathways that intersect with TREK-1 biology in some way (TREK-1 modulates serotonergic neuron excitability, among other effects). Combined use is unstudied; theoretical risks include serotonin syndrome (with serotonergic agents), excessive mood effects, and unpredictable response. With antiarrhythmic drugs and any agent with QT-prolonging or potassium-channel-modulating activity, TREK-1 blockade introduces an additional cardiac electrophysiologic variable that has not been characterized in humans. With benzodiazepines and other GABAergic sedatives, additive CNS depression is plausible but unstudied. No specific concerns have been documented with cardiovascular, metabolic, or endocrine medications, but the absence of documentation reflects the absence of human use, not the absence of risk. Patients on any regular medication should not co-administer PE-22-28 without disclosure to their prescriber — and the responsible answer in most cases is not to use PE-22-28 at all.

Safety Profile

Legal Status

Regulatory status changes over time. Verify current local rules with a qualified professional.

Myths & Misconceptions