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LL-37 (5 mg Vial) Dosage Protocol

Contents

Quickstart Highlights

LL‑37 (human cathelicidin) is a multifunctional host‑defense peptide with broad antimicrobial, immunomodulatory, and pro‑healing properties[1][2][3]. Clinical exploration has focused mainly on topical and intralesional use; a phase I melanoma study evaluated intratumoral injections with documented dermatologic changes and immune activation signals[6][7][8]. The subcutaneous framework below is a conservative, once‑daily microgram‑level layout to make syringe math clear; it is educational only and not a clinical dosing recommendation.

  • Reconstitute: Add 3.0 mL bacteriostatic water (max vial capacity) → ~1.67 mg/mL concentration.
  • Illustrative daily range: 100–250 mcg once daily with gradual titration (keeps volumes ≤0.15 mL per injection; well within typical SC comfort limits)[10].
  • Easy measuring: At 1.67 mg/mL, 1 unit = 0.01 mL ≈ 16.7 mcg on a U‑100 insulin syringe.
  • Storage: Lyophilized: freeze at −20 °C (−4 °F); after reconstitution, refrigerate at 2–8 °C (35.6–46.4 °F); avoid repeated freeze–thaw cycles[11][12].
LL-37 (5 mg Vial)
📘 Important: Before viewing any protocol, please consult our Prep & Injection Guide for essential preparation and safety instructions.

Dosing & Reconstitution Guide

Educational guide for reconstitution and daily dosing

Standard / Gradual Approach (3.0 mL = ~1.67 mg/mL)

Route/Frequency: Subcutaneous, once daily. Published human regimens have primarily used topical or intralesional LL‑37; a standardized subcutaneous systemic regimen has not been established[4][5][7].

Week Daily Dose Units (per injection) (mL)
Weeks 1–2 100 mcg (0.10 mg) 6 units (0.06 mL)
Weeks 3–4 150 mcg (0.15 mg) 9 units (0.09 mL)
Weeks 5–6 200 mcg (0.20 mg) 12 units (0.12 mL)
Weeks 7–12 250 mcg (0.25 mg) 15 units (0.15 mL)

Note: For ≤10‑unit (≤0.10 mL) administrations, consider 30‑ or 50‑unit insulin syringes for improved readability. Per‑injection volumes ≤0.15 mL are well below typical SC limits[10].

Reconstitution Steps

  1. Draw 3.0 mL bacteriostatic water with a sterile syringe.
  2. Inject slowly down the vial wall; avoid foaming.
  3. Gently swirl/roll until dissolved (do not shake).
  4. Label and refrigerate at 2–8 °C (35.6–46.4 °F), protected from light. Avoid repeated freeze–thaw cycles.[11][12]
Important: This guide is for therapeutic educational purposes only and does not constitute medical advice, diagnosis, or treatment. For research use only.

Supplies Needed

Plan based on an 8–16 week once‑daily framework with gradual titration.

  • Peptide Vials (LL‑37, 5 mg each):
    • 8 weeks ≈ 2 vials
    • 12 weeks ≈ 4 vials
    • 16 weeks ≈ 5 vials
  • Insulin Syringes (U‑100):
    • Per week: 7 syringes (1/day)
    • 8 weeks: 56 syringes
    • 12 weeks: 84 syringes
    • 16 weeks: 112 syringes
  • Bacteriostatic Water (10 mL bottles): Use ~3.0 mL per vial for reconstitution.
    • 8 weeks (2 vials): 6 mL → 1 × 10 mL bottle
    • 12 weeks (4 vials): 12 mL → 2 × 10 mL bottles
    • 16 weeks (5 vials): 15 mL → 2 × 10 mL bottles
  • Alcohol Swabs: One for the vial stopper + one for the injection site each day.
    • Per week: 14 swabs (2/day)
    • 8 weeks: 112 swabs → recommend 2 × 100‑count boxes
    • 12 weeks: 168 swabs → recommend 2 × 100‑count boxes
    • 16 weeks: 224 swabs → recommend 3 × 100‑count boxes
Peptide Vial
Insulin Syringes
Bacteriostatic Water
Alcohol Pads

Protocol Overview

Concise summary of the once‑daily framework.

  • Goal: Illustrate microgram‑level SC measurement for a host‑defense peptide with documented antimicrobial, angiogenic, and wound‑healing biology[1][2].
  • Schedule: Daily subcutaneous administration for 8–12 weeks (optional extension to 16 weeks); clinical LL‑37 studies to date are mainly topical or intralesional[4][5][7].
  • Dose Range (illustrative): 100–250 mcg once daily with gradual titration.
  • Reconstitution: 3.0 mL per 5 mg vial (~1.67 mg/mL) for clear unit conversions.
  • Storage: Lyophilized frozen; reconstituted refrigerated; avoid freeze–thaw cycles[11][12].

Dosing Protocol

Suggested conservative titration for measurement clarity.

  • Start: 100–150 mcg daily; increase by ~50 mcg every 1–2 weeks as tolerated.
  • Target: 200–250 mcg daily by Weeks 5–8.
  • Frequency: Once per day (subcutaneous).
  • Cycle Length: 8–12 weeks; optional extension to 16 weeks.
  • Timing: Choose a consistent time; rotate injection sites.

Storage Instructions

Proper storage preserves peptide quality.

  • Lyophilized: Store at −20 °C (−4 °F) in dry, dark conditions.
  • Reconstituted: Refrigerate at 2–8 °C (35.6–46.4 °F); aliquot if needed and avoid repeated freeze–thaw[11][12].
  • Allow vials to equilibrate to room temperature before opening to minimize condensation uptake and foaming during reconstitution[11].

Important Notes

Practical considerations and safety context.

  • Use a new sterile insulin syringe for each administration; dispose in a proper sharps container.
  • Rotate injection sites (abdomen, thighs, upper arms) to limit local irritation and lipohypertrophy[13].
  • Inject slowly; wait a few seconds before withdrawing the needle to ensure full dose delivery.
  • LL‑37 biology is context‑dependent; both pro‑healing and pro‑angiogenic or tumor‑promoting signals have been reported in specific models—interpret cautiously[8][15].

How This Works

LL‑37 links innate immunity and tissue repair. It exhibits direct antimicrobial effects (membrane disruption), immunomodulation (e.g., pDC and DC signaling), and pro‑angiogenic activity relevant to wound healing[1][2][3]. Human studies support topical LL‑37 in chronic wounds, while melanoma work has explored intratumoral injections with cutaneous reactions documented[4][5][6][7]. LL‑37–nucleic acid complexes can be immunostimulatory; prolonged or high local exposure has been associated with inflammatory dermatoses in experimental settings—underscoring cautious interpretation[14].

Potential Benefits & Side Effects

Highlights from preclinical and clinical literature.

  • Antimicrobial, anti‑biofilm, immunomodulatory, and angiogenic/tissue‑repair activities are reported across models[1][2][9].
  • Clinical wound literature indicates improved healing rates with topical LL‑37 formulations in venous and diabetic ulcers[4][5].
  • Potential risks include local injection‑site reactions and, context‑dependently, pro‑angiogenic or tumor‑promoting signals in certain tumor models; long‑term/high exposure has been linked to inflammatory skin changes in experimental studies[8][15][14].

Injection Technique

General subcutaneous guidance from reputable sources[10][12][13].

  • Clean the vial stopper and skin with alcohol; allow to dry.
  • Pinch a skinfold; insert the needle at 45–90° into subcutaneous tissue; do not aspirate[12].
  • Inject slowly and steadily; rotate sites systematically (abdomen, thighs, upper arms)[10][13].

Recommended Source

We recommend Prime Lab Peptides for high‑purity LL‑37 (5 mg).

Why Prime Lab Peptides?

  • High‑purity, third‑party‑tested lots with batch COAs.
  • Consistent, ISO‑aligned handling and documentation.
  • Reliable fulfillment to maintain cold‑chain integrity.

Important Note

This content is intended for therapeutic educational purposes only and does not constitute medical advice, diagnosis, or treatment.

References


  • Ridyard KE, Overhage J. Int J Mol Sci (2021)
    — The potential of human peptide LL‑37 as an antimicrobial and immunomodulatory agent (review).
    View Source

  • Koczulla R, et al. J Clin Invest (2003)
    — An angiogenic role for the human peptide antibiotic LL‑37/hCAP‑18 (host defense & wound neovascularization).
    View Source

  • Kahlenberg JM, Kaplan MJ. Nat Rev Rheumatol (2013)
    — Little peptide, big effects: LL‑37 in inflammation and autoimmunity (review).
    View Source

  • Grönberg A, et al. Wound Repair Regen (2014)
    — RCT: Topical LL‑37 enhanced healing of hard‑to‑heal venous leg ulcers.
    View Source

  • Miranda E, et al. Arch Dermatol Res (2023)
    — LL‑37 cream improved healing in diabetic foot ulcers (clinical study).
    View Source

  • Dolkar T, et al. J Cutan Pathol (2018)
    — Dermatologic findings during phase I intratumoral LL‑37 injections in melanoma.
    View Source

  • ClinicalTrials.gov
    — NCT02225366: Intratumoral injections of LL‑37 for melanoma (phase I schedule details).
    View Source

  • Lu F, et al. Front Pharmacol (2022)
    — Repurposing LL‑37 for cancer: dual pro/anti‑tumor context and delivery strategies (review).
    View Source

  • Xhindoli D, et al. Biochim Biophys Acta (2016)
    — Mechanistic overview: LL‑37 as a pore‑forming antimicrobial peptide.
    View Source

  • Usach I, et al. Adv Ther (2019)
    — Subcutaneous injection of drugs: factors and practical considerations (review).
    View Source

  • Wang W. J Pharm Sci (1999)
    — Instability, stabilization, and formulation of liquid protein pharmaceuticals (freeze–thaw considerations).
    View Source

  • Shi M, et al. Acta Pharm Sin B (2023)
    — Strategies to overcome protein/peptide instability; avoid repeated freeze–thaw cycles (review).
    View Source

  • CDC
    — Vaccine administration (SC route: site, angle, and technique) & You Call the Shots: Subcutaneous Injection.
    View Source
    View Source

  • Herster F, et al. Nat Commun (2020)
    — NET‑associated RNA and LL‑37 drive inflammatory responses (mechanistic caution).
    View Source

  • Ohuchi K, et al. Cancers (2023)
    — LL‑37 may promote local invasion of melanoma via pro‑angiogenic factors (context‑dependent risk).
    View Source