Side-by-side · Research reference
HGH Fragment 176-191vsLL-37
Side-by-side comparison across mechanism, dosage, evidence, side effects, administration, and stack synergies. Citations on every claim where available.
AAnimal-StrongHUMAN-REVIEWED28/59 cited
BHuman-MechanisticHUMAN-REVIEWED15/35 cited
HGH Fragment 176-191
GH Fragment · Pre-Clinical
SQ · IP (animal) · Oral (tested)
LL-37
Cathelicidin · Human AMP
Broad-spectrumAntimicrobial activity
Endogenous · Secreted at inflammation sites
01Mechanism of Action
Parameter
HGH Fragment 176-191
LL-37
Primary target
Beta-3 adrenergic receptors on adipocytesHeffernan 2001
Pathway
Fragment → β3-AR upregulation → Enhanced lipolytic sensitivityHeffernan 2001
hCAP-18 precursor → Proteinase-3 cleavage → LL-37 release → Membrane insertion/disruption
Downstream effect
Increased lipolysis and beta-3 AR mRNA expression without IGF-1 axis activation
Membrane permeabilization, cytokine induction, autophagy, phagosome-lysosome fusion, chemotaxisAhmad 2026Zhang 2026
Feedback intact?
N/A — does not interact with GH/IGF-1 axis
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Origin
Synthetic peptide derived from hGH residues 176-191; AOD9604 includes N-terminal tyrosine (177-191)Cox 2015
Endogenous human cathelicidin (37-AA fragment, residues 134–170 of hCAP-18)
Antibody development
Not reported in available studies
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02Dosage Protocols
Parameter
HGH Fragment 176-191
LL-37
Animal dose (IP)
Not specified (14-day chronic administration)Heffernan 2001
Obese mice, daily IP injection.
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Human equivalent dose
Not established — no published human RCTs
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Frequency
Once daily (animal models)
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Evidence basis
Animal studies only
In vitro, animal models, human observational
Detection window
50 pg/mL LOD in urine; stable metabolite extends detectionCox 2015
WADA-banned; anti-doping testing available.
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Oral bioavailability
Demonstrated efficacy in animal oral administrationNg 2000
Potential for oral therapeutic development.
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Endogenous expression
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Constitutive in neutrophils, epithelial tissues
Upregulated during infection and inflammation.Pinheiro 2026
Exogenous (experimental)
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Dose varies by study; antimalarial ~10–50 μM in vitro
No FDA-approved exogenous formulation.
03Metabolic / Fat Loss Evidence
Parameter
HGH Fragment 176-191
LL-37
Weight gain reduction
50% reduction vs control (15.8 ± 0.6 g vs 35.6 ± 0.8 g)Ng 2000
Obese Zucker rats, 19 days oral administration.
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Body fat reduction
Significant decrease in body weight and body fat in obese mice (14 days)Heffernan 2001
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Lipolytic activity
Increased adipose tissue lipolytic activityNg 2000
Direct measurement in treated animals.
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Insulin sensitivity
No adverse effect — euglycemic clamp confirmedNg 2000
Contrasts with intact hGH diabetogenic effects.
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IGF-1 impact
No elevation — fragment does not activate GH/IGF-1 axis
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Beta-3 AR dependency
Effect abolished in β3-AR knockout miceHeffernan 2001
Confirms β3-AR as primary mechanism.
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Human evidence
None published — pre-clinical only
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04Side Effects & Safety
Parameter
HGH Fragment 176-191
LL-37
Human safety data
Not available — no published human trials
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Metabolic profile
Six metabolites identified; CRSVEGSCG most stableCox 2015
Detection window implications for doping control.
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Cytotoxicity (high dose)
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Membrane disruption in host cells at supraphysiological concentrations
Pro-inflammatory signaling
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Can exacerbate inflammation in certain contexts (context-dependent)Pinheiro 2026
Theoretical cancer risk
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Immunomodulatory roles in tumor microenvironment under investigation
Absolute Contraindications
HGH Fragment 176-191
- ·Competitive athletes (WADA-banned)Cox 2015
LL-37
—Relative Contraindications
HGH Fragment 176-191
- ·Absence of human safety data — experimental use only
LL-37
- ·Active autoimmune disease (theoretical immune dysregulation)
05Administration Protocol
Parameter
HGH Fragment 176-191
LL-37
1. Route
Subcutaneous injection primary route in research context. Oral administration demonstrated efficacy in animal models at 500 mcg/kg.
LL-37 is constitutively expressed in neutrophils and epithelial cells, cleaved from hCAP-18 by proteinase-3 at sites of infection or inflammation.
2. Frequency
Once daily dosing used in animal studies. Timing not specified; GH-independent mechanism suggests flexibility.
Synthetic LL-37 and derivatives (e.g., SAMP-12aa) tested in vitro and animal models. Administered via topical, intraperitoneal, or intravenous routes in research settings.
3. Duration
Animal protocols: 14–19 days. Human duration not established — no published trials.
LL-37 is resistant to pepsin degradation at gastric pH. Synthetic short peptides designed to retain this stability while reducing toxicity.Lu 2026
4. Storage
Lyophilized peptide storage per standard peptide protocols. Metabolite stability suggests refrigerated reconstituted solution viable.
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5. Detection
Detectable in urine via SPE-LC-MS at 50 pg/mL LOD. Extended detection window via stable metabolite CRSVEGSCG.Cox 2015
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