Educational guide
LL-37 Dosing, Need to Know Information, Safety, Stacks, Dosing Calculator and more!
How much do I take? Is this right for me? How do I use it? Is it safe? How do I know it's working? Compound Profile Scientific & Efficacy Data C205H340N60O53 Molecular Formula 4,493.26 Da Molecular Weight Short systemic half-life (minutes) due to protease susc
This guide cannot diagnose a condition or recommend a personal treatment plan. Discuss medical questions with a qualified professional.
How much do I take?
Is this right for me?
How do I use it?
Is it safe?
How do I know it's working?
Compound Profile
Scientific & Efficacy Data
C205H340N60O53
Molecular Formula
4,493.26 Da
Molecular Weight
Short systemic half-life (minutes) due to protease susceptibility; local tissue persistence at wound sites is longer due to binding to extracellular matrix components and lipid membranes
Half-Life
Topical application achieves high local wound-bed concentrations; systemic bioavailability limited by rapid proteolytic degradation and serum protein binding; not intended for oral delivery
Bioavailability
154947-66-7
CAS #
16198951
PubChem ID ↗
Developed By · 1995-1996 (initial identification and characterization); 2014 (Phase I/IIa clinical trial); clinical development ongoing
Endogenous; developed by Prokera Biologics
Prokera Biologics / OncolyticsBiotech
Primary Benefits
Clinical trials show this peptide heals stubborn wounds six times faster than placebo by boosting new blood vessel growth and tissue repair.
Works like a natural antibiotic in your body, punching holes in harmful bacteria including drug-resistant strains that normal antibiotics can't kill.
Calls your immune cells to action like a chemical alarm, helping your body mount a stronger defense against bacteria, fungi, and viruses.
Amino Acid Sequence
Dosing
How muchdo 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.
Starting Dose
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].
Standard Dose
1.6 mg/mL gel
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
Dosing Calculator
Calculate Your Exact Dose
Step 1: Peptide Weight
Find the weight printed on your peptide vial label
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The peptide weight is printed on the label
The weight is on the label
Select Weight
Look for a number followed by 'mg' on the vial label (e.g., 5mg, 10mg)
Suitability
Is thisright for me?
Best For
Treatment of chronic non-healing wounds including venous leg ulcers and diabetic ulcers
LL-37 is particularly well-suited for individuals focused on treatment of chronic non-healing wounds including venous leg ulcers and diabetic ulcers. Research and clinical experience suggest meaningful benefits in this area when used as part of a comprehensive treatment approach.
Immune defense against antibiotic-resistant bacterial infections (MRSA, Pseudomonas)
LL-37 is particularly well-suited for individuals focused on immune defense against antibiotic-resistant bacterial infections (mrsa, pseudomonas). Research and clinical experience suggest meaningful benefits in this area when used as part of a comprehensive treatment approach.
Anti-biofilm strategies for chronic wound infections and medical device-associated infections
LL-37 is particularly well-suited for individuals focused on anti-biofilm strategies for chronic wound infections and medical device-associated infections. Research and clinical experience suggest meaningful benefits in this area when used as part of a comprehensive treatment approach.
Boosting innate immune defense in immunocompromised or aging individuals
LL-37 is particularly well-suited for individuals focused on boosting innate immune defense in immunocompromised or aging individuals. Research and clinical experience suggest meaningful benefits in this area when used as part of a comprehensive treatment approach.
Consider Alternatives If
Goal: Alternative approaches for immune support
Consider: Consult your healthcare provider for alternatives to LL-37 based on your specific needs and medical history
Goal: Alternative immune-modulating peptides
Consider: Thymosin Alpha-1, LL-37, Thymulin
Goal: Non-peptide immune support
Consider: Vitamin D3, Zinc supplementation, Beta-glucans
Who Should Avoid
Do not use if
×Known hypersensitivity to cathelicidin peptides or formulation components
×Active hemolytic conditions — LL-37 demonstrates concentration-dependent hemolytic activity
×Pregnancy and breastfeeding — insufficient reproductive safety data from clinical trials
×Severe renal impairment — peptide clearance may be altered
Use with caution if
!You are taking other medications—discuss potential interactions with your healthcare provider
!You have a history of liver or kidney disease
!You are elderly or have multiple medical conditions
!You are planning surgery in the near future—inform your surgeon about LL-37 use
!You have any chronic health conditions that require regular monitoring
Not Sure?
Compare LL-37 with similar peptides to find the best fit for your goals.
Administration
How do Iuse it?
Reconstitution
What you need
•LL-37 in its prescribed form
•Clean, dry storage container
•Measuring device if applicable (oral syringe, measuring cup)
•Calendar or reminder app for dosing schedule
Example
LL-37 comes in pre-measured doses or forms. Follow the exact dosing instructions on your prescription label. No reconstitution or mixing is typically required for this formulation.
Use LL-37 exactly as prescribed. Each unit contains the labeled amount. Your healthcare provider will determine the appropriate dose based on your individual needs and response.
Injection
Route
LL-37 is administered Topical application (wound healing)—no injection required
Best sites
•Not applicable—this is not an injectable formulation
Technique
1.Follow the specific administration instructions for your LL-37 formulation
2.Take or apply as directed by your healthcare provider
3.Store properly between uses according to package instructions
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
Solution appears cloudy, discolored, or contains visible particles (should be clear)
Product has been exposed to temperatures outside the recommended storage range
Product has been frozen (unless specifically designed for freeze-thaw stability)
Expiration date has passed or reconstituted solution has exceeded its use-by date
Unusual odor, color change, or visible contamination
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 itsafe?
Safety Profile
LL-37 is an endogenous cathelicidin antimicrobial peptide naturally produced by immune cells and epithelial tissues, conferring inherent biocompatibility and low toxicity at physiological concentrations. Synthetic LL-37 shows excellent safety in in vitro immune assays and animal models with no hepatotoxicity, nephrotoxicity, or genotoxicity at relevant doses. At elevated concentrations, the cationic amphipathic structure can cause hemolysis and cell membrane damage, but therapeutic doses are far below these thresholds. Injection site reactions are minimal in research applications.
LL-37 safety derives from extensive basic research in immunology and dermatology journals (Nature Immunology, Journal of Immunology) demonstrating antimicrobial activity, wound healing promotion, and immune modulation without systemic toxicity. Human clinical data are limited—most applications remain in vitro or preclinical. Phase 1 safety and pharmacokinetics data suggest good tolerability, but Phase 2+ efficacy trials in infectious disease and skin conditions are ongoing. The peptide is generally recognized as safe for topical and research applications.
Common Side Effects
Experienced by some users
Local site irritation
Mild redness, warmth, or irritation at the wound application site. This is the most frequently reported adverse effect in clinical trials and reflects the peptide's interaction with wound-bed tissues.
Management: Generally self-limiting. If irritation is significant, reduce application frequency to every other day. Ensure wound is gently cleansed before application.
Transient stinging or burning
Brief stinging or burning sensation upon application to open wound surfaces, typically lasting seconds to minutes.
Management: Allow reconstituted solution to reach room temperature before application. Sensation typically diminishes with subsequent applications as wound healing progresses.
Mild perilesional erythema
Redness in the skin surrounding the treated wound area, reflecting local immune activation and increased blood flow from LL-37-induced angiogenesis.
Management: Usually indicates active healing response. Monitor for signs of infection versus expected inflammatory healing. Should remain localized and non-spreading.
Increased wound exudate
Temporary increase in wound fluid production during initial treatment phase as antimicrobial and pro-healing mechanisms activate.
Management: Use appropriate absorbent wound dressings. Typically normalizes within 1-2 weeks as healing progresses and bacterial bioburden is reduced.
Less Common
•Allergic contact reaction
These typically resolve with continued use or dose adjustment.
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.
Interactions
With other peptides
✓May be used together under medical guidance.
With medications
!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.
With supplements
✓Multivitamins - Generally safe to take alongside LL-37. Space doses apart if taking oral formulations to ensure optimal absorption.
✓Electrolyte supplements - Helpful if experiencing any GI side effects that could lead to dehydration. Safe to combine.
Effectiveness
Does itwork?
Evidence Level
Moderate human trials
What to Expect
Days 1-7
What you might notice
•Reduction in wound bioburden and bacterial colonization from direct antimicrobial activity
•Initial wound bed preparation with cleaner, healthier-appearing granulation tissue
•Possible mild local irritation or stinging upon application that improves with repeated use
•Early recruitment of immune cells to wound site through FPRL1-mediated chemotaxis
What's normal
•The antimicrobial effect begins immediately upon contact with wound bed
•Increased wound exudate is common during the first week as bacterial killing and immune activation occur
•Visible wound changes may be subtle initially — the peptide is establishing conditions for healing
What's next
→Continue daily application as tolerated
→Expect wound bed to transition from inflammatory to proliferative phase
→Take baseline wound measurements and photographs for tracking progress
Week 2-4
•Visible wound size reduction and epithelial advancement from wound edges
•Improved granulation tissue quality with increased vascularity (LL-37-induced angiogenesis)
•Reduced wound odor and signs of bacterial infection
•In the Phase I/IIa trial, the 0.5 mg/mL group showed 6-fold accelerated healing at this timepoint
•Progressive wound contraction and re-epithelialization are expected
•Some wounds heal faster than others depending on underlying conditions (venous insufficiency, diabetes)
•Periwound erythema should be stable or decreasing — increasing redness may indicate infection
→Continue treatment until wound closure or per clinical protocol (typically 4-12 weeks)
→Document weekly wound measurements to track healing trajectory
→Assess whether to continue current concentration or adjust based on response
Week 4-12
•Continued wound closure with re-epithelialization and scar maturation
•Significant reduction or complete elimination of chronic wound biofilm
•Wound may reach complete closure during this period for many patients
•Stable, healthy wound bed without signs of recurrent infection
•Healing rates vary — some chronic wounds may require the full 12-week course
•The anti-biofilm effects help prevent the recurrent infections common in chronic wounds
•Newly healed tissue may appear pink or slightly different from surrounding skin
→Upon wound closure, discontinue LL-37 application
→Maintain standard wound care and compression therapy if applicable
→Monitor for wound recurrence at follow-up visits
Signs It's Working
Treatment Response
✓Improvement in the primary symptoms or condition being treated
✓Positive changes in relevant lab values or clinical markers
✓Consistent, stable response to LL-37 over time
✓Reduction in symptom frequency or severity
General Well-being
✓Improved energy levels and daily functioning
✓Better quality of life related to the treated condition
✓Manageable or absent side effects indicating good tolerance
✓Positive feedback from healthcare provider during check-ups
Not Seeing Results?
Common reasons
•Not at therapeutic dose yet—initial doses are for building tolerance, not maximum effect
•Insufficient time at target dose—most compounds need several weeks to show full benefits
•Inconsistent dosing schedule—regular, consistent use is crucial for optimal results
•Individual variation in response—genetics, metabolism, and other factors affect outcomes
•Underlying conditions or medications interfering with absorption or effectiveness
•Improper storage leading to degraded product—always verify proper storage conditions
Key Research
[1]"The human antimicrobial and chemotactic peptides LL-37 and alpha-defensins are expressed by specific lymphocyte and monocyte populations"
Agerberth B, Charo J, Werr J, Olsson B, Idali F, Lindbom L, Kiessling R, Jörnvall H, Wigzell H, Gudmundsson GH, 2000
Finding: 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.
[2]"LL-37, the only human member of the cathelicidin family of antimicrobial peptides"
Dürr UH, Sudheendra US, Ramamoorthy A, 2006
Finding: Research (2006) demonstrates ll 37's potent antimicrobial activity and broad-spectrum effectiveness against pathogenic microorganisms.
[3]"The human cationic antimicrobial protein (hCAP-18) is expressed in the bone marrow of human neonates and in bone marrow transplant recipients"
Gudmundsson GH, Agerberth B, Odeberg J, Bergman T, Olsson B, Salcedo R, 1996
Finding: Research (1996) demonstrates ll 37's potent antimicrobial activity and broad-spectrum effectiveness against pathogenic microorganisms.
[4]"Treatment of hard-to-heal venous leg ulcers with LL-37 (Ropocamptide): A Phase I/IIa clinical trial"
Grönberg A, Mahlapuu M, Ståhle M, Whately-Smith C, Rollman O, 2014
Finding: Clinical trial (2014) provides evidence for ll 37's effectiveness in therapeutic management.
[5]"LL-37-derived peptides eradicate multidrug-resistant Staphylococcus aureus from thermally wounded human skin equivalents"
Ridyard KE, Overhage J, 2021
Finding: Research (2021) on ll 37 contributes important scientific knowledge about its biological and pharmacological properties.
Organ Targets
Powered by Human Organ Atlas
Organs and body systems affected by LL-37, mapped to the Human Organ Atlas — an open-access 3D portal featuring 56 organs imaged at near-cellular resolution.
Lungs
Respiratory System
Antimicrobial defense peptide active in pulmonary mucosal immunity
Stomach & GI Tract
Digestive System
Supports intestinal barrier defense and modulates gut immune response
The Science
Stacking & Combinations
Frequently Asked Questions