Side-by-side · Research reference

GHRP-6vsLL-37

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

APhase 1HUMAN-REVIEWED10/36 cited

BHuman-MechanisticHUMAN-REVIEWED15/35 cited

GHRP-6

Hexapeptide GHRP · Strong appetite stimulant

100–200 mcgPer doseBowers 1990

Phase 1Evidence levelBowers 1990

~15 minHalf-lifeMalagón 1999

SQ · Multiple sites · 1–3×/day

LL-37

Cathelicidin · Human AMP

Broad-spectrumAntimicrobial activity

Membrane disruptionPrimary mechanismLu 2026 He 2026

Innate immunityHost defense rolePinheiro 2026 Zhang 2026

Endogenous · Secreted at inflammation sites

01Mechanism of Action

Parameter

GHRP-6

LL-37

Primary target

Ghrelin receptor (GHS-R1a)Bowers 1990

Bacterial membranes · Phosphatidylserine-exposed cellsHe 2026 Lu 2026

Pathway

GHS-R1a → Gαq → Ca²⁺ → GH release; central appetite driveBowers 2002

hCAP-18 precursor → Proteinase-3 cleavage → LL-37 release → Membrane insertion/disruption

Downstream effect

GH pulse + strong appetite stimulation; modest IGF-1 elevationBowers 2002

Membrane permeabilization, cytokine induction, autophagy, phagosome-lysosome fusion, chemotaxisAhmad 2026 Zhang 2026

Feedback intact?

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Origin

Synthetic hexapeptide; first-generation GHRP from Bowers groupBowers 1990

Endogenous human cathelicidin (37-AA fragment, residues 134–170 of hCAP-18)

Antibody development

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02Dosage Protocols

Parameter

GHRP-6

LL-37

Standard dose

100–200 mcg per injectionBowers 1990

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Frequency

1–3× per day

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Lower / starter dose

50 mcg per dose

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Evidence basis

Phase 1 + clinical practiceBowers 1990

In vitro, animal models, human observational

Duration

8–12 weeks on / 4 off

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Reconstitution

Bacteriostatic water

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Timing

Pre-meal preferred for appetite support

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Half-life

~15 minMalagón 1999

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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.

Plasma levels (malaria)

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Elevated in infected patients and miceHe 2026

Exogenous administration reduced parasitemia in murine models.He 2026

04Side Effects & Safety

Parameter

GHRP-6

LL-37

Hunger

Pronounced — defining feature vs ipamorelin

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Cortisol elevation

Mild

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Prolactin elevation

Mild

—

Injection site reaction

Mild

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Cancer risk

Contraindicated in active malignancy

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Pregnancy / OB

Avoid

—

Cytotoxicity (high dose)

—

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

Biofilm formation risk

—

LL-37-DNA complexes may stabilize dental plaque biofilmsTanabe 2026

Theoretical cancer risk

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Immunomodulatory roles in tumor microenvironment under investigation

Absolute Contraindications

GHRP-6

·Active malignancy
·Pregnancy / breastfeeding

LL-37

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Relative Contraindications

GHRP-6

·Severe insulin resistance (appetite-driven caloric load)

LL-37

·Active autoimmune disease (theoretical immune dysregulation)

05Administration Protocol

Parameter

GHRP-6

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. 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-meal for appetite support; pre-sleep for GH alignment.

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. Reconstituted: refrigerate ≤30 days.

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5. Needle

29–31G, 4–8 mm insulin syringe.

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