Side-by-side · Research reference
GHRP-2vsLL-37
Side-by-side comparison across mechanism, dosage, evidence, side effects, administration, and stack synergies. Citations on every claim where available.
APhase 2HUMAN-REVIEWED15/42 cited
BHuman-MechanisticHUMAN-REVIEWED15/35 cited
GHRP-2
Hexapeptide GHRP · Phase 2 (clinical diagnostic)
SQ · Multiple sites · 1–3×/day
LL-37
Cathelicidin · Human AMP
Broad-spectrumAntimicrobial activity
Endogenous · Secreted at inflammation sites
01Mechanism of Action
Parameter
GHRP-2
LL-37
Primary target
Ghrelin receptor (GHS-R1a) on anterior pituitaryBowers 1990
Pathway
GHS-R1a → Gαq → Ca²⁺ → GH vesicle exocytosisBowers 2002
hCAP-18 precursor → Proteinase-3 cleavage → LL-37 release → Membrane insertion/disruption
Downstream effect
Strong GH pulse + IGF-1 elevation; appetite increase via ghrelin agonismBowers 2002
Membrane permeabilization, cytokine induction, autophagy, phagosome-lysosome fusion, chemotaxisAhmad 2026Zhang 2026
Feedback intact?
Yes, with somatostatin feedback active
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Origin
Synthetic hexapeptide; developed by Bowers/Tulane group in the 1980sBowers 1990
Endogenous human cathelicidin (37-AA fragment, residues 134–170 of hCAP-18)
Antibody development
—
—
02Dosage Protocols
Parameter
GHRP-2
LL-37
Frequency
1–3× per day
—
Lower / starter dose
50 mcg per dose
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Evidence basis
Phase 2 + clinical diagnostic useBowers 1990
In vitro, animal models, human observational
Duration
8–12 weeks on / 4 off (anecdotal)
—
Reconstitution
Bacteriostatic water
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Timing
Pre-sleep + fasted preferred
—
Endogenous expression
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Constitutive in neutrophils, epithelial tissues
Upregulated during infection and inflammation.Pinheiro 2026
Exogenous (experimental)
—
Dose varies by study; antimalarial ~10–50 μM in vitro
No FDA-approved exogenous formulation.
04Side Effects & Safety
Parameter
GHRP-2
LL-37
Prolactin elevation
Mild but measurable
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Hunger
Strong appetite increase
—
Injection site reaction
Mild erythema
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IGF-1 elevation
Strong; monitor with chronic high-dose use
—
Cancer risk
Contraindicated in active malignancy
—
Pregnancy / OB
Avoid
—
Cytotoxicity (high dose)
—
Membrane disruption in host cells at supraphysiological concentrations
Pro-inflammatory signaling
—
Can exacerbate inflammation in certain contexts (context-dependent)Pinheiro 2026
Theoretical cancer risk
—
Immunomodulatory roles in tumor microenvironment under investigation
Absolute Contraindications
GHRP-2
- ·Active malignancy
- ·Pregnancy / breastfeeding
LL-37
—Relative Contraindications
GHRP-2
- ·Untreated diabetes
LL-37
- ·Active autoimmune disease (theoretical immune dysregulation)
05Administration Protocol
Parameter
GHRP-2
LL-37
1. Reconstitution
Add 2 mL bacteriostatic water to 5 mg vial → 2.5 mg/mL.
LL-37 is constitutively expressed in neutrophils and epithelial cells, cleaved from hCAP-18 by proteinase-3 at sites of infection or inflammation.
2. Injection site
SQ — abdomen or thigh. Rotate sites.
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. Timing
Pre-sleep + fasted preferred.
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
Lyophilised: room temp, light-protected. Reconstituted: refrigerate ≤30 days.
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5. Needle
29–31G, 4–8 mm insulin syringe.
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06Stack Synergy
GHRP-2
+ CJC-1295 (no DAC)
StrongGHRP-2 + CJC-1295-no-DAC is a higher-amplitude alternative to the ipamorelin + CJC-1295 stack. GHRP-2 produces a stronger pulse but with cortisol + prolactin signal — choose when maximum GH amplitude is the goal and the side-effect tolerance is acceptable.
- GHRP-2
- 100–200 mcg SQ · pre-sleep
- CJC-1295 (no DAC)
- 100 mcg SQ · same injection
- Primary benefit
- High-amplitude GH pulse, body composition
LL-37
— no documented stacks