LL-37 dosing & administration
Human cathelicidin-derived antimicrobial peptide (37 amino acids) that disrupts bacterial membranes at MIC 0.62 μM against S. aureus, neutralizes endotoxin (LPS) to prevent septic shock, and has reached Phase II clinical trials as Ropocamptide for wound healing — achieving 6-fold accelerated healing at 0.5 mg/mL in venous leg ulcers
Written by Michael Carroll — Owner, Director of Research · Reviewed by the Peptide Initiative Research Team · Editorial standards
Dosing
How much do I take?
Topical: Applied onto the skin as a cream, gel, or lotion — it works mainly where you put it.
Bioavailability Local — acts mainly at the skin; little reaches the bloodstream.
2 documented dose levels — separate regimens, not a titration schedule
0.5 mg/mL gel
Frequency
Twice weekly
Duration
4 weeks
Lowest dose in the LL-37 (ropocamptide) Phase I/IIa venous leg-ulcer trial and the most effective: ~6-fold faster healing and ~68% ulcer-area reduction vs placebo, applied to the wound twice weekly [4].
1.6 mg/mL gel
Frequency
Twice weekly
Duration
4 weeks
Mid dose in the same trial; ~3-fold improvement and ~50% area reduction vs placebo. The highest tested concentration (3.2 mg/mL) showed no benefit over placebo, so dose escalation above this is not supported [4].
Timing
Best time to take
Apply LL-37 to clean, dry skin. For best results, use consistently at the same time(s) each day. Evening application is often preferred to allow overnight absorption, unless otherwise directed.
With food?
As a topical product, LL-37 is not affected by food intake. Apply to clean skin and allow adequate absorption time before covering the area.
If stacking
LL-37 should be used as directed by your healthcare provider. If combining with other medications or supplements, discuss potential interactions with your provider. Avoid combining with compounds that have overlapping mechanisms unless specifically guided by a medical professional.
Adjusting your dose
Increase if
- You've tolerated the current dose for the recommended period without significant side effects
- Therapeutic goals haven't been met at the current dose level
- Your healthcare provider recommends dose escalation based on your response
- Lab work or clinical assessments support a higher dose
Decrease if
- Side effects are bothersome or impacting daily life despite management strategies
- You experience any signs of an adverse reaction
- Lab results indicate the need for dose reduction
- Your healthcare provider recommends a lower dose based on your response
Signs of right dose
- Therapeutic goals being met with minimal side effects
- Stable and consistent response to treatment
- Lab values or clinical markers trending in the right direction
- Good tolerance with manageable or absent side effects
Administration
How do I use it?
Reconstitution
What you need
Injection
Route
LL-37 is administered Topical application (wound healing)—no injection required
Best sites
Storage
Before reconstitution
Store LL-37 in the refrigerator at 36-46°F (2-8°C) in its original packaging. Protect from light and moisture. Do not freeze. Check the expiration date before use. Some formulations may be stored at room temperature for limited periods—check your specific product labeling.
After reconstitution
Once reconstituted, LL-37 should be kept refrigerated at 36-46°F (2-8°C) and used within the timeframe specified on your product labeling (typically 14-28 days). Label the vial with the reconstitution date. Do not use if the solution appears cloudy, discolored, or contains particles.
Signs of degradation — discard the vial
Sample daily schedule
As prescribed (once daily)
As prescribed by your healthcare provider injection
Site: Topical application (wound healing)—rotate sites if applicable
Maintain a consistent schedule for optimal results with LL-37. Set reminders if needed. If you miss a dose, follow your healthcare provider's instructions—do not double up on doses to compensate.
Safety
Is it safe?
Side effects
Commonly reported: Local site irritation, Transient stinging or burning, Mild perilesional erythema, Increased wound exudate
Less common: Allergic contact reaction
Stop and seek help if
- Severe or worsening side effects that don't improve with dose adjustment or supportive care
- Signs of an allergic reaction—rash, hives, swelling, or difficulty breathing
- Your healthcare provider recommends discontinuation based on your clinical response
- Development of any new medical condition that may be contraindicated with LL-37
- Pregnancy or planning to become pregnant (unless specifically approved for use during pregnancy)
- Abnormal lab results or clinical markers that suggest adverse effects
LL-37 should only be started, adjusted, or discontinued under medical supervision. This information is for educational purposes only and does not replace professional medical advice. Never stop a prescribed treatment without consulting your healthcare provider first, as abrupt discontinuation may have consequences.
Flagged pairings
- High-concentration saline solutions — elevated salt concentrations can reduce LL-37 antimicrobial activity through charge shielding effects — Use with caution—discuss with your healthcare provider.
- Anionic surfactants or dressings — may bind and inactivate the cationic LL-37 peptide through electrostatic complexation — Use with caution—discuss with your healthcare provider.
- Serum-rich wound environments without dose adjustment — serum proteins can partially sequester LL-37 and reduce effective concentration — Use with caution—discuss with your healthcare provider.
Published research
What the studies show
Taylor RM, Whitehouse CJ, Caldecott KW · 2000
DNA ligase III's zinc finger enables it to identify and repair DNA breaks at sites of clustered damage, particularly important for radiation-induced injury recovery.
Dürr UH, Sudheendra US, Ramamoorthy A · 2006
Research (2006) demonstrates ll 37's potent antimicrobial activity and broad-spectrum effectiveness against pathogenic microorganisms.
Turner J, Cho Y, Dinh NN, et al. · 1998
Research (1996) demonstrates ll 37's potent antimicrobial activity and broad-spectrum effectiveness against pathogenic microorganisms.
Grönberg A, Mahlapuu M, Ståhle M, Whately-Smith C, Rollman O · 2014
Clinical trial (2014) provides evidence for ll 37's effectiveness in therapeutic management.
Ridyard KE, Overhage J · 2021
Research (2021) on ll 37 contributes important scientific knowledge about its biological and pharmacological properties.
Studied for
Conditions LL-37 has been researched in
Want the full picture?
The complete LL-37 research profile: mechanism of action, clinical studies, effectiveness timeline, and FAQ.