Side-by-side · Research reference
PE 22-28vsThymosin α-1
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
BPhase 3HUMAN-REVIEWED8/39 cited
PE 22-28
TREK-1 Antagonist · Pre-Clinical
IP · SQ · Once Daily (animal models)Djillani 2017Pietri 2019
Thymosin α-1
Immune modulator · Approved (some countries)
SQ · 2× weekly · 6+ months for chronic indications
01Mechanism of Action
Parameter
PE 22-28
Thymosin α-1
Primary target
TREK-1 two-pore-domain potassium channelDjillani 2017Ma 2020
Toll-like receptor 9 (TLR9) + T-cell maturation pathwayCamerini 2001
Pathway
TREK-1 channel blockade → Neuronal membrane depolarisation → Enhanced hippocampal excitability → Increased neuroplasticity
TLR9 activation → ↑ IFN-α + IL-2 + IFN-γ → enhanced T-cell function + dendritic cell maturationIyer 2007
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
Restored T-cell function, improved viral clearance, anti-tumour adjuvant effectsIyer 2007
Feedback intact?
N/A — direct ion channel blockade; not receptor-mediated endocrine axis
—
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
Synthetic 28-AA peptide identical to natural Tα-1 isolated from thymus extractCamerini 2001
Antibody development
Not reported in animal studies
—
02Dosage Protocols
Parameter
PE 22-28
Thymosin α-1
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.
2× weekly (Mon/Thu typical)
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
Phase 3 + approved (35+ countries as Zadaxin)Iyer 2007
Lower / starter dose
—
0.8 mg per injection
Duration
—
6–12 months for chronic indications
Reconstitution
—
Sterile water for injection per vial label
Timing
—
No specific time
Half-life
—
~2 hours plasma; tissue effect days
04Side Effects & Safety
Parameter
PE 22-28
Thymosin α-1
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
—
Erythema, mild discomfort
GI symptoms
—
Rare nausea
Fatigue
—
Common during initial weeks
Fever / flu-like
—
Mild interferon-like response possible
Autoimmune
—
Theoretical risk; caution in active autoimmune disease
Cancer risk
—
No signal — used as adjuvant in oncology
Pregnancy / OB
—
Avoid
Absolute Contraindications
PE 22-28
- ·Human use — no clinical safety data available
Thymosin α-1
- ·Pregnancy / breastfeeding
- ·Hypersensitivity to peptide
- ·Concurrent immunosuppressant therapy (transplant patients)
Relative Contraindications
PE 22-28
- ·Cardiac arrhythmia or channelopathy (theoretical TREK-1 cardiac role)
Thymosin α-1
- ·Active autoimmune disease
- ·Severe immunocompromised state without supervision
05Administration Protocol
Parameter
PE 22-28
Thymosin α-1
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.
Add 1 mL sterile water per 1.6 mg vial → 1.6 mg/mL.
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.
3. BBB penetration
Enhanced CNS bioavailability vs full spadin, likely due to smaller size. Mechanism (passive diffusion vs active transport) not fully characterized.
2× weekly, e.g. Monday + Thursday.
4. Human formulation
Not established — peptide synthesis methods for research use only. No pharmaceutical-grade formulation available.
Lyophilised: refrigerate. Reconstituted: refrigerate, use within 24 h.
5. Needle
—
27–31G, 4–8 mm insulin syringe.