---
canonical_name: PE-22-28
alternate_names: Mini-Spadin, PE 22-28, Minispadin
canonical_topic: PE-22-28 for Health & Longevity
short_topic_lc: pe_22_28
creation_date: 2026-1004-1009
creator_ai_fullname: Opus 5.5
ep_keywords: Spadin Analogs, TREK-1 Blockers, TREK-1 Inhibitors, Potassium Channel Blockers, Peptides
---

# PE-22-28 for Health & Longevity
<section id="top" markdown="1"></section>
Evidence Review created on 10/04/2026 using [AI4L](https://github.com/forever-healthy/AI4L) / Opus 5.5

**Also known as:** Mini-Spadin, PE 22-28, Minispadin

  
## Motivation

<!-- This motivation section was written last, after every other section of this review was complete, so that it reflects the full scope of what the record does and does not contain. -->

PE-22-28 is a laboratory-made peptide just seven amino acids long. It was derived from a short natural human peptide released when a sorting protein inside nerve cells is processed. Its only known target is a background potassium channel that helps keep nerve cells quiet, and the peptide blocks that channel.

Interest in this channel grew after mice bred without it were studied for mood-related behaviour, and after the natural parent peptide was identified and then shortened in search of more stable forms. PE-22-28 came out of that shortening work, one of the fragments screened for how tightly it holds the channel. Today it is sold by online suppliers and offered by some private clinics, and it is discussed in longevity circles alongside other peptides aimed at mood and brain function.

This review examines what the published record does and does not establish about PE-22-28: how it is thought to work, which effects have been measured and in which species, what is known about its safety, how it is being obtained and administered outside approved medicine, and where the record is silent.

**[Benefits](#expected-benefits) - [Risks](#potential-risks--side-effects) - [Protocol](#therapeutic-protocol) - [Conclusion](#conclusion)**

  
## Recommended Reading

High-level sources that explain what PE-22-28 is, how its target TREK-1 (a background potassium channel that keeps nerve cells harder to excite) is thought to work, and how the peptide is used outside research settings.

<!-- Real-time search performed 2026-10-02. Web search ("PE-22-28", "spadin", plus each priority expert's name) run via WebSearch; on-site searches run with d-browser browser_navigate + browser_snapshot against peterattiamd.com (?s=PE-22-28 -> "Nothing Found"), hubermanlab.com (site search for "PE-22-28" -> only unrelated PEA/polyethylene/RPE timestamps; the "Peptides: The Science, Uses & Safety" episode transcript contains no PE-22-28 or spadin mention), chriskresser.com (?s=PE-22-28 -> "There are no search results for that term"), foundmyfitness.com (search "spadin" -> 9 unrelated results, no PE-22-28 or spadin content), lifespan.io (?s=PE-22-28 and ?s=spadin -> "No Articles Found"), and lifeextension.com (d-browser blocked by Akamai; retrieved via d-proxy-2 scrape_as_markdown -> search page returns no matching article). PubMed searched for narrative reviews, editorials and primary research on PE-22-28, spadin and TREK-1. Systematic reviews and meta-analyses excluded per section scope; Grokipedia, Examine and ConsumerLab excluded; Wikipedia, forums and mainstream media excluded. -->

* [Fighting against depression with TREK-1 blockers: Past and future. A focus on spadin](https://pubmed.ncbi.nlm.nih.gov/30291907/) - Djillani et al., 2019

  Narrative review by the group that designed PE-22-28, tracing spadin's optimisation into shortened analogues and setting out the case for blocking TREK-1; the fullest single account of the peptide's rationale.

* [TREK-1 in central nervous system diseases](https://pubmed.ncbi.nlm.nih.gov/40539288/) - Chen et al., 2026

  Independent review weighing evidence that blocking TREK-1 helps the brain against evidence that activating it protects the brain, and noting mini-spadin's opposite effects at low and high doses.

* [Spadin Selectively Antagonizes Arachidonic Acid Activation of TREK-1 Channels](https://pubmed.ncbi.nlm.nih.gov/32317978/) - Ma & Lewis, 2020

  Independent electrophysiology study that challenges the simple pore-block model: spadin prevented fatty-acid activation of the channel rather than inhibiting it directly, which bears on how PE-22-28 is assumed to act.

* [PE-22-28 Peptide: Benefits, side effects, dosage details, and how it works](https://www.innerbody.com/pe-22-28-peptide) - Dan Min

  Consumer-facing overview documenting how the peptide is actually obtained and administered outside research settings, including reported dose ranges and the research-grade versus pharmaceutical-grade distinction.

Only four items are listed because no further source discusses PE-22-28 or its mechanism in substantial depth; the list has not been padded with pages that merely catalogue the compound.

No content from the priority platforms (Rhonda Patrick, Peter Attia, Andrew Huberman, Chris Kresser, Life Extension Magazine, Lifespan.io) could be found: each site's own search returns nothing for PE-22-28 or spadin, and web searches pairing each name with the compound return no matching page.

Conflict of interest, named here at first citation: spadin, PE-22-28 and the shortened analogues were discovered, named and characterised almost entirely by one laboratory (Mazella, Borsotto, Heurteaux and colleagues, CNRS / Institut de Pharmacologie Moléculaire et Cellulaire, Nice), and the Centre National de la Recherche Scientifique and Université de Nice Sophia Antipolis hold the granted patent covering these peptides for depression ([US11220527B2](https://patents.google.com/patent/US11220527B2/en), active to 2037). Those parties therefore have a direct financial interest in the compound's adoption. The consumer pages cited in this review sit on commercial health sites, a commercial interest of the opposite kind.

  
## Grokipedia

<!-- grokipedia.com searched directly 2026-10-02. Tier 1 (d-browser, browser_navigate to https://grokipedia.com/search?q=PE-22-28 then browser_snapshot) returned the site's search results, with a dedicated "PE-22-28" article as the first hit; no further tier was needed. The article page itself was then loaded with d-browser and read. -->

* [PE-22-28](https://grokipedia.com/page/PE-22-28)

  Gives the sequence, molecular properties, binding data and preclinical findings in one place, and separates the peptide's measured pharmacology from the therapeutic applications that have only been proposed.

  
## Examine

<!-- examine.com searched directly 2026-10-02. Tier 1 (d-browser) returned a Vercel "Security Checkpoint" bot wall. Tier 2 (d-fetch) returned HTTP 429. Tier 3 (d-proxy-1, browser_navigate to https://examine.com/search/?q=PE-22-28 then browser_snapshot) loaded the genuine search page, which reads "Sorry, there are no search results for PE-22-28." The same tier was used for the query "spadin", which returned only one unrelated study summary about micronutrient intake in Spain. -->

No Examine article for PE-22-28 exists.

Examine covers dietary supplements and nutrients that are sold legally for human consumption; PE-22-28 is an unapproved research peptide, which is outside that scope.

  
## ConsumerLab

<!-- consumerlab.com searched directly 2026-10-02. Tier 1 (d-browser, browser_navigate to https://www.consumerlab.com/search/?q=PE-22-28 then browser_snapshot) loaded the genuine search page; it returned only unrelated items (walnuts, Qualia Mind, recall notices) matched on the fragment "PE 22 28", and no article on the peptide. The query "spadin" on the same tier returned "Sorry, we didn't find any results for spadin." No further tier was needed. -->

No ConsumerLab article for PE-22-28 exists.

ConsumerLab tests products that can be bought as supplements; PE-22-28 is not sold as a supplement and is not an approved medicine, so it falls outside the organisation's testing programme.

  
## Systematic Reviews

<!-- PubMed searched 2026-10-02 via d-pubmed pubmed_search_articles: ("PE 22-28" OR "PE22-28" OR "mini-spadin" OR spadin OR "sortilin-derived peptide") AND (systematic review OR meta-analysis) returned 2 records, both about dementia cohorts and unrelated to the peptide. (TREK-1 OR KCNK2 OR "two-pore domain potassium") AND (systematic review[pt] OR meta-analysis[pt] OR "systematic review"[ti] OR "meta-analysis"[ti]) returned 4 records, all genetic-association or expression analyses of other channels. Europe PMC searched for the same terms with the same outcome. -->

No systematic reviews or meta-analyses for PE-22-28 were found on PubMed as of October 2, 2026.

The trade-off at the centre of this review — a possible rapid mood effect set against the consequences of blocking a channel that also serves the heart, pancreas, eye and immune system — is unrepresented on both sides: no systematic review or meta-analysis covers either the claimed effect or the principal risk.

  
## Mechanism of Action

PE-22-28 is a seven-amino-acid peptide, glycine-valine-serine-tryptophan-glycine-leucine-arginine ([PubChem CID 165437303](https://pubchem.ncbi.nlm.nih.gov/compound/165437303)), taken from positions 22 to 28 of the propeptide released when sortilin is processed; spadin is a longer fragment of the same propeptide.

Its target is TREK-1 (a background potassium channel, encoded by the KCNK2 gene, that lets potassium leave the cell and so makes nerve cells harder to excite). Blocking it leaves neurons more responsive to signals. In rodents this has been tied to faster firing of serotonin-producing neurons and to new hippocampal cell growth ([Mazella et al., 2010](https://pubmed.ncbi.nlm.nih.gov/20405001/)).

Pharmacological properties: in cells carrying the human channel, PE-22-28 half-blocked TREK-1 at 0.12 nanomolar — its IC50, the concentration giving half-maximal block — against 40–60 nanomolar for spadin, with no measurable action on TREK-2, TRAAK, TRESK or TASK-1, related potassium channels, nor on hERG, a heart potassium channel whose blockade can provoke dangerous rhythms ([Djillani et al., 2017](https://pubmed.ncbi.nlm.nih.gov/28955242/)). The channel is found in brain, heart, smooth muscle, pancreatic beta cells and prostate ([Djillani et al., 2019](https://pubmed.ncbi.nlm.nih.gov/31031627/)). Blood peptidases (enzymes breaking proteins) cut it, not liver enzymes; serum stability is short, yet its analogues' effects in mice lasted 14–23 hours.

Competing accounts exist: one treats the peptide as a direct blocker of the open channel, while an independent study found spadin did not inhibit open channels, only their activation by arachidonic acid ([Ma & Lewis, 2020](https://pubmed.ncbi.nlm.nih.gov/32317978/)) — in frog egg cells carrying the mouse channel, not the human channel used originally. A third reports activation of TREK-1 at very low doses ([Pietri et al., 2019](https://pubmed.ncbi.nlm.nih.gov/31325429/)).

  
## Historical Context & Evolution

TREK-1 was not originally studied for mood, but as a channel governing neuroprotection and anaesthetic sensitivity: mice lacking the gene proved more vulnerable to seizures and to brain and spinal-cord ischaemia (restricted blood flow), and resistant to anaesthesia ([Heurteaux et al., 2004](https://pubmed.ncbi.nlm.nih.gov/15175651/)). Two years later the same laboratory reported those mice behaving like animals already treated with an antidepressant across five behavioural models, with stronger serotonin signalling and more new hippocampal cells ([Heurteaux et al., 2006](https://pubmed.ncbi.nlm.nih.gov/16906152/)). That finding, not a clinical observation, turned the channel into a drug target.

The search for a blocker produced spadin, a 17-amino-acid fragment of the sortilin propeptide, presented as a natural molecule acting within four days rather than the three to four weeks of standard antidepressants ([Mazella et al., 2010](https://pubmed.ncbi.nlm.nih.gov/20405001/)). Its effect faded beyond roughly seven hours, so the group tried reversed-sequence analogues ([Veyssiere et al., 2015](https://pubmed.ncbi.nlm.nih.gov/25080852/)) and then shortened fragments from spadin's own blood breakdown products, yielding PE-22-28 ([Djillani et al., 2017](https://pubmed.ncbi.nlm.nih.gov/28955242/)).

Opinion has not settled. The early framing — potent, selective, free of the channel's known liabilities — came from the patent-holding laboratory. Since then an independent group has questioned how the peptide acts, cardiac and metabolic roles for TREK-1 have been described, and a 2026 review sets the case for blocking the channel against evidence that activating it protects brain tissue ([Chen et al., 2026](https://pubmed.ncbi.nlm.nih.gov/40539288/)). Treating this as closed would misstate the record: none of it has been tested in people, and the peptide reached consumers through online suppliers, not trials.

  
## Expected Benefits

<!-- Dedicated benefit search performed 2026-10-02 before this section was written. d-pubmed pubmed_search_articles run on: "PE 22-28" OR "PE22-28" OR "mini-spadin" OR spadin (81 records); "sortilin-derived peptide(s)" OR "spadin analog(s)" OR "G/A-PE 22-28" (12 records); spadin[tiab] AND (depression OR TREK-1 OR antidepressant) (40 records), which returned the independent rat replication of Qi 2018 reported below; Heurteaux[au] AND TREK-1 AND (depression-resistant OR neuroprotection OR knockout). Full text of Djillani 2017 retrieved via pubmed_fetch_fulltext. Europe PMC searched for the same terms including preprints (14 records). Searches were run deliberately for null and opposite-direction results: Ma & Lewis 2020 (no direct inhibition of open or chemically activated channels), Pietri 2019 (opposite channel effect at low dose), Kim 2025 (greater fat gain and worse glucose tolerance in channel-deleted mice) were found this way and are reported here or in Potential Risks. No human efficacy study of PE-22-28, spadin or any analogue was found in PubMed, Europe PMC or ClinicalTrials.gov. -->

### High 🟩 🟩 🟩

No benefit reaches High: there is no human clinical endpoint and no validated human surrogate measurement for PE-22-28 at all, let alone one replicated by independent research groups — the entire record is rodent behaviour and cell-culture assays.

### Medium 🟩 🟩

No benefit reaches Medium: there is no single human trial and no controlled human observational data for PE-22-28; every measured outcome comes from mice, rats or cultured cells.

### Low 🟩

### Speculative 🟨

#### Rapid Antidepressant-Like Behaviour in Rodents

Mice given 3–4 micrograms per kilogram showed shorter immobility after four days ([Djillani et al., 2017](https://pubmed.ncbi.nlm.nih.gov/28955242/)); an independent group saw the same with parent peptide spadin in rats ([Qi et al., 2018](https://pubmed.ncbi.nlm.nih.gov/29952548/)). Animal behaviour only.

#### New Hippocampal Cells and More Synaptic Protein

Four days of treatment roughly doubled newly labelled cells in the mouse hippocampus, and cortical neurons raised PSD-95, a protein marking new synapse formation ([Djillani et al., 2017](https://pubmed.ncbi.nlm.nih.gov/28955242/)). Cell and animal work only.

#### Recovery After Experimental Stroke

In mice with induced focal ischaemia, mini-spadin limited weight loss, delayed dopamine-neuron loss, improved motor and memory deficits and prevented later depression-like behaviour ([Pietri et al., 2019](https://pubmed.ncbi.nlm.nih.gov/31325429/)). Animal model only.

#### Pancreatic Beta-Cell Survival and Proliferation

In cultured insulin-producing cells, the parent propeptide and mini-spadin blocked death from an inflammatory signal and switched on a survival pathway; mini-spadin also drove cell division ([Daziano et al., 2021](https://pubmed.ncbi.nlm.nih.gov/33737242/)). Cell assays only.

#### Lower Brain Inflammation Signalling in Rats

In rats under chronic unpredictable stress, spadin — the parent peptide, not PE-22-28 — reduced depression-like behaviour and inflammatory signalling through NF-κB, a protein switch for inflammation genes ([Cong et al., 2023](https://pubmed.ncbi.nlm.nih.gov/36670238/)). Animal work only.

  
## Benefit-Modifying Factors

* **Genetic variation in the target and its partner:** Variants in KCNK2 (the TREK-1 gene) alter channel behaviour, and loss of SORT1 (the sortilin gene) by itself changes channel surface expression and lowers depression-like behaviour in mice ([Moreno et al., 2018](https://pubmed.ncbi.nlm.nih.gov/30127743/)). No human pharmacogenetic data exist.

* **Baseline biomarker levels:** Serum levels of the natural sortilin propeptide are lower in people with major depressive disorder and rise with successful treatment ([Devader et al., 2017](https://pubmed.ncbi.nlm.nih.gov/27838145/)). Whether a low baseline predicts more or less response to the synthetic fragment has never been tested.

* **Sex-based differences:** Every rodent efficacy experiment behind this compound used male animals, so sex differences in response are entirely unexamined. No sex-stratified data exist for the peptide or for spadin.

* **Pre-existing health conditions:** The peptide worked both in healthy animals and in animals made depression-like by seven weeks of corticosterone, a stress hormone, with no comparison between the two ([Djillani et al., 2017](https://pubmed.ncbi.nlm.nih.gov/28955242/)). No human condition has been studied.

* **Age-related considerations:** All published experiments used young adult rodents. Nothing is known about response in middle or later life, including the older end of the health- and longevity-oriented age range, where channel expression and brain plasticity both differ.

  
## Potential Risks & Side Effects

<!-- Dedicated side-effect search performed 2026-10-02 before this section was written. Drug reference sources were checked first: the compound appears in no prescribing information, and the FDA 503A bulk drug substances page (loaded with d-browser) contains no entry for PE-22-28 or spadin, so no label or monograph exists to search. PubMed searched via d-pubmed for: spadin safety and side effects; (TREK-1 OR KCNK2) AND (ventricular tachycardia OR atrial fibrillation OR arrhythmia) AND (mutation OR deficient OR knockout); (TREK-1 OR K2P2.1 OR KCNK2) AND atrial fibrillation, which returned the human atrial expression and porcine gene-transfer work of Lugenbiel 2017 reported below; TREK-1 sinoatrial node membrane excitability; TREK-1 pain, epilepsy, ischaemia, blood-brain barrier, inflammasome, adipocyte, trabecular meshwork and pulmonary artery smooth muscle (which returned Csaki 2024, reported below); (TREK-1 OR KCNK2 OR K2P2.1) AND (cancer OR tumor OR prostate OR proliferation OR carcinoma), which returned Wang 2023 on KCNK2 silencing promoting carcinoma cell growth, reported below. Searches for null and lower-risk findings returned Moha Ou Maati 2012 (no effect of spadin on pain, seizures, ischaemia, glycaemia, blood pressure or cardiac repolarising current) and the hERG data in Djillani 2017; both are cited below against the conflicting findings. Consumer and vendor pages were reviewed for reported adverse events; none report any. -->

### High 🟥 🟥 🟥

No risk reaches High: there is no documented human adverse event, no human clinical endpoint and no validated human surrogate measurement for PE-22-28 from any research group — nobody has reported giving it to a person under observation.

### Medium 🟥 🟥

No risk reaches Medium: there is no single human trial and no controlled human observational data on harms from PE-22-28; the record is gene-deletion work, animal dosing and cell assays.

### Low 🟥

### Speculative 🟨

#### Lower Seizure Threshold ⚠️ Conflicted

Basis is gene deletion, not the peptide: channel-null mice seize readily ([Heurteaux et al., 2004](https://pubmed.ncbi.nlm.nih.gov/15175651/)). Spadin did not worsen chemically induced seizures ([Moha Ou Maati et al., 2012](https://pubmed.ncbi.nlm.nih.gov/21807005/)). Net: unconfirmed theoretical risk.

#### Heightened Pain Sensitivity ⚠️ Conflicted

Gene-deletion basis: mice lacking the channel are more pain-sensitive ([Alloui et al., 2006](https://pubmed.ncbi.nlm.nih.gov/16675954/)), yet spadin left pain responses unchanged ([Moha Ou Maati et al., 2012](https://pubmed.ncbi.nlm.nih.gov/21807005/)). Net: deletion predicts it, blockade has not reproduced it.

#### Worse Outcome From Brain Ischaemia ⚠️ Conflicted

Animal data only: channel-deleted mice suffer larger infarcts (dead tissue) ([Heurteaux et al., 2004](https://pubmed.ncbi.nlm.nih.gov/15175651/)), while low-dose mini-spadin activated the channel and shrank them ([Pietri et al., 2019](https://pubmed.ncbi.nlm.nih.gov/31325429/)). Net: risk attaches to higher blocking doses.

#### Slow Heart Rate and Pauses ⚠️ Conflicted

Heart-specific channel deletion caused bradycardia (abnormally slow heart rate) and pauses in mice ([Unudurthi et al., 2016](https://pubmed.ncbi.nlm.nih.gov/27098968/)); spadin left pulse and cardiac repolarising currents unchanged ([Moha Ou Maati et al., 2012](https://pubmed.ncbi.nlm.nih.gov/21807005/)). Net: unresolved.

#### Worse Cardiac Remodelling Under Pressure Load

Heart-specific channel deletion worsened chamber dilation and prolonged the QT and QRS intervals, measures of electrical recovery and conduction, after pressure overload in mice ([Johnson et al., 2025](https://pubmed.ncbi.nlm.nih.gov/40387641/)). Gene-deletion basis, not the peptide.

#### Atrial Rhythm Disturbance From Lower Channel Function

Atrial tissue from people with chronic atrial fibrillation and heart failure carried roughly 80% less channel message, and gene transfer restored rhythm in pigs ([Lugenbiel et al., 2017](https://pubmed.ncbi.nlm.nih.gov/28005193/)). Expression and gene-transfer basis, not the peptide.

#### Raised Pulmonary Blood-Vessel Tone

In human lung-artery muscle cells, spadin — the parent peptide, not PE-22-28 — blocked the channel that keeps those vessels relaxed ([Csáki et al., 2024](https://pubmed.ncbi.nlm.nih.gov/38807478/)). Isolated human cells only.

#### Hypoglycaemia (Low Blood Sugar) From Increased Insulin Release ⚠️ Conflicted

Spadin (the parent peptide) amplified insulin secretion in cells and mice ([Hivelin et al., 2016](https://pubmed.ncbi.nlm.nih.gov/28105440/)), yet the same group found blood sugar unchanged ([Moha Ou Maati et al., 2012](https://pubmed.ncbi.nlm.nih.gov/21807005/)). Net: insulin rose, glucose did not.

#### Easier Immune-Cell Entry Into the Brain

Blocking the channel increased white-cell passage across cultured brain-barrier cells, and channel-deleted mice developed more severe multiple-sclerosis-like disease ([Bittner et al., 2013](https://pubmed.ncbi.nlm.nih.gov/23933981/)). Basis is cell and gene-deletion work, not the peptide.

#### Raised Pressure Inside the Eye

In human eye-drainage cells, spadin — the longer parent peptide, not PE-22-28 — blocked the channel's pressure-triggered response, the machinery setting intraocular pressure (fluid pressure inside the eye) ([Yarishkin et al., 2018](https://pubmed.ncbi.nlm.nih.gov/30446509/)). Isolated cells only.

#### More Fat Accumulation and Poorer Glucose Tolerance

Spadin — the parent peptide, not PE-22-28 — increased fat-cell differentiation in culture, and channel-deleted mice on a high-fat diet gained more fat mass with worse glucose tolerance ([Kim et al., 2025](https://pubmed.ncbi.nlm.nih.gov/40057491/)). Gene deletion plus cell work.

#### Unchecked Cell Growth in Tissues Carrying the Channel

Basis is gene and cell work, not the peptide: silencing KCNK2 promoted oesophageal cancer cell growth ([Wang et al., 2023](https://pubmed.ncbi.nlm.nih.gov/37014157/)), and mini-spadin drove beta-cell division ([Daziano et al., 2021](https://pubmed.ncbi.nlm.nih.gov/33737242/)). No tumour study exists.

#### Harm From Unverified Product Identity, Purity or Sterility

No adverse event is reported for this peptide. Basis is testing of comparable peptides sold without prescription: purity 7.7–14.4% against 99% claimed, endotoxin (bacterial fever-causing debris) in every sample ([Ashraf et al., 2024](https://pubmed.ncbi.nlm.nih.gov/39509151/)).

#### Unknown Immune Reaction to the Peptide

Repeated exposure to a synthetic peptide can provoke antibodies that neutralise it or cause reactions; antibodies against TREK-1 are themselves under study in people ([NCT06943365](https://clinicaltrials.gov/study/NCT06943365)). Mechanistic reasoning only; no immunogenicity testing published.

  
## Risk-Modifying Factors

* **Genetic variation in the channel:** A KCNK2 mutation making TREK-1 sodium-permeable caused right ventricular outflow tract tachycardia, a rhythm disturbance arising where the heart's right chamber exits ([Decher et al., 2017](https://pubmed.ncbi.nlm.nih.gov/28242754/)). Carriers of such variants are an unstudied population.

* **Baseline biomarker levels:** Low fasting glucose or a history of reactive low blood sugar would amplify the insulin-release signal seen in animals; raised baseline intraocular pressure would matter for the eye-cell finding. Neither threshold has been quantified in people.

* **Sex-based differences:** No sex-stratified safety data exist. All rodent dosing used male animals, so differences in peptide clearance, cardiac repolarisation and hormonal context are untested.

* **Pre-existing health conditions:** Epilepsy, bradycardia or conduction disease, type 1 or type 2 diabetes on insulin-releasing medication, glaucoma, autoimmune central nervous system disease, a history of cancer and recent stroke each map onto a specific preclinical signal above.

* **Age-related considerations:** Resting heart rate falls and sinus-node reserve declines with age, and glaucoma and impaired glucose tolerance both become more common, so the cardiac, eye and metabolic signals are more consequential at the older end of the target range.

  
## Key Interactions & Contraindications

<!-- Dedicated interaction search performed 2026-10-02 before this section was written. d-pubmed pubmed_search_articles run for spadin and PE 22-28 combined with "drug interaction" and "pharmacokinetics": no human interaction or pharmacokinetic study of either peptide exists. Searches for the channel's known modulators returned the published in-vitro interaction data used below (Ma & Lewis 2020 on arachidonic acid; Lauritzen 2000 and Heurteaux 2004 on polyunsaturated fatty acids and volatile anaesthetics; Mazella 2010 and Djillani 2019 on fluoxetine's weak block of the same channel; Chen 2026 on caffeine and theophylline inhibiting the channel through cyclic AMP; Vallee 2016 on combined fluoxetine and spadin). Supplements were searched separately, which returned Ren 2021 on quercetin activating the channel through protein kinase C. Over-the-counter medicines were searched separately, which returned the caffeine and theophylline data; no over-the-counter analgesic, antihistamine or decongestant interaction is reported for either peptide. Everything else below is inferred from mechanism and is marked theoretical. Thresholds: no product label, guideline or trial exclusion criteria exist for this compound, so populations below are named as general categories without numeric cut-offs. -->

* **Selective serotonin reuptake inhibitors — the most widely used antidepressants (fluoxetine, sertraline, escitalopram):** Fluoxetine also blocks TREK-1, though weakly (about 19 micromolar) ([Djillani et al., 2019](https://pubmed.ncbi.nlm.nih.gov/30291907/)). Additive channel blockade and additive serotonin effect. Severity: caution (theoretical). Consequence: excess serotonin signalling.

* **Polyunsaturated fatty acid supplements (fish oil, flaxseed oil, alpha-linolenic acid):** These open TREK-1 and are the channel's main natural activators ([Lauritzen et al., 2000](https://pubmed.ncbi.nlm.nih.gov/10775263/)); spadin specifically prevented arachidonic-acid activation ([Ma & Lewis, 2020](https://pubmed.ncbi.nlm.nih.gov/32317978/)). Severity: monitor (theoretical). Consequence: mutual blunting.

* **Quercetin and other plant flavonoid supplements:** Quercetin activates TREK-1 by inhibiting protein kinase C, an enzyme regulating the channel, and spadin partly reversed its effects in mice ([Ren et al., 2021](https://pubmed.ncbi.nlm.nih.gov/33908633/)). Severity: monitor (theoretical). Consequence: mutual blunting at the shared target.

* **Volatile anaesthetics — inhaled gases used for surgical anaesthesia (sevoflurane, isoflurane, desflurane):** These open the same channel, and animals lacking it resist anaesthesia ([Heurteaux et al., 2004](https://pubmed.ncbi.nlm.nih.gov/15175651/)). Severity: caution (theoretical). Consequence: unpredictable anaesthetic depth, which makes disclosure before planned surgery the relevant step.

* **Insulin and insulin-releasing medicines (insulin, glipizide, glyburide, repaglinide):** The parent peptide amplified insulin secretion in cells and in mice ([Hivelin et al., 2016](https://pubmed.ncbi.nlm.nih.gov/28105440/)). Severity: caution (theoretical). Consequence: low blood sugar, with the usual sweating, tremor and confusion.

* **Glucose-lowering supplements (berberine, chromium picolinate, bitter melon, cinnamon extract):** Additive with the insulin-release signal above. Severity: monitor (theoretical). Consequence: low blood sugar, most likely when exposure is combined with fasting or endurance exercise.

* **Riluzole:** An approved drug that activates TREK-1 and was used to protect brain tissue in animals ([Bittner et al., 2013](https://pubmed.ncbi.nlm.nih.gov/23933981/)). Severity: monitor (theoretical). Consequence: opposing actions at the shared target, with net effect unpredictable.

* **Antiseizure medicines (levetiracetam, lamotrigine, valproate):** Channel deletion lowers seizure threshold, so blockade could in principle oppose seizure control, although spadin did not worsen seizures in mice. Severity: caution (theoretical). Consequence: breakthrough seizure.

* **Over-the-counter stimulants (caffeine tablets, theophylline preparations):** Both inhibit TREK-1 by raising cyclic AMP, a cell signalling messenger, so they act in the same direction as the peptide ([Chen et al., 2026](https://pubmed.ncbi.nlm.nih.gov/40539288/)). Severity: caution (theoretical). Consequence: additive excitability and lower seizure threshold.

* **Other interventions — intermittent fasting, ketogenic eating (a very low carbohydrate diet), prolonged endurance sessions:** All lower circulating glucose independently. Severity: monitor (theoretical). Consequence: additive low blood sugar given the insulin-release signal; separating exposure from long fasted sessions is the mitigating step.

* **Mitigating actions where an interaction is suspected:** No dose reduction or timing schedule has been studied. Available steps are separating fatty-acid supplements from dosing by several hours, checking fasting glucose when combined with glucose-lowering agents, and disclosing use before anaesthesia.

**Populations who should avoid PE-22-28:**

* Anyone with epilepsy or a prior unprovoked seizure (no numeric threshold is given by any source)
* Anyone with bradycardia, sinus-node disease (a failing natural pacemaker) or a cardiac conduction disorder (delayed electrical signalling in the heart)
* Carriers of a known KCNK2 variant, and anyone with unexplained ventricular arrhythmia
* People using insulin or insulin-releasing medicines, and anyone with recurrent low blood sugar
* People with glaucoma or raised intraocular pressure
* People with an autoimmune disease of the central nervous system, such as multiple sclerosis
* Anyone with a current or past cancer, given the unquantified proliferative signal
* People who are pregnant or breastfeeding, and anyone under 18
* Anyone within the recovery period after a stroke, where the animal data point to opposite effects at different doses

  
## Risk Mitigation Strategies

Doses, timings and thresholds below follow common practice for an unstudied compound unless cited; no product label, guideline or trial provides a threshold for this peptide.

* **Exposure as a first-in-human event:** Because no person has been dosed under published observation, the only defensible framing is an uncontrolled single-subject experiment. This mitigates the core risk of acting as though a safety profile exists when none does.

* **Material verification before any exposure:** The relevant documentation is a lot-specific certificate of analysis with identity by mass spectrometry, purity above 98% by high-performance liquid chromatography, and endotoxin below 0.5 units per milligram. Mitigates contaminated-product harm.

* **Starting far below reported amounts, with slow escalation:** Reported human-use amounts span 2–10 milligrams ([Innerbody](https://www.innerbody.com/pe-22-28-peptide)); beginning at roughly a tenth of the low end and holding each step for one week limits the size of any unexpected reaction.

* **Fasting glucose before and during use:** A fasting glucose measurement at baseline, at four weeks, then every three to six months addresses the insulin-release signal seen in cells and mice ([Hivelin et al., 2016](https://pubmed.ncbi.nlm.nih.gov/28105440/)). Mitigates unrecognised low blood sugar.

* **Resting electrocardiogram at baseline:** An electrocardiogram (a recording of the heart's electrical activity) before first exposure gives a personal comparison for heart rate and rhythm, addressing the bradycardia and sinus-pause signal from heart-specific channel deletion.

* **Baseline intraocular pressure where eye disease is present:** One pre-exposure reading, repeated at three months, addresses the eye-drainage-cell finding. Mitigates silent pressure rise, which causes no symptoms until vision is already affected.

* **Immediate cessation at any unexplained event:** A seizure, faint, slow pulse or new visual symptom is grounds for stopping rather than reducing. Mitigates a signal that preclinical data flag but no human study has bounded.

* **Separation of exposure from prolonged fasting or long endurance sessions:** Keeping dosing away from fasted training by several hours mitigates additive low blood sugar, the most plausible near-term adverse event given the animal insulin data.

* **Disclosure to every treating clinician:** Naming the peptide before surgery, before starting an antidepressant and before any glucose-lowering medicine is changed mitigates the anaesthetic, serotonin and hypoglycaemia interactions listed above.

  
## Therapeutic Protocol

No standard protocol exists, because no clinical trial, guideline or product label covers this peptide. What follows separates the published animal regimen from amounts reported in private practice. Parameters without a citation — timing, cycling, titration steps — reflect common practice rather than evidence.

* **Published animal regimen:** 3.0 micrograms per kilogram daily by intraperitoneal injection (into the abdominal cavity), or 1 milligram per kilogram by gavage (tube into the stomach), for four days ([Djillani et al., 2017](https://pubmed.ncbi.nlm.nih.gov/28955242/)). The only validated dose.

* **Amounts reported in private practice:** Single doses of 2–10 milligrams, adjusted by the prescribing clinician, are described for human use ([Innerbody](https://www.innerbody.com/pe-22-28-peptide)). No trial supports these figures, and they are not convertible from the rodent dose.

* **Competing route approaches:** Intranasal spray and subcutaneous injection are both described, the first chosen to bypass poor oral absorption ([Innerbody](https://www.innerbody.com/pe-22-28-peptide)). Oral dosing worked in mice only at a much higher dose. None has been compared in people.

* **Competing conventional approach:** Established antidepressant medicines and psychotherapy have human outcome evidence this peptide lacks entirely. Presenting the peptide and the conventional route side by side reflects the evidence gap rather than a preference between them.

* **Who popularised each approach:** The animal regimen comes from the CNRS laboratory in Nice that discovered and patented these peptides; the milligram-scale intranasal and subcutaneous approach comes from private peptide clinics and telehealth providers, not from a named researcher.

* **Best time of day:** Morning dosing is the usual practice reported for intranasal use, chosen by analogy with activating compounds. The animal experiments did not vary dosing time, so no evidence bears on this.

* **Expected half-life:** Serum stability is short, measured in minutes to an hour. Behavioural effect in mice outlasted that, with half-effect times of 14–23 hours for the analogues ([Djillani et al., 2017](https://pubmed.ncbi.nlm.nih.gov/28955242/)). No human pharmacokinetic measurement exists.

* **Single versus split dosing:** Every published experiment used a single daily dose. The long duration of effect relative to serum stability gives no mechanistic reason to split, and no comparison of split dosing has been run.

* **Genetic polymorphisms affecting dose choice:** KCNK2 variants that alter channel gating and SORT1 loss that lowers channel surface expression ([Moreno et al., 2018](https://pubmed.ncbi.nlm.nih.gov/30127743/)) would both be expected to shift the dose-response. No pharmacogenetic testing is available for this compound.

* **Sex-based differences in response:** Unknown. All dosing experiments used male rodents, so no sex-specific dose adjustment can be grounded in evidence.

* **Age-related considerations:** No experiment used aged animals. Slower peptide clearance, lower sinus-node reserve and higher baseline eye pressure at the older end of the target range all argue for the lowest starting amount, not a standard one.

* **Baseline biomarkers influencing response:** Serum sortilin propeptide level tracks depressive state in people ([Devader et al., 2017](https://pubmed.ncbi.nlm.nih.gov/27838145/)), but the assay is a research method and no study links it to response to the synthetic fragment.

* **Pre-existing conditions influencing response:** The peptide worked in healthy animals and in animals made depression-like by prolonged corticosterone, with no comparison between the two ([Djillani et al., 2017](https://pubmed.ncbi.nlm.nih.gov/28955242/)). Whether a stressed or unstressed human baseline changes response is untested.

  
## Discontinuation & Cycling

* **Lifelong or short-term:** Every published regimen is short — four days to a few weeks. Nothing supports continuous long-term use, and no animal experiment ran long enough to describe what sustained channel blockade does.

* **Known withdrawal effects:** None reported. No animal study tracked behaviour after stopping, and no human has been observed through discontinuation, so absence of reports is absence of data rather than evidence of a clean stop.

* **Tapering:** No taper protocol exists and none is mechanistically indicated for a peptide cleared within hours. The relevant uncertainty is whether channel expression adapts upward during exposure, which has not been measured.

* **Cycling for sustained effect:** Commonly reported practice is four to eight weeks of use followed by two to four weeks off. No experiment has compared continuous with cycled exposure, so the rationale is caution about unmeasured adaptation, not efficacy data.

* **Stopping abruptly when a signal appears:** Because the plausible adverse signals are neurological, cardiac and metabolic rather than withdrawal-prone, immediate cessation rather than a gradual reduction is the practical response to any unexplained event.

  
## Sourcing and Quality

* **No legitimate supply route exists:** PE-22-28 is not an approved medicine and appears on no FDA list of bulk substances eligible for pharmacy compounding ([FDA, bulk drug substances under section 503A](https://www.fda.gov/drugs/human-drug-compounding/bulk-drug-substances-used-compounding-under-section-503a-fdc-act)). A licensed compounding pharmacy therefore cannot lawfully prepare it.

* **Research-grade is not human-grade:** Material sold for laboratory use may contain substantial fillers and impurities and is not intended for human consumption, whereas pharmaceutical-grade peptide means roughly 99% purity ([Innerbody](https://www.innerbody.com/pe-22-28-peptide)). Vials shipped by online vendors are the former.

* **What to look for in documentation:** A batch-specific certificate of analysis naming the lot; identity confirmed by mass spectrometry against the sequence glycine-valine-serine-tryptophan-glycine-leucine-arginine; purity by high-performance liquid chromatography; and explicit endotoxin and sterility results, not a generic claim.

* **Why testing matters here specifically:** In products of this kind sold without prescription, measured purity ran 7.7–14.4% against 99% claimed, and endotoxin was present in every sample ([Ashraf et al., 2024](https://pubmed.ncbi.nlm.nih.gov/39509151/)). A vendor claim without a lot-specific report carries no information.

* **Reputable brands:** None can be named. No FDA-registered manufacturer supplies this peptide for human use and no third-party certification programme covers it, so any brand claim rests on the seller's own assertion.

* **Formulation considerations:** Freeze-dried powder reconstituted in bacteriostatic water is the described injectable form, while the intranasal product is sold ready to use ([Innerbody](https://www.innerbody.com/pe-22-28-peptide)). Avoiding vigorous shaking and keeping reconstituted material refrigerated are standard peptide handling practice.

  
## Practical Considerations

* **Time to effect:** In rodents, behavioural change appeared after a single dose and consolidated over four days ([Djillani et al., 2017](https://pubmed.ncbi.nlm.nih.gov/28955242/)). No human timeline exists; the four-day figure is the fastest claim in the literature and has never been tested in people.

* **Common pitfall — treating potency as clinical strength:** The 0.12 nanomolar figure describes channel binding in a dish, not human effect. Mistaking it for evidence of a strong antidepressant effect is the most frequent error in material promoting this peptide.

* **Common pitfall — converting rodent doses:** The validated animal dose is micrograms per kilogram; amounts reported in practice are milligram totals, hundreds of times higher per kilogram. No published method bridges the two.

* **Common pitfall — assuming a clean safety profile:** "No adverse effects reported" reflects the absence of human exposure records, not reassurance, and the original claim came from the patent-holding laboratory's own animal work.

* **Regulatory status:** Not approved for any indication and not eligible for pharmacy compounding ([FDA](https://www.fda.gov/drugs/human-drug-compounding/bulk-drug-substances-used-compounding-under-section-503a-fdc-act)). The World Anti-Doping Agency's Prohibited List bans non-approved substances in category S0 at all times ([WADA](https://www.wada-ama.org/en/prohibited-list)), so competing athletes are affected.

* **Cost and accessibility:** Accessible only through online research-chemical vendors or private clinics, at prices far above generic antidepressants. Payers and health systems have a structural incentive to favour cheap generics, which also shapes which comparators get funded and studied.

  
## Interaction with Foundational Habits

* **Sleep:** Direction uncertain, plausibly stimulating. Blocking a channel whose job is to keep neurons quiet raises excitability, and the channel is widely expressed in brain ([Djillani et al., 2019](https://pubmed.ncbi.nlm.nih.gov/31031627/)). No sleep measurement has been published for the peptide. Practical consequence: morning rather than evening dosing, and tracking sleep onset through the first weeks.

* **Nutrition:** Direct and blunting in both directions. Polyunsaturated fatty acids from fish oil and flaxseed are the channel's natural openers ([Lauritzen et al., 2000](https://pubmed.ncbi.nlm.nih.gov/10775263/)), so a high intake works against the peptide while the peptide works against them. Separating supplements from dosing by several hours is the practical step.

* **Exercise:** Indirect, through glucose. The parent peptide amplified insulin release in cells and mice ([Hivelin et al., 2016](https://pubmed.ncbi.nlm.nih.gov/28105440/)), so long fasted endurance sessions are where low blood sugar would most plausibly surface. Nothing suggests an effect on strength adaptation or muscle growth; no exercise study exists.

* **Stress management:** Indirect and potentially potentiating. Channel-deleted mice showed a substantially smaller rise in corticosterone ([Heurteaux et al., 2006](https://pubmed.ncbi.nlm.nih.gov/16906152/)), and the peptide still worked in animals under prolonged corticosterone exposure. Practical consequence: stress-reduction practices address the same axis the peptide is proposed to act on.

  
## Monitoring Protocol & Defining Success

No validated monitoring protocol exists for PE-22-28, because no human study has measured any outcome. The tests below are safety checks derived from what blocking TREK-1 does in animal and cell work: the channel sits in pancreatic beta cells, heart pacemaker tissue and the drainage tissue of the eye, so glucose handling, cardiac rhythm and eye pressure are the plausible places for an unwanted effect to show. Baseline testing means recording all four before any exposure, so that any later change can be compared with the person's own starting values rather than a population range. Ongoing testing follows the same panel at four weeks, then every three to six months while exposure continues, with fasting glucose and insulin repeated sooner if symptoms of low blood sugar appear. None of these intervals comes from a trial; they reflect common practice for an unstudied compound.

| Biomarker | Optimal Functional Range | Why Measure It? | Context/Notes |
|---|---|---|---|
| Fasting plasma glucose | 70–99 mg/dL (standard reference range) | Safety check: a fall below range stops or reduces use, given increased insulin release in animals | Requires 8–12 hours fasting; draw in the morning and pair with fasting insulin in the same sample |
| Fasting insulin | 2.6–24.9 µIU/mL (standard reference range) | Safety check: a rise above range alongside falling glucose signals the animal insulin-release effect occurring in a person | Same fasted draw as glucose; results are assay-specific, so repeat testing should use the same laboratory |
| Resting 12-lead electrocardiogram | No established target — track heart rate and rhythm against the individual's own pre-exposure recording | Safety check: a new slow rate, pause or conduction change stops use, given bradycardia in heart-specific channel-deleted mice | Record before caffeine or exercise; keep the baseline tracing for direct comparison rather than relying on a report |
| Intraocular pressure | 10–21 mmHg (standard reference range) | Safety check: a rise above range stops use, given the channel's role in the eye's pressure-regulating drainage tissue | Measure at a consistent time of day, as pressure varies through the day; most relevant where glaucoma is present |

Qualitative markers to track alongside the tests above:

* Mood, assessed by repeating the same standard depression rating scale at the same time of week rather than switching instruments
* Sleep onset latency and night-time waking, given the channel's role in neuronal excitability
* Energy and motivation during the first two weeks, when any rapid-onset effect would be expected
* Cognitive clarity and short-term memory, the domains most affected when mood shifts
* Episodes of sweating, tremor, hunger or confusion between meals, which would point to low blood sugar
* New visual symptoms, eye ache or haloes around lights, which would point to raised eye pressure

  
## Emerging Research

* **No registered trial of the peptide:** A ClinicalTrials.gov search for PE-22-28, mini-spadin, spadin and TREK-1 returns no interventional study of any of these peptides. A positive first-in-human safety study would move every item in this review off Speculative; a halted one would close the question.

* **Anti-TREK-1 autoantibodies in short-coupled ventricular fibrillation:** [NCT06943365](https://clinicaltrials.gov/study/NCT06943365), studying a rhythm disorder that causes unexplained cardiac arrest, is recruiting 300 participants for repeat plasma screening, completion expected December 2028. A positive finding would make immune interference with this channel a named human risk; a null result would weaken that concern.

* **STROKDEM, completed 2021 with results published:** [NCT01330160](https://clinicaltrials.gov/study/NCT01330160) followed 229 stroke patients observationally. Serum sortilin propeptide levels tracked depression scores but not anxiety scores ([Mazella et al., 2025](https://pubmed.ncbi.nlm.nih.gov/40107034/)) — human biomarker support for the target, not for the peptide.

* **Whether the peptide blocks the channel at all:** The independent finding that spadin only prevents fatty-acid activation ([Ma & Lewis, 2020](https://pubmed.ncbi.nlm.nih.gov/32317978/)) could weaken the whole rationale if extended to PE-22-28, or sharpen the dosing model if the indirect binding site is mapped.

* **Dose direction in brain injury:** Mini-spadin activated the channel at low doses and blocked it at high ones ([Pietri et al., 2019](https://pubmed.ncbi.nlm.nih.gov/31325429/)). Replication by an independent group would make dose direction central to the protocol; failure would remove the stroke claim.

* **Cardiac consequences of losing channel function:** Heart-specific channel deletion worsened remodelling and prolonged electrical intervals after pressure overload ([Johnson et al., 2025](https://pubmed.ncbi.nlm.nih.gov/40387641/)). Confirmation with a pharmacological blocker would raise the cardiac risk grade; a null result would ease it.

* **Metabolic direction of channel blockade:** Opposing signals exist — better beta-cell survival ([Daziano et al., 2021](https://pubmed.ncbi.nlm.nih.gov/33737242/)) against more fat gain and worse glucose tolerance ([Kim et al., 2025](https://pubmed.ncbi.nlm.nih.gov/40057491/)). Resolution would determine whether metabolic effects belong among benefits or risks.

* **Patent timeline shaping development:** The granted patent runs to 2037 ([US11220527B2](https://patents.google.com/patent/US11220527B2/en)). Licensing to a developer would bring trial data; expiry without a trial would leave the peptide permanently in unregulated supply, where its risks are hardest to measure.

  
## Conclusion

PE-22-28 is a seven-amino-acid laboratory peptide built from a fragment of a natural human peptide, designed to block a single potassium channel that normally keeps nerve cells quiet. It binds that channel tightly and leaves close relatives alone.

Everything claimed for it rests on mice, rats and cultured cells: faster mood-related behavioural change than standard medicines, more new brain cells and more connections between them, better recovery after induced stroke, and protection of insulin-producing cells. None has been measured in a person. The same gap runs through the risks. Deleting the channel in animals raises seizure and pain sensitivity, worsens brain injury, slows the heart, shifts fat storage and glucose handling, and eases immune cells into the brain, while the peptide itself did not reproduce several of these in the animals tested. Which reading holds in people is unknown.

The evidence base is narrow in a way that matters. Almost all of it comes from the single laboratory that discovered these peptides and whose institutions hold the patent covering them, a direct financial interest in their adoption; the consumer pages describing how the peptide is used sit on commercial health sites. No professional body has taken a position either way, so nothing here reflects a settled view. Cheap established alternatives also mean insurers and health systems have no financial stake in comparing them with a patented peptide. Supply is unregulated, and testing of comparable products sold the same way found most of the labelled content absent.

**[Top](#top) - [Benefits](#expected-benefits) - [Risks](#potential-risks--side-effects) - [Protocol](#therapeutic-protocol)**