Pepbase

LL-37

Also known as: Cathelicidin, CAP18

Not FDA Approved
Immune SupportWeight LossHealthAnti-Aging

Primary use: Immune support and infection control

ℹ️

What is LL-37?

LL-37 is the only human cathelicidin antimicrobial peptide, derived from hCAP18, with significant antimicrobial and immune modulatory properties. It is used primarily for its wound healing and broad-spectrum antimicrobial activities, including action against antibiotic-resistant bacteria. While it shows promising results in clinical trials for chronic wound healing, it is not yet FDA-approved, and users should be cautious of potential toxicity and inflammatory side effects.

Primary Benefits
  • Broad-spectrum antimicrobial activity
  • Promotes wound healing
  • Reduces inflammation
How It Works

LL-37 disrupts microbial cell membranes and modulates immune responses by promoting immune cell migration. Its cationic nature allows it to bind to bacterial membranes, forming pores that lead to cell death, while also engaging in immune signaling pathways to enhance wound healing and reduce inflammation.

⚠️

Safety Tips

Precautions reported in community discussions and literature. This is not a complete list. View Full Side Effects Guide →
  • 1DON'T start with high doses; begin with the lowest effective dose.
  • 2DON'T use if you have a history of autoimmune conditions without medical advice.
  • 3DON'T apply or inject on unclean skin to avoid contamination.
  • 4DON'T exceed recommended durations to prevent toxicity.
  • 5NEVER use homemade formulations due to sterility risks.
  • 6DON'T use concurrently with substances causing hypersensitivity to peptides.
  • 7AVOID using LL-37 without medical supervision if pregnant or breastfeeding.
  • 8DON'T store above recommended temperatures to maintain stability.
  • 9DON'T mix LL-37 with non-sterile solutions.

Who Should NOT Use

  • Autoimmune disease history
  • Hypersensitivity to peptides
  • Pregnancy and breastfeeding

Dosage & Protocols

Different purposes have different protocols, dosing, and considerations

💉

Chronic wound healing

moderate evidence

Investigated for wound healing and antimicrobial activity against infections resistant to antibiotics. Used in clinical trials for chronic venous ulcers and skin conditions.

Evidence: Clinical trials have shown LL-37 accelerates wound healing and reduces bacterial presence on wound surfaces.

The following are ranges reported in published literature and community discussions. These are NOT recommendations or medical advice.

Range
100-200 mcg
Frequency
once daily
Cycle
2-8 weeks
Route
Subcutaneous, Intramuscular
TimingMorning
NotesDosage should be adjusted based on the severity of infection and wound state.

📋Community-Reported Protocols

Not recommendations:

The following protocols are compiled from online communities and published literature. Pepbase does not endorse, recommend, or verify these protocols. They are provided for informational purposes only. Individual responses vary significantly. Consult a licensed medical professional before any use.

Reported GoalReported DoseReported FrequencyReported Route
Wound healing0.5 mg/mLtwice weeklyTopical gel application

⏱️Pharmacokinetics

Half-Life
30 min
Time to Peak
30 min
Clearance
2.5 hrs

⚡Reported Side Effects

This is not a complete list. Other side effects may occur.

Common
Injection site reactionsvery common (>10%)
Skin toxicity (ulcers, burning)common (1-10%)
Allergic reactionsreported (frequency unknown)
Serious / Rare
  • • High-dose toxicity concerns
Injection-Specific Warnings
  • Sterile technique is essential to avoid contamination.

🧊Storage

Temperature
2-8°C
Reconstituted
Use within expiration
Shelf Life
6 months
Light Sensitive
Yes - protect from light
💉

Antimicrobial therapy

moderate evidence

Used for its broad-spectrum activity against bacteria, viruses, and fungi in investigational research settings. Particularly considered as an alternative to conventional antibiotics.

Evidence: Research indicates LL-37 is effective against a wide range of pathogens and biofilm-related infections.

The following are ranges reported in published literature and community discussions. These are NOT recommendations or medical advice.

Range
50-300 mcg
Frequency
once daily
Cycle
2-8 weeks
Route
Subcutaneous
TimingMorning
NotesAdjust dose based on pathogen type and infection severity.

📋Community-Reported Protocols

Not recommendations:

The following protocols are compiled from online communities and published literature. Pepbase does not endorse, recommend, or verify these protocols. They are provided for informational purposes only. Individual responses vary significantly. Consult a licensed medical professional before any use.

Reported GoalReported DoseReported FrequencyReported Route
Microbial infection control100 mcgonce dailySubcutaneous injection

⏱️Pharmacokinetics

Half-Life
30 min
Time to Peak
30 min
Clearance
2.5 hrs

⚡Reported Side Effects

This is not a complete list. Other side effects may occur.

Common
Histamine releasecommon (1-10%)
Serious / Rare
  • • Risk of developing autoimmune conditions
Injection-Specific Warnings
  • Use caution with MCAS or histamine sensitivity.

🧊Storage

Temperature
2-8°C
Reconstituted
Use within expiration
Shelf Life
6 months
Light Sensitive
Yes - protect from light
🛡️

Harm Reduction Information

Quality Concerns

  • Contamination with non-sterile water
  • Improper pH leading to irritation

Safety Tips

  • Always use bacteriostatic water for reconstitution.
  • Rotate injection sites to avoid skin damage.
  • Avoid exceeding recommended dose ranges initially.

Warning Signs to Stop

  • Severe allergic reactions
  • Persistent inflammation or discomfort at site
  • New or changed skin lesions

Seek Medical Help Immediately If

  • Severe pain or extensive ulceration at application site
  • Signs of systemic infection such as fever
❓

Frequently Asked Questions

How long until I see effects?

LL-37 typically shows initial effects within the first 1-2 weeks, particularly in wound healing contexts.

What time of day should I take it?

LL-37 is best taken in the morning to support daytime immune surveillance.

How can I minimize side effects?

To minimize side effects of LL-37, ensure proper dosing and sterile application or injection techniques.

Does tolerance develop?

There is no substantial evidence of tolerance development with LL-37, but individual responses can vary.

How should I store it?

LL-37 should be stored refrigerated at 2-8°C and protected from light to maintain efficacy.

Do I need to cycle it?

While specific cycling protocols for LL-37 are not detailed, follow recommended durations and protocols for safe use.

🔄

Reported Combinations

Compounds reported to be used alongside LL-37 in community discussions. Not a recommendation.

investigational

BPC-157

Enhanced wound healing and repair

investigational

TB-500

Complementary regenerative properties

investigational

Conventional Antibiotics

Increased antimicrobial efficacy

off label-medical

Vitamin D3

Supports immune function modulation

off label-medical

Lactoferrin

Combined immune boosting and antimicrobial effects

⚠️

Reported Interactions

Interactions reported in literature and community discussions.

Conventional antibioticsmoderate

Synergistic antimicrobial effects but monitor for hypersensitivity.

Vitamin D3minor

Supports immune modulation; generally safe to combine.

Lactoferrinminor

Compatible with potential immune support benefits.

NSAIDsminor

Potential for increased inflammation; monitor closely.

Alcoholmajor

Avoid due to enhanced inflammatory response risk.

Reconstitution Guide

Reconstitution Calculator

mL
U100 insulin syringe01020304050607080901001mL

100 units = 1 mL

Safety Tips

  • Always consult a licensed medical professional for dosing and reconstitution instructions.
  • Always double check your units. Mixing up mg and mcg can be very dangerous.
  • Make sure to select your syringe type. U-100 and U-50 syringes have different units.
  • Ensure you're not adding more BAC than your vial can hold. Most vials have maximum capacities listed.

This calculator is for informational and educational purposes only. It does not provide medical advice, dosing recommendations, or safety determinations. Reference ranges shown are compiled from publicly available sources and are not a substitute for guidance from a licensed healthcare professional.

Explore More Research

Browse our database of peptide research information compiled from published literature and community sources.

Browse All PeptidesAbout Pepbase App
📚

Other Sources & Citations

PubMed
The Potential of Human Peptide LL-37 as an Antimicrobial and Anti ...
pmc.ncbi.nlm.nih.gov•Updated Jan 2026
PubMed
Little peptide, big effects: the role of LL-37 in inflammation and ... - NIHpmc.ncbi.nlm.nih.gov › articles › PMC3836506
pmc.ncbi.nlm.nih.gov•Updated Jan 2026
PubMed
Ll-37 Signaling Through...
pmc.ncbi.nlm.nih.gov•Updated Jan 2026
PubMed
Repurposing human antibacterial peptide LL-37 for cancer ...
pmc.ncbi.nlm.nih.gov•Updated Dec 2025
PubMed
The Human Cathelicidin Antimicrobial Peptide LL-37 as a Potential ...
pmc.ncbi.nlm.nih.gov•Updated Oct 2025

Last updated: October 3, 2023

Important Disclaimer

AI-Generated Content Notice

The information on this page has been compiled using artificial intelligence (AI) and large language model (LLM) technology from multiple sources including published literature, online communities, and public databases. This content may contain errors, inaccuracies, outdated information, or omissions. We make no guarantees regarding the accuracy, completeness, or reliability of any information presented. You are solely responsible for independently verifying any information before relying on it.

Not Medical Advice

Nothing on this website constitutes medical advice, diagnosis, or treatment recommendations. The information provided is for educational and harm-reduction purposes only. We do not provide individualized dosing guidance or treatment recommendations. Protocols and dosing information shown represent reports from community discussions and published literature—they are not endorsements or recommendations. Always consult with a licensed healthcare professional before making any health-related decisions.

No Endorsement of Use

Pepbase does not endorse, encourage, or recommend the use of any peptide or substance discussed on this website. Many compounds discussed are not approved for human use by the FDA or other regulatory agencies. Some substances may be illegal to possess, sell, or use in your jurisdiction. We do not facilitate or encourage the procurement, distribution, or use of controlled or prescription-only substances. Users are solely responsible for understanding and complying with all applicable laws in their jurisdiction.

Calculators and Tools

Any calculators, estimators, or tools provided on this website are for informational purposes only and produce estimates that may be inaccurate. Errors in calculations can result in serious harm. You are solely responsible for verifying all calculations independently. These tools do not account for individual factors that may affect dosing and should never be relied upon as a substitute for professional medical guidance.

Assumption of Risk

By using this website, you acknowledge that you understand the risks associated with using unregulated substances and that you assume full responsibility for your own health decisions. Pepbase, its creators, contributors, and affiliates disclaim all liability for any harm, injury, or damages arising from the use or misuse of information on this website. Use of any information on this site is entirely at your own risk.

If you are experiencing a medical emergency, call emergency services immediately. If you have questions about medications or supplements, consult a licensed pharmacist or physician.

Pepbase — Your peptide companion

© 2026 Pepbase. All rights reserved.