PeppiLibrary

Immune

LL-37 peptide reference

Endogenous antimicrobial peptide. Broad-spectrum antibacterial, antiviral, immunomodulatory.

Last reviewed May 6, 2026 Human data Not FDA approved
Peppi reviewing LL-37 notes
Default dose label1 mg
Preferred routeSubQ (systemic) / Topical (localised infection)
Frequency label1× daily during acute course
Storage window14 days mixed

Evidence snapshot

Human data

Evidence maturityHuman data
Extensive in-vitro and animal data; limited human clinical use

Research chemical

Route map

How records are usually labeled

1 SubQ
2 Topical

Rotate subQ sites.

Vial timeline

Storage cues to log

Before mixRefrigerate 2–8 °C; freeze long-term.
After mixRefrigerate 2–8 °C, use within 14 days; LL-37 is more proteolysis-prone than many peptides.
Use-by cue14 days after mixing
Mixed vial window14 days
Use this as a record-keeping cue, not a replacement for product labeling.

Peppi workflow

From vial to review

Vial 5 mg vial
Dose 1 mg
Route SubQ (systemic) / Topical (localised infection)
Review 14d storage

Peppi turns scattered dose, vial, route, storage, note, and report details into one record trail.

Educational reference only

This page helps you understand what to track for LL-37. It is not medical advice, a prescription, or a recommendation to use this peptide. Discuss dose, route, timing, storage, and safety with a qualified healthcare professional.

Overview

LL-37 is a 37-amino-acid cationic antimicrobial peptide derived from the cathelicidin precursor hCAP-18. It is the only human cathelicidin and serves as a frontline innate-immunity defender against bacteria, viruses, and fungi. Beyond direct microbicidal activity, it modulates inflammation, wound healing, and chemotaxis. Researched for chronic infections, biofilms, and inflammatory skin disorders.

Also known as: Cathelicidin LL-37, hCAP-18.

Antibiotic-resistant infection researchBiofilm disruption researchWound healing adjunctChronic Lyme protocols (off-label, controversial)

Mechanism and timing snapshot

Cationic amphipathic α-helix that disrupts bacterial membranes. Also modulates host immune responses via formyl peptide receptors and toll-like receptor pathways. Synergises with other antimicrobial peptides.

Onset label30 min
Catalog onset field, when available.
Half-life label30 min
Plasma half-life short (~30 min); locally active longer in tissue
Duration label4 hr
Catalog duration field, when available.
subQ Moderate (susceptible to proteolysis)
topical Moderate (locally active)
oral Negligible

Tracking defaults

These values come from Peppi's catalog so records can be prefilled consistently. They should be reviewed against your clinician's instructions before logging real-world use.

Catalog default dose1 mg
Catalog dose range500 mcg - 5 mg
Default routeSubQ
Frequency label1× daily during acute course
Best time labelAnytime during acute use.
Food noteNone.

Catalog protocol note

500–1000 mcg subQ daily for 7–14 days; or topical for skin indications.

Routes and site notes

Available route labelsSubQ, Topical
Preferred route labelSubQ (systemic) / Topical (localised infection)
Common site labelsAbdomen, Topical application to lesion
Site rotation noteRotate subQ sites.

Chemistry

SequenceLLGDFFRKSKEKIGKEFKRIVQRIKDFLRNLVPRTES
Amino acids37
Molecular formulaC205H340N60O53
Molecular weight4493.33 Da

Vial, reconstitution, and storage

Supply formLyophilized powder
Typical vial size5 mg
DiluentBacteriostatic water (some sources recommend acetic acid 0.6% for stability)
Diluent volume2.5 mL
Concentration note5 mg in 2.5 mL → 0.50 mL = 1 mg (50 units on a 100-unit insulin syringe).
Before reconstitutionRefrigerate 2–8 °C; freeze long-term.
After reconstitutionRefrigerate 2–8 °C, use within 14 days; LL-37 is more proteolysis-prone than many peptides.
Reconstituted shelf life14 days
Light sensitiveYes
Freeze/thaw warningYes

Safety notes

Common and rare side effects listed in the catalog

  • Injection-site reactions
  • Possible mild flu-like response
  • Pro-inflammatory effects at high doses
  • Allergic reaction

Contraindications and warnings

  • Severe rosacea (LL-37 implicated in pathology)
  • Active autoimmune skin disorders
  • Not FDA-approved.
  • Pro-inflammatory at supraphysiologic doses — do not over-dose seeking faster effect.

Other considerations

  • Endogenous LL-37 is dysregulated in rosacea — exogenous administration is contraindicated there.
  • Short courses preferred — chronic use for general 'wellness' is not well-characterised.

Evidence and regulatory context

Evidence levelExtensive in-vitro and animal data; limited human clinical use
FDA approvedNo
Regulatory statusResearch chemical
Prescription requiredNo
Approved countriesNot listed

Stacking and cycle notes

Stacks well withthymosin-alpha-1
Avoid combining noteNot listed
Typical cycle label1–2
Typical break label2+
Cycle guidanceAcute infection-fighting courses, not chronic supplementation.

Tracking tips

  • Short courses for acute concerns — not a daily wellness peptide.
  • Avoid if you have rosacea — LL-37 is implicated in disease pathology.
  • Pairs with Thymosin Alpha-1 in immune-stack research protocols.

References

Track it in Peppi

Keep LL-37 records organized.

Use Peppi for dose logs, vial inventory, storage dates, reminders, journal notes, photos, and clinician-ready reports.

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FAQ

What should I track for LL-37?

Track the peptide name, dose amount and unit, route, vial label, timing, reconstitution or expiration dates, storage notes, and any symptoms or questions for clinician review.

Does Peppi tell me how to use LL-37?

No. Peppi organizes educational reference and your own records. Protocol decisions should come from a qualified healthcare professional.

Can I export LL-37 records?

Peppi is designed to keep dose logs, vial inventory, journal notes, and reports easier to review and export.

Last reviewed: May 6, 2026