LL-37

99%+ Purity USA Tested

Research Use Only. Not for Human or Veterinary Use

LL-37 (CAP-18): Human cathelicidin-derived host defense peptide with antimicrobial and immunomodulatory activity, CAS 154947-66-7, MW 4493.3 g/mol, ≥99% purity. Lyophilized powder for laboratory use.

$129.00

Peptide Name	LL-37 (CAP-18)
CAS Number	154947-66-7
Molecular Formula	C₂₀₅H₃₄₀N₆₀O₅₃
Molecular Weight	~4493.3 g/mol
Mechanism Class	Cathelicidin / host defense peptide (antimicrobial + immunomodulatory)
Appearance	White lyophilized powder
Purity	≥99% (HPLC)
Storage	-20°C, desiccated, protected from light
Solubility	Soluble in sterile water; avoid vigorous agitation upon reconstitution

This product is not intended for human or animal use. For scientific research only.

VivePeptides provides detailed analytical results including High-Performance Liquid Chromatography (HPLC) and mass spectrometry data for all peptides. These reports confirm peptide purity, composition, and molecular accuracy, giving researchers full transparency and confidence in the materials used for their studies.

All VivePeptides products undergo independent third-party laboratory testing to verify identity, purity, and consistency. This additional layer of quality control ensures that each peptide meets strict research-grade standards before being made available for laboratory use.

VivePeptides peptides should be stored in a cool, dry environment and protected from light and moisture. Lyophilized peptides are best kept refrigerated or frozen until use to maintain stability. Once reconstituted for research purposes, peptides should be stored according to standard laboratory protocols, typically under refrigeration, and handled using proper aseptic techniques to preserve integrity throughout the study period.

OVERVIEW

What Is LL-37 Peptide?

LL 37 is the only human cathelicidin antimicrobial peptide, a 37-amino-acid peptide derived from the C-terminal end of the precursor protein hCAP18 (human cationic antimicrobial protein 18 kDa), which is encoded by the CAMP gene. First characterized in the mid-1990s, LL 37 has become one of the most actively researched components of the human innate immune system, with hundreds of published studies exploring its antimicrobial, immunomodulatory, and tissue repair properties.

As a research peptide, LL 37 is classified as an antimicrobial peptide (AMP) with amphipathic, alpha-helical structure. It is naturally expressed in neutrophils, macrophages, epithelial cells, and various barrier tissues. Unlike conventional antibiotics that target specific bacterial processes, LL 37 research has demonstrated broad-spectrum activity through membrane disruption, biofilm inhibition, and direct immunomodulatory signaling. This multifunctional profile has positioned LL 37 as a central compound in antimicrobial peptide research and innate immunity studies.

Human Cathelicidin

The only cathelicidin-derived antimicrobial peptide in the human innate immune system

≥99% HPLC Purity

Every batch verified via high-performance liquid chromatography

USA Tested & Verified

Third-party analytical testing performed in USA laboratories

RESEARCH

LL 37 Mechanism of Action in Research

The LL 37 mechanism of action is notably multifunctional, extending well beyond simple antimicrobial activity. Research has identified at least four distinct functional domains within this peptide, making it one of the most versatile innate immune effectors studied in modern immunology.

Membrane Disruption and Antimicrobial Activity

LL 37’s primary antimicrobial mechanism involves direct disruption of microbial cell membranes. The peptide’s cationic charge and amphipathic alpha-helical structure allow it to preferentially bind to negatively charged bacterial membranes, forming pores and destabilizing membrane integrity. Research has demonstrated broad-spectrum activity against Gram-negative bacteria, Gram-positive bacteria, and certain fungi. Importantly, studies by Overhage et al. (2008) showed that LL 37 also inhibits bacterial biofilm formation at sub-inhibitory concentrations, a property that distinguishes it from most conventional antibiotics.

Immunomodulatory Signaling

Beyond direct antimicrobial effects, LL 37 functions as a potent immunomodulatory peptide. Research indicates it acts as a chemoattractant for neutrophils, monocytes, and T cells through activation of formyl peptide receptor-like 1 (FPRL-1) and purinergic receptor P2X7. Published studies by Yang et al. (1999) demonstrated LL 37’s ability to recruit immune cells to sites of infection and modulate the inflammatory response, bridging innate and adaptive immunity.

Wound Healing and Tissue Repair Pathways

LL 37 research has revealed significant involvement in wound healing processes. Studies indicate the peptide promotes keratinocyte migration and proliferation through activation of the epidermal growth factor receptor (EGFR) and downstream MAP/ERK signaling pathways. Heilborn et al. (2003) published findings demonstrating increased LL 37 expression at wound margins, suggesting a natural role in re-epithelialization and tissue repair.

COMPARISON

LL 37 vs BPC 157: Research Peptide Comparison

Both LL 37 and BPC 157 are studied for their protective properties in biological research, but they originate from different systems and operate through distinct mechanisms. LL 37 is an innate immune effector with direct antimicrobial activity, while BPC 157 is a gastric-derived peptide studied primarily for its cytoprotective properties. Understanding these differences helps researchers select the appropriate compound for their specific laboratory protocols.

Feature	LL 37	BPC 157
Origin	Human cathelicidin (hCAP18 C-terminus)	Human gastric juice protein fragment
Amino Acids	37	15
CAS Number	154947-66-7	137525-51-0
Molecular Weight	4493.4 Da	1419.5 Da
Primary Research Focus	Antimicrobial activity and innate immunity	Cytoprotective and tissue repair mechanisms
Structure	Alpha-helical, amphipathic, cationic	Stable across pH ranges
Proposed Mechanism	Membrane disruption, TLR signaling, EGFR	NO system, growth factor pathways
Research Volume	200+ published studies	100+ published studies

Both peptides are subjects of active investigation in tissue biology research. LL 37 is the primary compound for antimicrobial and innate immunity studies, while BPC 157 is preferred for cytoprotective and gastrointestinal research. VivePeptides offers both LL 37 and BPC 157 at research-grade purity from our USA-based facility.

RESEARCH STUDIES

LL 37 Research Applications & Published Studies

LL 37 research spans over two decades of published literature across microbiology, immunology, dermatology, and oncology. The following areas represent the most actively investigated applications. All references are to research contexts only.

Antimicrobial and Anti-Biofilm Research

LL 37 has been extensively studied for its activity against drug-resistant pathogens. Turner et al. (1998) published early characterizations of LL 37’s antimicrobial spectrum, and subsequent studies by Overhage et al. (2008) demonstrated its ability to inhibit and disrupt established bacterial biofilms. Research into LL 37’s anti-biofilm properties has gained significant attention as antibiotic resistance continues to present challenges in biomedical research.

Wound Biology and Dermatology Research

Published research has examined LL 37’s role in cutaneous wound healing. Heilborn et al. (2003) demonstrated increased cathelicidin expression during wound repair, and Carretero et al. (2008) published findings on LL 37’s effects on keratinocyte migration and proliferation. These studies have established LL 37 as a key peptide in skin biology and wound healing research.

Antiviral Research Applications

Recent LL 37 research has expanded into antiviral applications. Wang et al. (2021) published findings demonstrating LL 37’s interaction with the SARS-CoV-2 spike protein receptor binding domain and ACE2 receptor. These studies have opened new avenues of investigation into cathelicidin-derived peptides as tools for understanding host-pathogen interactions in viral disease research.

QUALITY ASSURANCE

Quality & Testing Standards

VivePeptides maintains rigorous quality control for every batch of LL 37 peptide. Our commitment to research-grade purity ensures that laboratories receive consistent, reliable compounds for their investigations.

HPLC & Mass Spectrometry

Every batch of LL 37 undergoes high-performance liquid chromatography (HPLC) and mass spectrometry analysis to confirm identity, purity, and molecular weight.

Third-Party Verified

All VivePeptides LL 37 is independently verified through third-party analytical laboratories based in the USA. Testing documentation is available for every lot.

≥99% Purity Standard

Our LL 37 consistently meets or exceeds ≥99% purity as determined by HPLC analysis, ensuring research-grade quality for laboratory applications.

FAQ

Frequently Asked Questions About LL 37

What is LL 37 used for in research?

LL 37 is used in research settings to study antimicrobial peptide activity, innate immune signaling, biofilm disruption, wound healing mechanisms, and immunomodulatory pathways. It is the only human cathelicidin and one of the most published antimicrobial peptides in the scientific literature. LL 37 is sold for research use only.

What purity is VivePeptides LL 37?

VivePeptides LL 37 is manufactured to ≥99% purity as verified by HPLC analysis. Every batch is tested and verified through independent third-party USA-based laboratories to ensure consistent research-grade quality.

How should LL 37 be stored?

Lyophilized LL 37 should be stored at -20°C, protected from light and moisture. Once reconstituted, the solution should be stored at 2 to 8°C and used within 7 to 14 days for optimal stability. LL 37 can be dissolved in sterile water, DMSO, or dilute acetic acid depending on research application. Avoid repeated freeze-thaw cycles.

What is the difference between LL 37 and other antimicrobial peptides?

LL 37 is unique as the only member of the cathelicidin family expressed in humans. Unlike many antimicrobial peptides that function solely through membrane disruption, LL 37 has been shown to also modulate immune cell recruitment, promote wound healing through EGFR activation, and regulate inflammatory responses through TLR signaling. This multifunctional profile distinguishes it from single-mechanism antimicrobial peptides.

Is VivePeptides LL 37 third-party tested?

Yes. Every lot of VivePeptides LL 37 undergoes independent third-party testing at USA-based analytical laboratories. Testing includes HPLC purity analysis and mass spectrometry identity confirmation. Results are available upon request for qualified researchers.

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