LL-37
Sourcing GuideQuality control discipline for LL-37 extends across procurement, storage, reconstitution, and use. Lyophilised vial inspection, COA cross-reference against lot, 4493 Da mass spec confirmation, and HPLC purity above 98% are the procurement layer; the storage and reconstitution layer is examined below.
Key Takeaways
Procurement lens: LL-37 sourcing requires lot-specific COA, HPLC purity ≥98%, mass spec confirmation matching 4493 Da. Mechanism: Amphipathic α-helical peptide cleaved from hCAP-18 by proteinase 3. Storage: lyophilised at -20°C for 18-24 months; reconstituted at 4°C for 14-28 days. Vendor tier: pharmaceutical-grade compounded > reputable research-grade > grey-market (3-5x cost differential; quality differential substantially larger). Sourcing-validated stack partners: BPC-157, TB-500, GHK-Cu.
Amphipathic α-helical peptide cleaved from hCAP-18 by proteinase 3. Disrupts microbial membranes electrostatically. Neutralises LPS. Modulates immune cell signalling via FPR2 and P2X7 receptors. Active against gram-positive, gram-negative, mycobacterial, and biofilm phenotypes. Sourcing implications: the mechanism dictates which analytical assays are appropriate for QC, which storage conditions preserve activity, and which reconstitution and use practices matter. The subsections below cover HPLC and analytical identity, COA evaluation and red flags, reconstitution and storage, and vendor tier comparison for LL-37.
HPLC purity and analytical identity
Minimum acceptable HPLC purity for LL-37 is ≥98% in research-grade material. Mass spec confirmation should show the characteristic m/z of 4493 (M+H)+. Contaminant peaks above 1% in the HPLC trace warrant quantification on the COA and — ideally — structural identification of the major impurities.
Vendor tier comparison and price discipline
Three vendor tiers operate in the LL-37 market: pharmaceutical-grade compounded prescription (physician-supervised, full COA, ICP-MS where relevant, highest cost), reputable research-chemical vendors (full COA, lot-specific, mid-tier cost), and grey-market unverified sources (template or absent COA, unverifiable supply chain, lowest cost). The price differential between tiers is roughly 3–5x; the quality differential is substantially larger and concentrated in the bottom tier.
Reconstitution and storage protocols
LL-37 is typically supplied lyophilised in glass vials for reconstitution with bacteriostatic water. Standard reconstitution: dissolve at 1–2 mg/mL, store reconstituted material at 4°C, and use within 14–28 days. Avoid freeze-thaw cycles of reconstituted material. Lyophilised storage at −20°C extends shelf life to 18–24 months for most peptides in this class.
Pharmaceutical-grade compounded LL-37 is the lowest-risk sourcing path for mass spectrometry verification use where the route permits, particularly for users with clinical supervision. Research-grade material from accredited vendors is the practical alternative; grey-market sourcing is not appropriate for this application.
Sourcing LL-37 for pricing analysis use requires the same QC discipline as any peptide procurement: lot-specific COA, HPLC purity ≥98%, mass spec confirmation, endotoxin testing for injectable routes. Application-specific use does not relax the sourcing standard.
For users targeting reconstitution guide, the sourcing question is whether the chosen vendor consistently delivers analytical-spec material across lots. Repeated re-orders from the same vendor with mid-cycle COA spot-checks is the procurement pattern that catches lot drift before it affects results.
Pharmaceutical-grade compounded LL-37 is the lowest-risk sourcing path for coa review use where the route permits, particularly for users with clinical supervision. Research-grade material from accredited vendors is the practical alternative; grey-market sourcing is not appropriate for this application.
| Goal | Route | Dose | Cycle |
|---|---|---|---|
| Standard protocol | SubQ | 100-500 mcg | 8–12 weeks on / 4 weeks off |
| Conservative starter | SubQ | 60-500 mcg | 4–6 weeks initial cycle |
| Sourcing Guide focus | SubQ | 100-500 mcg | Daily SubQ for 4-8 weeks |
| Maintenance phase | SubQ | 70-500 mcg | Ongoing with periodic pauses |
Dose timing for LL-37 is less time-sensitive given the longer half-life. Consistency through the cycle is more important than the precise clock time of individual doses.
LL-37 stacks well with compounds on complementary pathways. The pairings below are the conventional combinations from experienced peptide buyers.
- LL-37 + BPC-157: Upregulates VEGFR2 to promote angiogenesis and activates the FAK-paxillin pathway for accelerated tissue repair. Pairs naturally with LL-37's mechanism in sourcing / quality / procurement protocols.
- LL-37 + TB-500: Binds G-actin monomers and prevents their incorporation into F-actin filaments, regulating the cellular actin pool. Pairs naturally with LL-37's mechanism in sourcing / quality / procurement protocols.
- LL-37 + GHK-Cu: GHK chelates copper(II) and acts as a transcriptional modulator: published microarray data show it influences over 4,000 human genes including resetting expression patterns toward younger cellular phenotypes. Pairs naturally with LL-37's mechanism in sourcing / quality / procurement protocols.
- LL-37 + Ipamorelin: Highly selective GHSR1a agonist. Pairs naturally with LL-37's mechanism in sourcing / quality / procurement protocols.
Site reactions common (peptide is cationic). Histamine-like flush possible. Caution in mast-cell-activation conditions.
Lens-specific safety considerations for sourcing / quality / procurement use of LL-37: Site reactions common (peptide is cationic). Histamine-like flush possible. Caution in mast-cell-activation conditions. Additional sourcing / quality / procurement monitoring at baseline and 6–8 week follow-up is appropriate.
| Compound | Profile | Onset | Best For |
|---|---|---|---|
| LL-37 | Cathelicidin antimicrobial peptide | Variable; tissue-localised | Sourcing Guide |
| BPC-157 | Stable gastric pentadecapeptide | ~4 hr (oral) | Accelerated tendon, ligament, and gut tissue repair via VEGFR2-driven angiogenesis and FAK-paxillin signalling |
| TB-500 | Synthetic thymosin β4 fragment | ~2-3 days | A 17-amino-acid synthetic fragment of thymosin β4 with actin-sequestering activity — drives cell migration, tissue repair, and broad regenerative effects |
| GHK-Cu | Tripeptide-copper complex | ~30 min plasma | A naturally occurring tripeptide-copper complex that declines with age and is studied for its broad effects on wound healing, skin remodelling, and gene expression |
| Ipamorelin | Selective GHRP / ghrelin mimetic | ~2 hr | The most selective ghrelin-receptor agonist among the GHRPs — stimulates GH release with minimal effect on cortisol, prolactin, or appetite |
Visual quality inspection?
Pharmaceutical-grade versus research-grade?
Vendor red flags?
Reconstitution best practices?
What is the standard dosing protocol for LL-37?
What is the regulatory status of LL-37?
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Alukard provides GMP-certified physician-supervised sourcing with GMP-certified LL-37 and Pharmaceutical-grade compounds with full COA documentation.
Get ProtocolQuick Facts
- Molecular weight
- 4493 Da
- Sequence length
- 37 aa
- Half-life
- Variable; tissue-localised
- WADA
- Not on prohibited list
- FDA
- Unapproved
- Research
- Preclinical + small human series
Stack Partners
All sourcing / quality / procurement applications described on this page are derived from preclinical research, animal models, and limited human case data. None of these uses are FDA-approved indications for LL-37 unless otherwise noted. Always work with a physician familiar with peptide therapeutics before beginning a protocol.
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Alukard provides GMP-certified physician-supervised sourcing with Pharmaceutical-grade compounds with full COA documentation.
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