PE 22-28, mini-spadin, shortened spadin analog
A seven-amino-acid piece of spadin, the fragment released when the protein sortilin is processed. It blocks the TREK-1 potassium channel and produced antidepressant-like behavior in mice within about 4 days; with spadin itself, blocking TREK-1 made serotonin neurons fire faster.
Category 2 is FDA’s list of bulk substances that may present significant safety risks in compounding. The 503A bulks list adds substances that pharmacies may compound with. Advisory committee votes are advice; FDA makes the final decision. Sport status follows the WADA Prohibited List in force since January 1, 2026; athletes should confirm with their anti-doping organization. Checked October 5, 2026. Status of every compound.
PE-22-28 blocks TREK-1, a potassium channel that acts as a brake on nerve cells; in cells carrying the human channel it did so at far lower concentrations than spadin, its parent peptide. In mice it reduced depression-like behavior and boosted new nerve cell growth in the hippocampus, a memory area, within 4 days. In spadin’s mouse studies, blocking TREK-1 made serotonin nerve cells fire faster.
AnimalMainly from cell and animal studies; not shown in people.
No study has given it to a person, so it isn’t known whether it reaches the human brain after injection or nasal spray, what amount would matter, or what long-term TREK-1 blockade does.
50–600 mcg once daily, by injection under the skin or as a nasal spray. Guides disagree widely: some put the usual amount at 50–200 mcg, others at 250–400 mcg. No human dose has been tested.
No set cycle, shown over 26 weeks
The ways PE-22-28 is most often run, each tagged with where it comes from.
The most described route. The two dose bands don’t overlap, and neither comes from a human study.
Used by people who would rather not inject, and to match Selank and Semax nasal routines. How much is absorbed in people is unknown.
Listed because every community figure is scaled from it. These are animal doses and say nothing about a safe or useful human amount.
Community use is an injection under the skin of the belly or thigh, rotating sites, or a nasal spray. The published work injected mice into the abdomen or gave the peptide by stomach tube.
No published guidance. Skip the missed dose and resume the next day; don’t double up.
The claimed selling point is speed: in mice, behavior changed after 4 days of once-daily dosing, against 3–4 weeks for an SSRI. No equivalent has been measured in people.
CommunityUsers describe lifted mood or drive, and some describe nothing. There is no trial to compare against.
CommunityGuides stop here and take a break, because no data of any kind cover longer use.
CommunityNo human side effect profile exists
There is no Phase 1 study, so the list below is only what users report. Absence of reports is not evidence of safety.
Restlessness, anxiety or lighter sleep
Reported at the higher amounts and with evening doses. Lower the amount or dose earlier.
Nasal burning or dryness (nasal route)
Split the dose between nostrils, or stop.
Injection-site redness or soreness
Rotate sites and use sterile technique. Spreading redness, heat or pus needs medical care.
Allergic reaction, possible with any injected peptide
Stop and get emergency care for hives, facial swelling or trouble breathing.
Stop and get medical help for hives, swelling of the face or throat, trouble breathing, a seizure, chest pain or palpitations, or a hot, spreading injection site with fever. Thoughts of self-harm need urgent medical help, not a change of peptide.
No product label covers PE-22-28, so these come from human studies and from precautions based on how it works. Most important first.
Precaution: follows from how it works or from a related drug, and hasn’t been tested. This isn’t a complete list: a pharmacist or doctor can check a specific medicine or condition.
No published human studies of PE-22-28 turned up in our October 2026 review. The evidence note at the top of this page sums up what is known.
PE-22-28 has never been given to a person. Its evidence is a handful of mouse and cell studies, almost all from one French laboratory, using doses per kilogram injected into the abdomen or given by stomach tube. Human absorption, dosing, side effects, interactions and long-term safety are untested, and research vials have no regulated standard for purity.
| Vial | Water | Common dose | Draw | Strength | Action |
|---|---|---|---|---|---|
| 5 mg | 2 mL | – | – | 2.5 mg/mL | |
| 10 mg | 3 mL | – | – | 3.333 mg/mL |
Bacteriostatic water. A 10 mg vial in 3 mL gives about 3.3 mg/mL, which makes amounts under 100 mcg hard to measure even on a 0.3 mL syringe; guides that use 50–100 mcg usually mix more thinly.
Every compound side by side: the half-life chart and the storage chart.
A seven-amino-acid piece of spadin, the fragment released when the protein sortilin is processed. It blocks the TREK-1 potassium channel and produced antidepressant-like behavior in mice within about 4 days; with spadin itself, blocking TREK-1 made serotonin neurons fire faster.
PE-22-28 blocks TREK-1, a potassium channel that acts as a brake on nerve cells; in cells carrying the human channel it did so at far lower concentrations than spadin, its parent peptide. In mice it reduced depression-like behavior and boosted new nerve cell growth in the hippocampus, a memory area, within 4 days. In spadin’s mouse studies, blocking TREK-1 made serotonin nerve cells fire faster. No study has given it to a person, so it isn’t known whether it reaches the human brain after injection or nasal spray, what amount would matter, or what long-term TREK-1 blockade does.
Not approved as a drug anywhere, and never studied in people. No investigational application for PE-22-28 or spadin appears on the public record, and neither is registered on ClinicalTrials.gov. Not nominated for either of FDA’s compounding bulk-substance lists, so it appears in no category, Category 1 or Category 2, for 503A or 503B.
From community reports, not established: 50–600 mcg once daily, by injection under the skin or as a nasal spray. Guides disagree widely: some put the usual amount at 50–200 mcg, others at 250–400 mcg. No human dose has been tested. These are the amounts sources reference, not recommendations.
No product label covers PE-22-28, so these come from human studies and from precautions based on how it works. Epilepsy or a history of seizures: Mice lacking TREK-1 have seizures more easily. Spadin, its parent peptide, didn’t change seizures in mice, but no human study exists. Anyone taking antidepressants or other serotonin drugs: Blocking TREK-1 made serotonin nerve cells fire faster in mice. Combining it with antidepressants, triptans (migraine drugs) or MAO inhibitors has never been tested. Heart rhythm problems: TREK-1 is also found in the heart. Spadin didn’t change heart function, heart rate or blood pressure in mice, but no study has checked this in people. The “Who should avoid it” section lists 2 more groups.
Before mixing: Freezer (about −20 °C) for long-term storage, dry and away from light. After mixing: Fridge (2–8 °C); use within about 4 weeks. This is common practice; no product label covers it.
Probably. Not named on the 2026 list, and potassium-channel blockers are not a listed class. S0 applies: no governmental health authority anywhere approves a medicine containing it, so it is banned at all times.
No published human studies turned up in our October 2026 review. The evidence note at the top of this page sums up what is known.
For how it works, who should avoid it and the limits of the evidence
Doses tagged Community come from public dosing guides and user reports, checked against at least two of them. Those sites aren’t named here because many of them sell peptides or earn commissions on them.