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Specimen Atlas of Research Peptides81 plates · MIT
Side-by-side · Research reference

MazdutidevsPE 22-28

Side-by-side comparison across mechanism, dosage, evidence, side effects, administration, and stack synergies. Citations on every claim where available.

APhase 3HUMAN-REVIEWED19/62 cited
BAnimal-StrongHUMAN-REVIEWED16/47 cited
Mazdutide
GLP-1/Glucagon Dual Agonist · Oxyntomodulin Analogue · Phase 3
9 mgWeekly doseJi 2026
12.4%Weight lossAzam 2026
Phase 3Status (China)
SQ · Abdomen · Once WeeklyJi 2026
PE 22-28
TREK-1 Antagonist · Pre-Clinical
0.12 nMTREK-1 IC50Djillani 2017
7 AAPeptide lengthDjillani 2017
AnimalEvidence stage
IP · SQ · Once Daily (animal models)Djillani 2017Pietri 2019

01Mechanism of Action

Parameter
Mazdutide
PE 22-28
Primary target
GLP-1 receptor and glucagon receptorAbdul 2026Elmendorf 2026
TREK-1 two-pore-domain potassium channelDjillani 2017Ma 2020
Pathway
Dual agonism: GLP-1R → satiety, insulin secretion, gastric emptying delay; GCGR → hepatic lipolysis, energy expenditure, thermogenesisElmendorf 2026Abulehia 2026
TREK-1 channel blockade → Neuronal membrane depolarisation → Enhanced hippocampal excitability → Increased neuroplasticity
Downstream effect
Weight loss via appetite suppression (GLP-1 axis) and increased energy expenditure (glucagon axis); improved glycemic control in T2D
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
Feedback intact?
Yes — physiological receptor-mediated signaling preserved
N/A — direct ion channel blockade; not receptor-mediated endocrine axis
Origin
Synthetic oxyntomodulin analogue — endogenous peptide with dual GLP-1/glucagon activity
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
Antibody development
Not reported in animal studies

02Dosage Protocols

Parameter
Mazdutide
PE 22-28
Phase 2 studied dose
9 mg / weekJi 2026
Highest efficacy dose in obesity trial (BMI ≥30 kg/m²).Ji 2026
Frequency
Once weeklyJi 2026Luo 2026
Once daily
Sustained antidepressant effect over 7+ days.
Route
SubcutaneousJi 2026
Dose escalation
3 mg → 6 mg → 9 mg (titration schedule in trials)
Gradual escalation to minimize GI side effects.
Evidence basis
Phase 2 RCT / Phase 3 ongoingJi 2026Luo 2026
Multiple rodent RCTs; behavioral + electrophysiology endpointsDjillani 2017Qi 2018Wu 2021
Duration (trials)
24–48 weeks
Population
Non-diabetic adults BMI ≥30 kg/m² or ≥27 kg/m² with comorbidities
Phase 3 comparator
Semaglutide 1 mg/week (DREAMS-3 trial)Luo 2026
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.
Onset (animal)
Within hours (acute); full effect 4–7 days
Duration (animal)
7–28 days testedQi 2018Pietri 2019
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.

03Metabolic / Fat Loss Evidence

Parameter
Mazdutide
PE 22-28
Percentage body weight loss
12.4% (pooled meta-analysis, 9 mg dose)
95% CI: -16.15% to -8.68%, random-effects model.Azam 2026
Absolute weight loss
9.8 kg (mean)Azam 2026
95% CI: -13.15 to -6.37 kg.Azam 2026
Responder rate (≥10% loss)
Not explicitly reported in available abstracts
Mechanism
Appetite suppression (GLP-1) + energy expenditure (glucagon)Elmendorf 2026
BMI reduction
Significant reduction in Chinese adults BMI ≥30 kg/m²Ji 2026
Visceral fat
Expected benefit from glucagon-mediated lipolysis (not quantified in abstracts)
Glycemic improvement
HbA1c reduction in T2D cohort (Phase 3 DREAMS-3)
Comparator efficacy
Head-to-head vs semaglutide 1 mg (Phase 3 pending publication)Luo 2026
Key publications
Ji et al. Med 2026 · Azam et al. Diab Obes Metab 2026 · Luo et al. Contemp Clin Trials 2026

04Side Effects & Safety

Parameter
Mazdutide
PE 22-28
Gastrointestinal symptoms
Nausea, vomiting, diarrhea (most common, GLP-1 effect)
Injection site reactions
Erythema, pruritus, local discomfort
Hypoglycemia
Low risk in non-diabetic cohort; monitor in T2D with insulin or sulfonylureas
Cardiovascular effects
Increased heart rate (glucagon effect, transient)
Pancreatitis risk
Theoretical (incretin class effect); monitor amylase/lipase if abdominal pain
Thyroid C-cell tumors
Black box warning for GLP-1 class (rodent data); human relevance unclear
Gallbladder disease
Cholelithiasis, cholecystitis (rapid weight loss effect)
Tolerability
Generally well-tolerated; GI effects diminish with dose titration
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
Absolute Contraindications
Mazdutide
  • ·Personal or family history of medullary thyroid carcinoma
  • ·Multiple endocrine neoplasia syndrome type 2 (MEN 2)
  • ·Hypersensitivity to mazdutide or excipients
  • ·Pregnancy
PE 22-28
  • ·Human use — no clinical safety data available
Relative Contraindications
Mazdutide
  • ·History of pancreatitis
  • ·Severe gastroparesis or GI motility disorders
  • ·Diabetic retinopathy (monitor, risk of worsening with rapid glycemic change)
  • ·Renal impairment (limited data, use with caution)
PE 22-28
  • ·Cardiac arrhythmia or channelopathy (theoretical TREK-1 cardiac role)

05Administration Protocol

Parameter
Mazdutide
PE 22-28
1. Preparation
Supplied as pre-filled pen or reconstituted vial (per manufacturer instructions). Inspect solution — should be clear, colorless to pale yellow. Discard if cloudy or particulate matter present.
Dissolved in sterile saline or vehicle. Intraperitoneal injection, 0.3–3 µg/kg body weight. Once daily administration in rodent behavioral studies.
2. Injection site
Subcutaneous — abdomen preferred, also thigh or upper arm. Rotate sites weekly. Avoid areas with scarring, moles, or active inflammation.
Shorter peptide length (7 AA) confers improved plasma stability vs 17-AA spadin. Exact storage conditions not detailed in published protocols.Djillani 2017
3. Timing
Once weekly, same day each week. May be taken with or without food. If dose missed, administer within 3 days; if >3 days, skip and resume next scheduled dose.
Enhanced CNS bioavailability vs full spadin, likely due to smaller size. Mechanism (passive diffusion vs active transport) not fully characterized.
4. Storage
Refrigerate 2–8 °C. Do not freeze. May be kept at room temperature (<25 °C) for up to 14 days if needed. Protect from light.
Not established — peptide synthesis methods for research use only. No pharmaceutical-grade formulation available.
5. Needle technique
Use supplied needle or compatible insulin syringe (if reconstituting). Pinch skin, inject at 90° angle. Hold 5–10 seconds before withdrawing needle to prevent leakage.