Side-by-side · Research reference
GLP-1 (7-37)vsP21
Side-by-side comparison across mechanism, dosage, evidence, side effects, administration, and stack synergies. Citations on every claim where available.
AHuman-MechanisticHUMAN-REVIEWED16/43 cited
BAnimal-MechanisticHUMAN-REVIEWED8/36 cited
GLP-1 (7-37)
Incretin Hormone · Native Peptide
Research use only · IV/SC in experimental settings
P21
CNTF-Derived Neuropeptide · Animal Model Evidence
Animal onlyEvidence level
SQ · Site unspecified · Frequency unknown
01Mechanism of Action
Parameter
GLP-1 (7-37)
P21
Primary target
GLP-1 receptor (class B GPCR)Koole 2015
CNTF receptor alpha (CNTFRα) / LIF receptor (LIFR) / gp130 complex on neural stem cells
Pathway
GLP-1R activation → cAMP production → PKA signaling → insulin secretion (pancreatic β-cells)Lu 2025Koole 2015
CNTF mimetic → CNTFRα/LIFR/gp130 heterotrimer → JAK/STAT3 signaling → neurogenesis, stem cell proliferation, neuroprotection
Downstream effect
Glucose-dependent insulin release, glucagon suppression, delayed gastric emptying, reduced food intakeLu 2025Ding 2017
Increased neural stem cell self-renewal, globose basal cell activation (Mash1+ cells), olfactory sensory neuron regeneration, hippocampal neurogenesis, neuroprotection in developmental disorders
Feedback intact?
Yes — physiological secretion and degradation preserved
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Origin
Endogenous peptide cleaved from proglucagon in intestinal L cells; secreted postprandially
Small-molecule peptide mimetic derived from full-length ciliary neurotrophic factor (CNTF), designed to retain receptor activation with improved pharmacokineticsMottolese 2024
Antibody development
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02Dosage Protocols
Parameter
GLP-1 (7-37)
P21
Clinical use
None — native GLP-1 not used therapeutically
Engineered analogues (semaglutide, liraglutide) used clinically.Friedman 2024
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Research dosing
Variable — 0.1–10 nmol/kg in animal models
Used as reference standard for analogue comparison.
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Modified analogues
t½ extended to 13 h (liraglutide), 165 h (semaglutide)
Via DPP-4 resistance + fatty acid acylation.
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Human dosing
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No established protocol
No clinical trial data available.
Animal models (mice)
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Dose and route not specified in abstractsMottolese 2024Jia 2020
In vitro and in vivo studies demonstrate efficacy; precise dosing protocols not disclosed.
Evidence basis
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Animal models only
CDKL5 KO mice, methimazole-induced olfactory injury, CNTF-/- knockout models.Mottolese 2024Cox 2026Jia 2020
Duration
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Not specified
Route
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Presumed subcutaneous or intraperitoneal (animal studies)
03Metabolic / Fat Loss Evidence
Parameter
GLP-1 (7-37)
P21
Mechanism
GLP-1R activation in hypothalamic satiety centers (arcuate nucleus) reduces food intakeLu 2025
Effect demonstrated with long-acting analogues (liraglutide).Lu 2025
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Native GLP-1 efficacy
Minimal — rapid degradation prevents sustained appetite suppression
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Gastric emptying
Delayed in animal models, contributing to satiety
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Body weight impact
Not observed with native GLP-1 — requires analogue formulations
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04Side Effects & Safety
Parameter
GLP-1 (7-37)
P21
Native GLP-1
Well-tolerated in research settings; no prolonged exposure data
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Hypoglycemia risk
Low — insulin secretion is glucose-dependent
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Analogue side effects
Nausea, vomiting, diarrhea (GLP-1R agonists)
Not applicable to native GLP-1 due to non-therapeutic use.
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GLP-1 resistance
High glucose-induced PKCβ overexpression may reduce GLP-1 responsiveness in endothelial cellsPujadas 2016
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Human safety data
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None available
No clinical trials in humans.
Animal tolerability
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Well-tolerated in mouse models; no toxicity reported in available abstracts
Theoretical risks
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Uncontrolled stem cell proliferation, immune response to peptide, unknown long-term CNS effects
Absolute Contraindications
GLP-1 (7-37)
—P21
- ·Use in humans not validated
Relative Contraindications
GLP-1 (7-37)
—P21
- ·Active malignancy (theoretical — neurotrophic signaling may affect tumour growth)
- ·Pregnancy or lactation (no safety data)
05Administration Protocol
Parameter
GLP-1 (7-37)
P21
1. Research use only
Native GLP-1(7-37) is not formulated for therapeutic use. Administered IV or SC in experimental protocols to study GLP-1R pharmacology and as reference standard for analogue development.
Not established. No FDA approval, no clinical trial data.
2. Storage
Lyophilised peptide stored at -20°C or below. Reconstituted solutions should be prepared fresh and used immediately due to rapid degradation.
In vivo studies used systemic administration (route not specified in abstracts) in mouse models of neurodegeneration, olfactory injury, and CDKL5 deficiency disorder. In vitro studies used primary cell cultures.
3. Clinical alternatives
For therapeutic GLP-1R activation, use FDA-approved long-acting analogues: semaglutide (once weekly), liraglutide (once daily), dulaglutide (once weekly), or exenatide (twice daily or once weekly).
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