What is the difference between ll37 and LL-37?

ll37 and LL-37 refer to the same peptide — the cathelicidin antimicrobial peptide. LL-37 is the standard scientific notation (named for the two leucines at its N-terminus and its 37 amino acid length). The lowercase 'll37' is a common search variant. Both terms refer to the identical compound.

Is LL-37 on the WADA prohibited list?

Yes. LL-37 is prohibited under WADA's S0 (Non-Approved Substances) category because it is not approved by any major regulatory authority (FDA, EMA) for therapeutic use. Athletes competing in WADA-regulated sports should not use LL-37.

What are the main benefits of LL-37 peptide?

LL-37 research focuses primarily on antimicrobial activity (against bacteria, viruses, and fungi), wound healing acceleration, and immune modulation. In vitro studies show anti-biofilm properties. Some preclinical research explores anti-inflammatory and potential anti-cancer applications, though human clinical trial data is limited.

Content reviewed by clinical research staff

Last reviewed: March 2026Sources: PubMed, FDA, WADA Prohibited List

Evidence graded using the PeptideScholar A-D system.

LL-37

Antimicrobial peptide (cathelicidin)37 amino acids

CPreclinical

Good Credibility

2 cited studies | Evidence level C

Not FDA ApprovedWADA Banned

LL-37 (also written as ll37 or ll-37) is the only cathelicidin antimicrobial peptide found in humans. It plays a crucial role in innate immune defense, wound healing, and inflammation modulation.

Mechanism of Action

Disrupts microbial membranes through electrostatic interaction with negatively charged phospholipids. Also modulates immune cell chemotaxis, inflammatory cytokine release, and promotes angiogenesis.

Benefits

Broad-spectrum antimicrobial activity (bacteria, fungi, viruses)^[2]
Immune modulation and anti-biofilm effects^[1]
Wound healing promotion^[1]^[2]
Potential anti-cancer properties in preclinical models^[2]

This content is for informational purposes only and does not constitute medical advice.

LL-37 - Dosing in Published Research

Reported routes: Subcutaneous injection, Topical

Research dosing varies widely. Topical wound studies used 1-10 mcg/mL concentrations. No established systemic dosing.

The dosing information above is sourced from published research literature and clinical trials. These are not recommendations. Individual responses vary. Always consult a healthcare provider before considering any peptide-based therapy.

Side Effects

Limited human safety data for therapeutic use
Potential pro-inflammatory effects at high concentrations^[1]
Injection site reactions^[1]
Theoretical cytotoxicity at elevated doses^[1]

Considering peptide research?

LL-37 is not FDA-approved. Always consult a licensed healthcare provider before considering any peptide.

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Research & Evidence

ReviewPMID: 30980360

Design of Antimicrobial Peptides: Progress Made with Human Cathelicidin LL-37.

Adv Exp Med Biol, 2019

Comprehensive review of LL-37 antimicrobial, immunomodulatory, and wound healing functions in human innate immunity

In VitroPMID: 29737589

LL-37 fragments have antimicrobial activity against Staphylococcus epidermidis biofilms and wound healing potential in HaCaT cell line.

J Pept Sci, 2018

Review of LL-37 therapeutic applications including chronic wounds, infections, and cancer with discussion of delivery challenges

Compare LL-37 With

LL-37 vs BPC-157

LL-37 vs TB-500

References

1.Design of Antimicrobial Peptides: Progress Made with Human Cathelicidin LL-37.. Adv Exp Med Biol, 2019. "Comprehensive review of LL-37 antimicrobial, immunomodulatory, and wound healing functions in human innate immunity" [PMID: 30980360]
2.LL-37 fragments have antimicrobial activity against Staphylococcus epidermidis biofilms and wound healing potential in HaCaT cell line.. J Pept Sci, 2018. "Review of LL-37 therapeutic applications including chronic wounds, infections, and cancer with discussion of delivery challenges" [PMID: 29737589]

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LL-37 FAQ

Medical Disclaimer

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

Always consult a qualified healthcare provider before starting, stopping, or modifying any treatment. Do not disregard professional medical advice based on information found on this site.

No claims of therapeutic efficacy are made for substances that are not FDA-approved for the discussed indications. Research citations reflect published findings and do not imply endorsement.

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