LL-37 (5 mg vial)

Protocol Overview

Concise summary of the regimen.

Dosing & Reconstitution

Frequency: Inject once daily subcutaneously. Some protocols use a 5-days-on, 2-days-off schedule. For 10 unit (0.10 mL) or smaller administrations during early titration, consider 30- or 50-unit insulin syringes for improved readability.

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 until dissolved (do not shake).
4. Label and refrigerate at 2 to 8 °C, protected from light. At 1.67 mg/mL, 1 unit = 0.01 mL » 16.7 mcg on a U-100 insulin syringe.

Storage Instructions

Proper storage preserves peptide quality.

• Lyophilized: store at -20 °C in dry, dark conditions; stable ~24 months.
• Reconstituted: refrigerate at 2 to 8 °C for up to 4 weeks; frozen at -20 °C for up to 6 months.
• Allow vials to reach room temperature before opening to reduce condensation uptake.

Supplies Needed

Plan based on an 8 to 16 week daily protocol with gradual titration.

Peptide Vials (LL-37, 5 mg each):

• 8 weeks: ~3 vials. 12 weeks: ~5 vials. 16 weeks: ~7 vials.

Insulin Syringes (U-100):

• Per week: 7 syringes (1/day).
• 8 weeks: 56. 12 weeks: 84. 16 weeks: 112.

Bacteriostatic Water (10 mL bottles):

• 8 weeks (3 vials): 1 bottle. 12 weeks (5 vials): 2 bottles. 16 weeks (7 vials): 3 bottles.

Alcohol Swabs:

• Per week: 14 swabs.
• 8 weeks: 112 (2 x 100-count). 16 weeks: 224 (3 x 100-count).

Important Notes

Practical considerations for consistency and safety.

• Use new sterile insulin syringes; dispose in a sharps container.
• Rotate injection sites (abdomen, thighs, upper arms) to reduce local irritation.
• Inject slowly; wait a few seconds before withdrawing the needle.
• Document daily dose and site rotation to maintain consistency.
• Early-phase doses (10 units or under) benefit from 30- or 50-unit syringes for precision.

How This Works

LL-37 exerts both direct and indirect antimicrobial effects. Its amphipathic, cationic a-helical structure (net +6 charge) allows it to preferentially bind and disrupt negatively charged microbial membranes. Beyond direct killing, LL-37 modulates host immunity: in murine sepsis models, it induced neutrophils to release microvesicles rich in antimicrobial proteins, lowering bacterial burden and improving survival. LL-37 can also bind bacterial lipopolysaccharide (LPS) and block its interaction with CD14/TLR4, reducing endotoxin-triggered TNF release and neutrophil apoptosis. These combined mechanisms help explain its potential in infection control and tissue-repair contexts.

Benefits & Side Effects

Observations from preclinical and clinical literature.

• In chronic venous leg ulcers (which often lack endogenous LL-37), topical treatment with synthetic LL-37

significantly accelerated healing rates compared to placebo.

• In diabetic foot ulcer trials, LL-37 cream improved granulation tissue formation and wound closure.
• Broad-spectrum antimicrobial action helps clear infections; in experimental sepsis models, LL-37

treatment reduced bacterial loads and mortality.

• Generally well tolerated; occasional mild injection-site reactions (redness, itch) may occur with

subcutaneous administration.

Lifestyle Factors

Complementary strategies for best outcomes.

• Optimize vitamin D status, as vitamin D upregulates endogenous cathelicidin/LL-37 expression.
• Support wound healing with adequate protein intake and micronutrient sufficiency (zinc, vitamin C).
• Maintain proper wound hygiene and dressing protocols if using for tissue-repair goals.
• Prioritize sleep and stress management to support immune function and recovery.

Injection Technique

General subcutaneous guidance from clinical best-practice resources.

1. Clean the vial stopper and skin with alcohol; allow to dry.
2. Pinch a skinfold; insert the needle at 45 to 90 degrees into subcutaneous tissue.
3. Do not aspirate for subcutaneous injections; inject slowly and steadily.
4. Wait 5 to 10 seconds before withdrawing; dispose of syringe in sharps container.
5. Rotate sites systematically (abdomen, thighs, upper arms) to avoid lipohypertrophy.

References

Source citations for further reading.

1. Evaluation of LL-37 in healing of hard-to-heal venous leg ulcers: multicentric RCT (Wound Repair and Regeneration).
2. Little peptide, big effects: the role of LL-37 in inflammation and autoimmune disease (Journal of Immunology).
3. Antimicrobial peptide LL-37 ameliorates a murine sepsis model via microvesicle release (Innate Immunity).
4. Efficacy of LL-37 cream in enhancing healing of diabetic foot ulcer: RCT (Archives of Dermatological Research).