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LL-37 dosage and protocol

Antimicrobial, antiviral peptide that serves as alternative to antibiotics with immune-boosting properties

  • Vial size: 5 mg
  • Reconstitution: 3 mL bacteriostatic water
  • Concentration: 1.67 mg/mL
  • Administration: subcutaneous

Research areas

  • Immunity
  • Antimicrobial
  • Wound Healing
  • Infection Fighting

Quick start

  • Reconstitute: Add 3 mL bacteriostatic water to the 5 mg vial for about 1.67 mg/mL
  • Typical dose: 100 mcg subcutaneous 2x daily for 1-6 weeks
  • Easy measuring: At 1.67 mg/mL, 1 unit is about 16.7 mcg on a U-100 syringe; 100 mcg is about 6 units (0.06 mL)
  • Storage: Freeze unreconstituted at -20°C; refrigerate at 2-8°C after mixing

Dosing protocol

PhaseDoseFrequencyVolume
Week 150 mcgOnce daily (SC)0.03 mL (3 units)
Week 2100 mcgOnce daily (SC)0.06 mL (6 units)
Week 3150 mcgOnce daily (SC)0.09 mL (9 units)
Week 4200 mcgOnce daily (SC)0.12 mL (12 units)
Weeks 5–8250–400 mcgOnce daily (SC)0.15–0.24 mL (15–24 units)

How it works

LL-37 is the only human member of the cathelicidin family of host-defense peptides. It is a 37-amino-acid, positively charged, amphipathic peptide cleaved from the precursor hCAP-18 and released by neutrophils and epithelial cells. Its direct antimicrobial action comes from binding negatively charged bacterial membranes and disrupting them; it also shows activity against some enveloped viruses and fungi and can interfere with biofilm formation in laboratory studies. Beyond killing microbes, LL-37 is a signaling molecule. It interacts with receptors such as FPR2, P2X7 and EGFR, recruiting immune cells, modulating cytokine release, neutralizing bacterial endotoxin, and promoting keratinocyte migration and new blood vessel formation, which links it to wound healing. Vitamin D drives its expression, which is part of why vitamin D status is studied in relation to infection risk. Evidence is mainly from cell and animal studies. A small human trial applied LL-37 topically to chronic venous leg ulcers with signals of improved healing, but there are no established clinical trials supporting systemic injection for infection. LL-37 is also double-edged: elevated levels are implicated in inflammatory skin diseases such as psoriasis and rosacea, and it can be toxic to human cells at higher concentrations.

Reconstitution steps

  • Draw 3.0 mL bacteriostatic water with a sterile syringe
  • Inject slowly down the vial wall; avoid foaming
  • Gently swirl/roll until dissolved (do not shake)
  • Label and refrigerate at 2–8°C, protected from light; use within 4 weeks

Storage

Store unreconstituted at -20°C. Refrigerate after mixing at 2-8°C

Important notes

  • Broad-spectrum defense against bacteria and viruses
  • Best taken during serious infections
  • 4-6 week cycles with evaluation of response
  • Can cause increased inflammation if overdosed
  • Risk of autoimmune activation at high levels
  • May damage sperm membranes
  • Work with doctor - high risk if misused
  • Start with TA-1 or TB-4 for safer immune support

Supplies

  • Bacteriostatic water (5mL)
  • Insulin syringes
  • Alcohol swabs

Related peptides

Calculate your LL-37 dose in syringe units

Crestigen is an educational research reference. Nothing here is medical advice; many of these compounds are not approved for human use. Talk to a licensed clinician before using any substance.