LL-37 5mg: The Complete Research Guide — Peptide Dosage, Nasal Spray, and Where to Buy LL-37

Name: LL-37 5mg Peptide: Dosage, Nasal Spray & Where to Buy
Brand: ll 37 nasal spray
SKU: LL-37-5mg
Price: 86.00 USD
Availability: InStock

LL-37 5mg is rapidly becoming one of the most discussed antimicrobial peptides in contemporary immunology and infection biology research. As a member of the cathelicidin family of host defence peptides, LL-37 has attracted intense scientific interest for its broad-spectrum antimicrobial activity, immunomodulatory properties, and potential applications in wound healing, respiratory research, and inflammatory disease models. This comprehensive guide covers everything researchers need to know about LL-37 5mg: its molecular identity, mechanism of action, correct LL-37 peptide dosage frameworks, LL-37 nasal spray protocols, and how to identify where to buy LL-37 peptide from a quality-verified, research-grade source.

What Is LL-37 5mg?

LL-37 is the only known member of the human cathelicidin family. It is a 37-amino acid cationic antimicrobial peptide derived from the C-terminal domain of the precursor protein hCAP18 (human Cationic Antimicrobial Protein 18), which is encoded by the CAMP gene. The designation “LL-37” reflects both the peptide’s length (37 amino acids) and the two leucine (L) residues at its N-terminus.

In research settings, LL-37 5mg refers to the standard vial size in which this peptide is commercially supplied — 5 milligrams of lyophilised LL-37 acetate per vial — which provides a sufficient quantity for multiple dosing cycles in preclinical research protocols.

Molecular Profile of LL-37 5mg

Full Name: Cathelicidin LL-37 / Human Cathelicidin Antimicrobial Peptide
Amino Acid Sequence: LLGDFFRKSKEKIGKEFKRIVQRIKDFLRNLVPRTES
Amino Acid Count: 37
Molecular Formula: C₂₀₅H₃₄₀N₆₀O₅₃S
Molecular Weight: 4,493.3 Da
CAS Number: 154947-66-7
Common Salt Form: LL-37 acetate
Isoelectric Point (pI): ~11 (highly cationic)
Solubility: Soluble in water and aqueous buffers; best reconstituted in sterile water or PBS
Standard Vial Size: LL-37 5mg (research supply)
Storage Form: Lyophilised powder

How Does LL-37 Work? Mechanisms of Action

Understanding the multilayered biology of LL-37 is essential for designing reproducible research protocols and interpreting experimental outcomes. LL-37 operates through several distinct mechanisms depending on the biological system under study.

Direct Antimicrobial Activity

The primary mechanism of LL-37 is direct membrane disruption of bacterial cells. As a cationic, amphipathic alpha-helical peptide, LL-37 is electrostatically attracted to the negatively charged outer membranes of both Gram-positive and Gram-negative bacteria. Upon contact, it inserts into and disrupts the bacterial lipid bilayer through a “carpet model” or toroidal pore-forming mechanism, leading to rapid membrane depolarisation, loss of osmotic integrity, and bacterial cell death.

LL-37 5mg has demonstrated research activity against a broad spectrum of pathogens including:

Gram-negative bacteria: E. coli, Pseudomonas aeruginosa, Klebsiella pneumoniae
Gram-positive bacteria: Staphylococcus aureus (including MRSA), Streptococcus pneumoniae
Fungi: Candida albicans
Enveloped viruses: Influenza A, RSV, HIV-1 (in vitro models)
Bacterial biofilms: LL-37 disrupts established biofilm architecture at sub-MIC concentrations

Immunomodulatory and Anti-Inflammatory Activity

Beyond its direct antimicrobial effects, LL-37 functions as a potent immunomodulator. It binds to formyl peptide receptor-like 1 (FPRL1/FPR2) on immune cells, triggering chemotaxis of neutrophils, monocytes, and T-lymphocytes to sites of infection and tissue damage. Simultaneously, LL-37 modulates the LPS-induced TLR4 inflammatory cascade by neutralising lipopolysaccharide (LPS), thereby attenuating excessive inflammatory responses — a property of significant interest in sepsis and endotoxaemia research.

Wound Healing and Tissue Repair

LL-37 stimulates keratinocyte migration and proliferation through EGFR transactivation, accelerating re-epithelialisation in wound models. It also promotes angiogenesis by upregulating VEGF expression, and has demonstrated activity in promoting the recruitment of dermal fibroblasts to wound sites. These properties make LL-37 5mg a highly relevant research tool in wound biology, burn healing, and skin barrier repair science.

Antiviral and Mucosal Defence Research

LL-37 is constitutively expressed in human respiratory epithelium and is a primary component of innate mucosal immunity. Research has shown LL-37 to neutralise viral envelope proteins and inhibit viral attachment to host cell receptors. This activity has driven growing research interest in LL-37 nasal spray formulations as a potential respiratory mucosal defence tool — an area of particularly active investigation since 2020.

Anti-Cancer and Anti-Tumour Research

Emerging research indicates that LL-37 exerts context-dependent effects on tumour biology. In certain cancer models (ovarian, lung, breast), LL-37 has demonstrated pro-tumorigenic effects via FPR2 and EGFR signalling. In others (colon, haematological cancers), LL-37 exhibits anti-proliferative and pro-apoptotic activity. This duality makes LL-37 an important subject in cancer biology research, with nuanced implications depending on tumour type and microenvironment.

LL-37 Peptide Dosage: Research Frameworks

The correct LL-37 peptide dosage is one of the most commonly researched topics by scientists entering this field. Because LL-37 operates across multiple biological systems — antimicrobial, immunomodulatory, wound healing — LL-37 dosage recommendations differ meaningfully depending on the research model and route of administration.

The following LL-37 peptide dosage information is provided for scientific and educational purposes only and does not constitute medical advice.

Subcutaneous LL-37 Dosage (Systemic Research Protocols)

For systemic research models examining immune modulation, anti-inflammatory activity, or wound healing, subcutaneous (SubQ) injection is the most widely reported route. The commonly referenced LL-37 dosage range for subcutaneous administration is:

Low-dose exploratory protocol: 100–200 mcg per injection, once daily
Standard systemic protocol: 200–400 mcg per injection, once or twice daily
High-dose investigational protocol: 400–600 mcg per injection (with close monitoring of inflammatory markers)

Typical research cycle duration for subcutaneous LL37 peptide dosage protocols ranges from 2–6 weeks, followed by a rest period to assess physiological response.

Intravenous LL-37 Dosage (In Vivo Sepsis and Endotoxaemia Models)

In sepsis and LPS-challenge research models, LL-37 5mg is frequently administered intravenously. Reported LL-37 peptide dosage ranges in murine sepsis models typically span 1–10 mg/kg body weight, administered as a single bolus or divided doses depending on the study design. Human equivalent dose extrapolations using established allometric scaling methods should be applied carefully and referenced against current literature

LL-37 Nasal Spray Dosage

The LL-37 nasal spray route is among the most actively researched delivery formats, particularly in models examining upper respiratory tract infection, mucosal immunity, rhinosinusitis, and viral challenge. LL-37 nasal spray protocols allow direct delivery of the peptide to nasal mucosa and respiratory epithelium, where LL-37 is naturally expressed.

Reported LL-37 peptide dosage frameworks for nasal spray administration include:

Concentration range: 100–500 mcg/mL in sterile saline or PBS vehicle
Volume per nostril: 100 µL per actuation (standard nasal spray device)
Frequency: Once to twice daily application in most published mucosal research protocols
Cycle duration: 1–4 weeks per study period

For LL-37 nasal spray formulations, isotonic saline (0.9% NaCl) or phosphate-buffered saline (PBS, pH 7.4) is the recommended vehicle to preserve peptide structural integrity and mucosal tolerability.

Reconstitution of LL-37 5mg for Research Use

For a LL-37 5mg vial, standard reconstitution guidelines:

LL-37 5mg + 5 mL sterile water = 1,000 mcg/mL (1 mcg/µL)
LL-37 5mg + 2.5 mL sterile water = 2,000 mcg/mL (2 mcg/µL)
LL-37 5mg + 10 mL sterile saline = 500 mcg/mL (for nasal spray vehicle preparation)

Use polypropylene or low-binding tubes for reconstituted LL-37 solutions, as the peptide’s cationic nature makes it prone to non-specific adsorption on glass and polystyrene surfaces. A U-100 insulin syringe ensures precision at microgram-level LL-37 dosage measurements.

LL-37 Peptide Dosage Summary Table

Administration Route	Dose Range	Frequency	Common Research Context
Subcutaneous	100–600 mcg	Once–twice daily	Immune modulation, wound healing
Intravenous	1–10 mg/kg	Single or divided	Sepsis, endotoxaemia models
LL-37 Nasal Spray	100–500 mcg/mL	Once–twice daily	Mucosal immunity, respiratory research
Topical	10–100 mcg/cm²	Once–twice daily	Wound healing, skin barrier studies
Intranasal (animal)	50–200 mcg/kg	Once daily	Viral challenge, CNS-mucosal axis research

LL-37 Nasal Spray: Research Applications and Formulation Considerations

The LL-37 nasal spray delivery format has attracted substantial scientific interest, particularly following research highlighting the role of cathelicidins in nasal mucosal defence against respiratory pathogens.

Scientific Rationale for LL-37 Nasal Spray

In healthy individuals, LL-37 is constitutively expressed by nasal epithelial cells, submucosal glands, and infiltrating neutrophils as part of the innate mucosal immune barrier. Research has shown that individuals with reduced nasal LL-37 expression demonstrate increased susceptibility to upper respiratory infections. Exogenous LL-37 nasal spray administration in research models aims to restore or augment this innate barrier function.

Key research applications of LL-37 nasal spray include:

Viral neutralisation at the nasal mucosal surface (influenza, RSV, SARS-CoV-2 models)
Disruption of nasal biofilms in chronic rhinosinusitis research
Modulation of nasal microbiome composition
Innate immune priming prior to pathogen challenge in infection biology studies

Formulation Stability of LL-37 Nasal Spray

Maintaining peptide integrity in LL-37 nasal spray formulations requires careful attention to:

pH: LL-37 is most stable at pH 6.5–7.4; formulations outside this range risk aggregation and reduced bioactivity
Ionic strength: Low ionic strength buffers (10–50 mM PBS) are preferred over high-salt vehicles that can promote peptide aggregation
Preservative-free formulations: For short-term research use, preservative-free saline is preferred; benzalkonium chloride (a common nasal spray preservative) has been shown to reduce LL-37 bioactivity at certain concentrations
Temperature during use: Reconstituted LL-37 nasal spray solutions should be stored at 2–8°C and allowed to reach room temperature immediately before administration

Where to Buy LL-37 Peptide: Sourcing Guide for Researchers

For researchers deciding where to buy LL-37 peptide, the quality of the source is directly tied to the scientific validity and reproducibility of research outcomes. Whether you are searching to buy LL-37 peptide for immunology, antimicrobial, wound healing, or respiratory research, the following criteria are non-negotiable.

What to Verify Before You Buy LL-37 Peptide

Certificate of Analysis from an Accredited Laboratory

Any supplier from whom you buy LL-37 peptide must provide a current, batch-specific Certificate of Analysis (CoA) from an independent, ISO-accredited analytical laboratory. For LL-37 5mg, the CoA must confirm:

Purity ≥98% by HPLC (reverse-phase)
Correct molecular weight (4,493.3 Da) confirmed by ESI-MS or MALDI-TOF mass spectrometry
Amino acid sequence confirmation (critical for a 37-amino acid peptide where sequence errors directly negate bioactivity)
Endotoxin level <1 EU/mg — essential for any in vivo or cell-based research
Salt form confirmation: LL-37 acetate (TFA-free, confirming complete counter-ion exchange)
Residual solvent testing

Correct LL-37 5mg Vial Specification

When you buy LL-37 peptide in the 5mg format, verify the following product specifications on the supplier’s documentation:

Supplied as lyophilised (freeze-dried) powder
Packaged under nitrogen or inert atmosphere to prevent oxidation
Correctly labelled with CAS number (154947-66-7), molecular weight, lot number, and expiry date
Adequate cold chain shipping confirmed (ice packs, insulated packaging for ambient temperatures above 15°C)

Sequence Verification Is Non-Negotiable for LL-37

Unlike shorter peptides of 6–10 amino acids, LL-37’s 37-amino acid sequence leaves significant room for synthesis error. When selecting where to buy LL-37 peptide or searching for LL-37 peptide for sale, always request MS/MS sequence fragmentation data in addition to basic HPLC purity data to confirm correct amino acid identity across the full peptide chain.

LL-37 Peptide for Sale: Market Quality Landscape

The LL-37 peptide for sale market varies considerably in quality. At the premium end, specialist research peptide suppliers provide full analytical packages, sterile lyophilised product, verified cold chain logistics, and responsive technical support. At the lower end, unverified suppliers may offer LL37 peptide buy options at significantly reduced prices, often without adequate CoA documentation, correct salt form specification, or endotoxin testing.

For any researcher searching for LL-37 peptide for sale, a price point significantly below the market average (~$150–$350 per 5mg for research-grade product) is a reliable indicator of compromised purity, insufficient testing, or underdosed product.

Red Flags When Looking for LL-37 Peptide for Sale

No HPLC or mass spectrometry data available
CoA not batch-specific (generic document used across multiple lots)
No endotoxin testing data
Pre-dissolved liquid LL-37 without sterility certification
No sequence confirmation for a peptide of this length
Therapeutic or clinical claims about the peptide
Anonymous supplier with no verifiable address or regulatory information

Storage After You Buy LL-37 Peptide

Correct storage after you buy LL-37 peptide is critical to maintaining bioactivity for the duration of your research:

Lyophilised LL-37 5mg powder: −20°C for up to 24 months; 2–8°C for up to 6 months
Reconstituted LL-37 solution: 2–8°C for up to 2–3 weeks; do not freeze reconstituted solution
LL-37 nasal spray solution: Prepare fresh from lyophilised stock for each study period; use within 7–14 days when stored at 2–8°C
Avoid repeated freeze-thaw cycles: LL-37 aggregates with mechanical disruption; prepare single-use aliquots from the reconstituted stock where possible

LL-37 5mg: Research Applications Summary

LL-37 5mg is relevant across a uniquely broad landscape of biomedical research domains. Key areas where LL-37 peptide dosage protocols are actively being investigated include:

Infectious Disease and Antimicrobial Resistance Research

LL-37’s membrane-disrupting mechanism operates independently of the resistance pathways targeted by conventional antibiotics, making LL-37 5mg highly relevant in antibiotic-resistant pathogen research. Studies examining LL-37 activity against MRSA, carbapenem-resistant Pseudomonas, and multi-drug-resistant Acinetobacter are among the most frequently published applications.

Respiratory Mucosal Immunity

The LL-37 nasal spray delivery model has positioned this peptide as a key tool in studying mucosal innate immunity in the upper and lower respiratory tract. Research interest has intensified around LL-37’s role in pandemic-relevant respiratory pathogen defence, with multiple groups investigating LL-37 nasal spray protocols in viral challenge models.

Wound Healing and Dermatology

LL-37 5mg is widely used in keratinocyte migration assays, full-thickness wound models, and diabetic wound healing research. The LL-37 peptide dosage for topical wound healing applications ranges from 10–100 mcg/cm² of wound surface area in published preclinical studies

Autoimmune and Inflammatory Disease Models

LL-37 forms complexes with self-nucleic acids (DNA, RNA) that can activate intracellular TLR7, TLR8, and TLR9 receptors, bypassing normal extracellular immune checkpoints. This property has made LL-37 a central focus in psoriasis, lupus, and rheumatoid arthritis research, where dysregulated cathelicidin signalling is implicated in disease pathogenesis.

Frequently Asked Questions About LL-37 5mg

What is the correct LL-37 peptide dosage for subcutaneous research?

The most commonly referenced LL-37 peptide dosage for subcutaneous systemic research is 200–400 mcg per injection, administered once or twice daily. LL-37 dosage should always be calibrated against the specific research endpoint and biological model in use

How do I prepare an LL-37 nasal spray from a 5mg vial?

To prepare an LL-37 nasal spray at 500 mcg/mL, reconstitute the LL-37 5mg vial in 10 mL of sterile isotonic saline (pH 7.0–7.4). Transfer to a sterile nasal spray device immediately before use and store at 2–8°C for up to 7–14 days.

Where can I find LL-37 peptide for sale?

Researchers looking for LL-37 peptide for sale should prioritise suppliers who provide HPLC and mass spectrometry CoAs, sequence verification data, endotoxin testing, and confirmed acetate salt form. Look for the standard LL-37 5mg vial specification with lyophilised, nitrogen-packed supply.

What is the difference between LL-37 dosage routes?

LL-37 dosage varies substantially by route. Subcutaneous dosing for systemic effects typically falls at 100–600 mcg per injection. LL-37 nasal spray protocols use 100–500 mcg/mL concentrations delivered topically. IV dosing in sepsis models operates at mg/kg ranges. Each route targets distinct biological compartments and requires independent LL37 peptide dosage calibration.

Is LL-37 the same as cathelicidin?

Yes. LL-37 is the sole human cathelicidin. It is often referred to interchangeably as LL-37, cathelicidin LL-37, hCAP18/LL-37, or human cathelicidin antimicrobial peptide, depending on the research context.

Conclusion: LL-37 5mg as a Foundational Research Peptide

LL-37 5mg occupies a unique position in peptide research — it is simultaneously an antimicrobial agent, an immunomodulator, a wound healing promoter, and an innate mucosal defence molecule. Its versatility across biological systems, combined with its status as the only human cathelicidin, makes it indispensable for researchers working at the intersection of microbiology, immunology, and translational medicine.

Whether your research demands precise LL-37 peptide dosage calibration for a subcutaneous systemic protocol, a carefully formulated LL-37 nasal spray for mucosal defence studies, or simply reliable guidance on where to buy LL-37 peptide from a quality-verified source, the principles outlined in this guide provide a rigorous foundation for principled, reproducible research using LL-37 5mg.

Always source LL-37 peptide for sale from suppliers who provide complete, independently verified analytical documentation — the integrity of your research depends on the integrity of your peptide.

Disclaimer: The products mentioned are not intended for human or animal consumption. Research chemicals are intended solely for laboratory experimentation and/or in-vitro testing. Bodily introduction of any sort is strictly prohibited by law. All purchases are limited to licensed researchers and/or qualified professionals. All information shared in this article is for educational purposes only.

References

Gordon YJ, Huang LC, Romanowski EG, Yates KA, Proske RJ, McDermott AM. Human cathelicidin (LL-37), a multifunctional peptide, is expressed by ocular surface epithelia and has potent antibacterial and antiviral activity. Curr Eye Res. 2005 May;30(5):385-94. doi: 10.1080/02713680590934111. PMID: 16020269; PMCID: PMC1497871.
Alalwani SM, Sierigk J, Herr C, Pinkenburg O, Gallo R, Vogelmeier C, Bals R. The antimicrobial peptide LL-37 modulates the inflammatory and host defense response of human neutrophils. Eur J Immunol. 2010 Apr;40(4):1118-26. doi: 10.1002/eji.200939275. PMID: 20140902; PMCID: PMC2908514.
Kahlenberg JM, Kaplan MJ. Little peptide, big effects: the role of LL-37 in inflammation and autoimmune disease. J Immunol. 2013 Nov 15;191(10):4895-901. doi: 10.4049/jimmunol.1302005. PMID: 24185823; PMCID: PMC3836506.
Reinholz M, Ruzicka T, Schauber J. Cathelicidin LL-37: an antimicrobial peptide with a role in inflammatory skin disease. Ann Dermatol. 2012 May;24(2):126-35. doi: 10.5021/ad.2012.24.2.126. Epub 2012 Apr 26. PMID: 22577261; PMCID: PMC3346901.
Kusaka; et al. Expression of human cathelicidin peptide LL-37 in inflammatory bowel disease. Clin Exp Immunol. 2018 Jan;19(11). Epub 2017 Sep 28. https://pubmed.ncbi.nlm.nih.gov/28872665/
Golec M. Cathelicidin LL-37: LPS-neutralizing, pleiotropic peptide. Ann Agric Environ Med. 2007;14(1):1-4. PMID: 17655171.
Moreno-Angarita A, Aragón CC, Tobón GJ. Cathelicidin LL-37: A new important molecule in the pathophysiology of systemic lupus erythematosus. J Transl Autoimmun. 2019 Dec 17;3:100029. doi: 10.1016/j.jtauto.2019.100029. PMID: 32743514; PMCID: PMC7388365.
Singh D, Vaughan R, Kao CC. LL-37 peptide enhancement of signal transduction by Toll-like receptor 3 is regulated by pH: identification of a peptide antagonist of LL-37. J Biol Chem. 2014 Oct 3;289(40):27614-24. doi: 10.1074/jbc.M114.582973. Epub 2014 Aug 4. PMID: 25092290; PMCID: PMC4183800.
Piktel E, Niemirowicz K, Wnorowska U, Wątek M, Wollny T, Głuszek K, Góźdź S, Levental I, Bucki R. The Role of Cathelicidin LL-37 in Cancer Development. Arch Immunol Ther Exp (Warsz). 2016 Feb;64(1):33-46. doi: 10.1007/s00005-015-0359-5. Epub 2015 Sep 22. PMID: 26395996; PMCID: PMC4713713.
Salvado MD, Di Gennaro A, Lindbom L, Agerberth B, Haeggström JZ. Cathelicidin LL-37 induces angiogenesis via PGE2-EP3 signaling in endothelial cells, in vivo inhibition by aspirin. Arterioscler Thromb Vasc Biol. 2013 Aug;33(8):1965-72. doi: 10.1161/ATVBAHA.113.301851. Epub 2013 Jun 13. PMID: 23766266.
Ramos R, Silva JP, Rodrigues AC, Costa R, Guardão L, Schmitt F, Soares R, Vilanova M, Domingues L, Gama M. Wound healing activity of the human antimicrobial peptide LL37. Peptides. 2011 Jul;32(7):1469-76. doi: 10.1016/j.peptides.2011.06.005. Epub 2011 Jun 13. https://pubmed.ncbi.nlm.nih.gov/21693141/
Takahashi, T., Kulkarni, N.N., Lee, E.Y. et al. Cathelicidin promotes inflammation by enabling binding of self-RNA to cell surface scavenger receptors. Sci Rep 8, 4032 (2018). https://doi.org/10.1038/s41598-018-22409-3

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