Side-by-side · Research reference

LL-37vsSermorelin

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

AHuman-MechanisticHUMAN-REVIEWED15/35 cited

BPhase 3HUMAN-REVIEWED14/43 cited

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

Sermorelin

GHRH 1-29 fragment · Short-acting

100–500 mcgPer doseMolteno 2013

Phase 3Evidence levelWalker 1994 Molteno 2013

~12 minHalf-lifeMolteno 2013

SQ · Pre-sleep · 1×/day

01Mechanism of Action

Parameter

LL-37

Sermorelin

Primary target

Bacterial membranes · Phosphatidylserine-exposed cellsHe 2026 Lu 2026

Pituitary GHRH receptorWalker 1994

Pathway

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

GHRH-R → Gαs → cAMP → PKA → GH vesicle exocytosisWalker 1994

Downstream effect

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

Pulsatile GH release; subsequent IGF-1 elevationMolteno 2013

Feedback intact?

—

Yes — short pulse preserves feedback

Origin

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

Unmodified active 29-AA fragment of human GHRH (1-44)Walker 1994

Antibody development

—

02Dosage Protocols

Parameter

LL-37

Sermorelin

Endogenous expression

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.

—

Plasma levels (malaria)

Elevated in infected patients and miceHe 2026

Exogenous administration reduced parasitemia in murine models.He 2026

—

Evidence basis

In vitro, animal models, human observational

Phase 3 (Geref pediatric); clinical practiceWalker 1994 Molteno 2013

Standard dose

—

100–500 mcg per injectionMolteno 2013

Frequency

—

Once daily, pre-sleep

Lower / starter dose

—

100 mcg per dose

Duration

—

8–12 weeks per cycle

Reconstitution

—

Bacteriostatic water

Timing

—

Pre-sleep, fasted preferred

Half-life

—

~12 min (plasma)Molteno 2013

Shorter than tesamorelin (~26 min) — simpler GHRH analogue.

04Side Effects & Safety

Parameter

LL-37

Sermorelin

Cytotoxicity (high dose)

Membrane disruption in host cells at supraphysiological concentrations

—

Pro-inflammatory signaling

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

Immunomodulatory roles in tumor microenvironment under investigation

—

Injection site reaction

—

Mild erythema, transient pain

Flushing / headache

—

Common transient effect

IGF-1 elevation

—

Modest at standard doses

Cancer risk

—

Contraindicated in active malignancy (GH/IGF-1 axis)

Pregnancy / OB

—

Avoid

Glucose handling

—

Generally neutral

Absolute Contraindications

LL-37

—

Sermorelin

·Active malignancy
·Pregnancy / breastfeeding
·Disrupted hypothalamic-pituitary axis

Relative Contraindications

LL-37

·Active autoimmune disease (theoretical immune dysregulation)

Sermorelin

·Untreated diabetes

05Administration Protocol

Parameter

LL-37

Sermorelin

1. Natural secretion

LL-37 is constitutively expressed in neutrophils and epithelial cells, cleaved from hCAP-18 by proteinase-3 at sites of infection or inflammation.

Add 2 mL bacteriostatic water to 5 mg vial → 2.5 mg/mL = 250 mcg per 0.1 mL.

2. Experimental formulations

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.

SQ — abdomen or thigh. Rotate sites.

3. Stability considerations

LL-37 is resistant to pepsin degradation at gastric pH. Synthetic short peptides designed to retain this stability while reducing toxicity.Lu 2026

Pre-sleep, fasted.

4. Storage

—

Lyophilised: room temp, light-protected. Reconstituted: refrigerate ≤30 days.

5. Needle

—

29–31G, 4–8 mm insulin syringe.

06Stack Synergy

LL-37

— no documented stacks

Sermorelin

+ Ipamorelin

Strong

View Ipamorelin →

Sermorelin (GHRH analogue) and ipamorelin (selective GHRP) form the prototypical GHRH+GHRP dual-axis stack at the lowest cost. Both peak within 30 min and produce a sharp physiological GH pulse without cortisol/prolactin elevation.

Sermorelin: 200–300 mcg SQ · pre-sleep
Ipamorelin: 200–300 mcg SQ · same injection
Primary benefit: Pulsatile GH stimulation, recovery, body composition

Raun 1998 Walker 1994