Side-by-side · Research reference
PE 22-28vsSemaglutide
Side-by-side comparison across mechanism, dosage, evidence, side effects, administration, and stack synergies. Citations on every claim where available.
AAnimal-StrongHUMAN-REVIEWED16/47 cited
BFDA-ApprovedFlagship15/53 cited
PE 22-28
TREK-1 Antagonist · Pre-Clinical
IP · SQ · Once Daily (animal models)Djillani 2017Pietri 2019
Semaglutide
GLP-1 RA · FDA-Approved
SQ · Abdomen / thigh / arm · Once weekly
01Mechanism of Action
Parameter
PE 22-28
Semaglutide
Primary target
TREK-1 two-pore-domain potassium channelDjillani 2017Ma 2020
GLP-1 receptor (GLP-1R)WEGOVY (semaglutide) injection 2021
Pathway
TREK-1 channel blockade → Neuronal membrane depolarisation → Enhanced hippocampal excitability → Increased neuroplasticity
GLP-1R agonism → ↑glucose-dependent insulin secretion, ↓glucagon, ↓gastric emptying, ↓appetite via hypothalamic centresWilding 2021
Downstream effect
Antidepressant-like activity in forced swim test and tail suspension test; reduced A1-like reactive astrocyte activation; neuroprotection via NF-κB pathway modulationDjillani 2017Cong 2023Wu 2021
Improved glycemic control, reduced caloric intake, body-weight reduction, cardiovascular risk reductionWilding 2021
Feedback intact?
N/A — direct ion channel blockade; not receptor-mediated endocrine axis
Glucose-dependent insulin release preserves physiological feedback
Origin
Synthetic truncation of spadin (PE 12-28), itself derived from the sortilin propeptide C-terminus. Residues 22-28: Val-Val-Arg-Gly-Trp-Leu-Arg.Djillani 2017Mazella 2018
Modified GLP-1(7-37) with two amino-acid substitutions and C-18 fatty-acid acylation for albumin binding and 168-h half-lifeWEGOVY (semaglutide) injection 2021
Antibody development
Not reported in animal studies
—
02Dosage Protocols
Parameter
PE 22-28
Semaglutide
Animal dose (antidepressant)
0.3–3 µg/kg IP
Effective in forced swim test, tail suspension test, CUMS models.
—
Animal dose (neuroprotection)
0.03 µg/kg IPPietri 2019
Low-dose TREK-1 activation post-stroke for 7 days, then high-dose blockade.
—
Frequency
Once daily
Sustained antidepressant effect over 7+ days.
Once weekly, same day each week
Onset (animal)
Within hours (acute); full effect 4–7 days
—
Comparison to fluoxetine
PE 22-28 outperforms fluoxetine in CUMS-sensitive rats by day 7
Chronic administration shows superior long-term efficacy.
—
Human equivalent (extrapolated)
Not established — no clinical trials
Allometric scaling from rodent data unavailable.
—
Evidence basis
Multiple rodent RCTs; behavioral + electrophysiology endpointsDjillani 2017Qi 2018Wu 2021
FDA-approved · Phase 3 RCTsWilding 2021WEGOVY (semaglutide) injection 2021
Standard dose (weight, Wegovy)
—
2.4 mg / week (after 16-wk titration)WEGOVY (semaglutide) injection 2021Wilding 2021
Titration schedule
—
0.25 → 0.5 → 1.0 → 1.7 → 2.4 mg over 16 weeks
Mitigates GI side effects.
Duration
—
Indefinite for chronic indication
Discontinuation results in weight regain.
Reconstitution
—
Pre-mixed pen device (commercial). Research lyophilised vial: bacteriostatic water per label.
Timing
—
Any time of day, with or without food
04Side Effects & Safety
Parameter
PE 22-28
Semaglutide
Toxicity (animal)
No adverse effects reported at therapeutic doses
—
Cardiovascular (theoretical)
TREK-1 expressed in cardiac tissue; arrhythmia risk unclear
—
Weight change
Not reported in animal studies
—
Neurological
No seizures or behavioral abnormalities noted
—
Long-term safety
Unknown — longest animal study 28 days
—
Injection site reaction
—
Mild erythema, pruritus
Thyroid C-cell tumours
—
Boxed warning — contraindicated in MEN2 / personal or family MTC historyWEGOVY (semaglutide) injection 2021
Hypoglycemia
—
Low risk as monotherapy; elevated when combined with sulfonylureas / insulin
Gallbladder events
—
Increased cholelithiasis
Heart rate
—
Modest ↑ resting HR (~2-4 bpm)
Absolute Contraindications
PE 22-28
- ·Human use — no clinical safety data available
Semaglutide
- ·Personal or family history of medullary thyroid carcinoma
- ·Multiple endocrine neoplasia syndrome type 2
- ·Pregnancy / breastfeeding
- ·Hypersensitivity to semaglutide
Relative Contraindications
PE 22-28
- ·Cardiac arrhythmia or channelopathy (theoretical TREK-1 cardiac role)
Semaglutide
- ·Severe gastroparesis
- ·History of pancreatitis
- ·Diabetic retinopathy (may worsen with rapid glycemic improvement)
05Administration Protocol
Parameter
PE 22-28
Semaglutide
1. Animal protocol (IP)
Dissolved in sterile saline or vehicle. Intraperitoneal injection, 0.3–3 µg/kg body weight. Once daily administration in rodent behavioral studies.
Commercial: pre-filled pen, no reconstitution. Research vial: per-label or bacteriostatic water.
2. Stability
Shorter peptide length (7 AA) confers improved plasma stability vs 17-AA spadin. Exact storage conditions not detailed in published protocols.Djillani 2017
SQ — abdomen, thigh, or upper arm. Rotate sites weekly to avoid lipohypertrophy.
3. BBB penetration
Enhanced CNS bioavailability vs full spadin, likely due to smaller size. Mechanism (passive diffusion vs active transport) not fully characterized.
Once weekly, same day. Day can be changed if ≥2 days separate doses.
4. Human formulation
Not established — peptide synthesis methods for research use only. No pharmaceutical-grade formulation available.
Pen: refrigerate 2–8 °C unopened; room temp ≤30 °C up to 56 days after first use.
5. Needle
—
Pen-supplied 31–34G needle. Research vial: 27–31G insulin syringe.
06Stack Synergy
PE 22-28
— no documented stacks
Semaglutide
+ Tirzepatide
WeakCombining two GLP-1 RA-class drugs is not clinically validated and risks additive GI toxicity. Tirzepatide's GIP component already provides complementary mechanism vs pure GLP-1; stacking with semaglutide adds receptor saturation but no synergy. NOT recommended.
- Note
- Stack not recommended — choose one GLP-1 RA
- Primary benefit
- (none — additive toxicity, no synergy)