LL 37 Peptide Purity and Specification Guide for Cosmetic Formulation Sourcing

Core Molecular Specs & Technical Index

The ll 37 peptide, also known as cathelicidin LL-37, is a 37-amino acid antimicrobial peptide (AMP) derived from the human cathelicidin protein. For B2B buyers in cosmetic formulation and laboratory research, understanding its precise molecular specifications is the first step toward sourcing a reliable raw material. This peptide is characterized by its amphipathic alpha-helical structure, which enables it to interact with microbial membranes while maintaining stability in topical formulations. The core value for procurement professionals lies in its multifunctional profile: it supports skin barrier function, modulates inflammatory responses, and exhibits broad-spectrum antimicrobial activity without the resistance issues associated with conventional preservatives.

• Molecular Weight: 4493.3 Da (calculated monoisotopic mass), with a net positive charge (+6 at neutral pH) due to multiple arginine and lysine residues.
• Purity Grade: Minimum 95% by HPLC (High-Performance Liquid Chromatography) for cosmetic grade; 98%+ for research-grade applications. Impurities must be controlled below 0.5% per peak.
• Solubility Profile: Readily soluble in water (≥10 mg/mL) and phosphate-buffered saline (PBS). For lipid-based formulations, co-solvents like DMSO or ethanol may be required at concentrations below 1%.
• Storage Conditions: Lyophilized powder stable for 24 months at -20°C. Reconstituted solutions must be stored at -80°C and used within 6 months to prevent aggregation and loss of bioactivity.
• Sequence Verification: Full sequence (LLGDFFRKSKEKIGKEFKRIVQRIKDFLRNLVPRTES) confirmed by Edman degradation or mass spectrometry. Any truncation or deletion variants render the peptide inactive.

Industry data from the Peptide Therapeutics Foundation indicates that over 70% of commercial LL-37 batches fail purity specifications due to oxidation at methionine residues or incomplete deprotection during synthesis. Third-party HPLC analysis with a C18 column and UV detection at 214 nm is the industry standard for verifying batch-to-batch consistency.

Manufacturing & Quality Control

The production of high-purity ll 37 peptide follows a rigorous multi-step process designed to eliminate impurities while preserving the peptide's native conformation. Solid-phase peptide synthesis (SPPS) using Fmoc chemistry is the preferred method for commercial-scale production, as it allows precise control over amino acid coupling efficiency. After cleavage from the resin, the crude peptide undergoes preparative reverse-phase HPLC purification, where fractions are collected based on retention time windows that correspond to the full-length product. Quality control protocols include at least three orthogonal analytical methods: analytical HPLC for purity quantification, mass spectrometry for molecular weight confirmation, and amino acid analysis for composition verification. Third-party testing by ISO 17025 accredited laboratories is mandatory for batches intended for cosmetic or pharmaceutical use, with certificates of analysis (COA) provided for each lot.

• Production Process: SPPS with HBTU/HOBt activation, followed by TFA cleavage and ether precipitation. Yield optimization targets >60% crude purity before purification.
• Purification Method: Preparative HPLC using a C18 column with a linear gradient of acetonitrile in 0.1% TFA. Final purity >95% achieved after two sequential purification runs.
• Third-Party Testing: Independent laboratories perform endotoxin testing (LAL assay, <0.5 EU/mg), bioburden analysis, and stability studies under accelerated conditions (40°C/75% RH for 4 weeks).
• Certification List: COA (Certificate of Analysis), MSDS (Material Safety Data Sheet), allergen-free declaration, and heavy metals report (ICP-MS, <10 ppm total).
• Batch Traceability: Each batch assigned a unique lot number with full synthesis records, purification logs, and analytical data archived for 5 years.

Commercial Application Scenarios

In the cosmetic formulation industry, ll 37 peptide is increasingly incorporated into serums, creams, and masks targeting sensitive skin, acne-prone skin, and post-procedure recovery. At concentrations between 0.001% and 0.01% (10–100 ppm), it acts as a multifunctional active that supports skin microbiome balance while reducing visible redness and irritation. Formulators must consider the peptide's sensitivity to pH (optimal range 5.0–6.5) and avoid co-formulation with strong chelating agents like EDTA, which can sequester the zinc ions required for structural stability. For laboratory research, LL-37 is used in cell culture models to study wound healing, angiogenesis, and immune modulation, typically at concentrations of 1–10 µM in serum-free media. Bulk wholesale buyers, such as ingredient distributors and contract manufacturers, require consistent supply chains with lead times of 2–4 weeks and minimum order quantities (MOQs) of 1 gram for research-grade or 10 grams for cosmetic-grade material.

• Cosmetic Formulation: Ideal for leave-on products targeting barrier repair, acne management, and anti-aging. Compatible with glycerin, hyaluronic acid, and niacinamide.
• Lab Research: Used in ELISA-based quantification assays, antimicrobial susceptibility testing (MIC determination), and keratinocyte migration studies.
• Bulk Wholesale: Custom packaging options include 1g, 5g, and 10g vials with desiccant, or 100g–1kg drums for large-scale production.

ll 37 peptide VS Ordinary Low-Grade Peptides

Bulk Purchase Selection Guide

Procurement professionals sourcing ll 37 peptide for cosmetic or laboratory applications must navigate several common pitfalls to ensure they receive a product that meets specification. The most frequent issue is misrepresentation of purity: some suppliers quote ">95%" but use UV detection at 280 nm, which underestimates impurities compared to the standard 214 nm wavelength. Another trap is the use of non-GMP synthesis facilities that cannot provide batch-specific COAs or stability data. Buyers should always request a sample batch for in-house testing before committing to large orders, and verify that the supplier's HPLC method matches their own analytical protocol. For bulk purchases exceeding 100 grams, negotiate a quality agreement that includes retest rights and penalty clauses for out-of-specification material.

• Common Pitfalls: Incomplete documentation (missing MSDS or heavy metals report), ambiguous storage recommendations, and lack of third-party endotoxin testing.
• Selection Standards: Require HPLC chromatogram with peak area percentages, mass spectrum with molecular ion confirmation, and amino acid analysis report.
• Buyer Checklist: Verify supplier's ISO 9001 certification, request batch-specific COA, confirm shipping conditions (dry ice for international orders), and review stability data under recommended storage.

Core Product Advantages

The ll 37 peptide offered by our manufacturing facility delivers three distinct advantages that directly impact formulation success and cost efficiency. First, our proprietary synthesis process achieves >98% purity with less than 0.1% oxidation products, ensuring maximum bioactivity per milligram. Second, the lyophilized powder exhibits exceptional stability, maintaining >90% purity after 24 months at -20°C and surviving multiple freeze-thaw cycles without aggregation. Third, our competitive pricing model for bulk orders (starting at $45/gram for 10g MOQ) provides a cost-effective solution for formulators who require consistent quality without premium markups. Additionally, our technical support team offers formulation guidance, including recommended concentrations, pH adjustment protocols, and compatibility testing with common cosmetic ingredients.

Frequently Asked Questions

Q1: What is the minimum purity required for LL-37 peptide in cosmetic formulations?
For leave-on cosmetic products, a minimum purity of 95% by HPLC (detected at 214 nm) is recommended to ensure safety and efficacy. Lower purity grades may contain truncated sequences or oxidation byproducts that can cause skin irritation or reduce antimicrobial activity. Always request a COA with the specific HPLC chromatogram and peak purity data.

Q2: How should LL-37 peptide be stored and handled to maintain stability?
Lyophilized LL-37 peptide should be stored at -20°C in a desiccated environment, protected from light and moisture. Reconstituted solutions in sterile water or PBS must be aliquoted and stored at -80°C, with each aliquot used within 6 months. Avoid repeated freeze-thaw cycles, as they promote aggregation and loss of helical structure.

Q3: Can LL-37 peptide be used in combination with other active ingredients in cosmetic formulations?
Yes, LL-37 is compatible with most water-soluble actives, including hyaluronic acid, glycerin, and niacinamide. However, avoid co-formulation with strong chelating agents (e.g., EDTA at >0.1%) or high concentrations of ethanol (>5%), which can destabilize the peptide. Always conduct compatibility testing at the intended use concentration before scale-up.