LL-37: the complete guide
LL-37 is the active C-terminal fragment of the human cathelicidin hCAP-18. It has broad-spectrum antimicrobial activity and immunomodulatory effects, and is studied in wound healing, chronic infection, and immune-dysfunction research.
How LL-37 works
LL-37 disrupts bacterial membranes via amphipathic interaction and also modulates host immune signaling — chemotaxis, cytokine modulation, epithelial repair. Concentrations for antimicrobial vs immunomodulatory effects differ.
Typical LL-37 dosage
Commonly reported research ranges: 1–5 mg per injection (research protocols vary).
Dose should always be individualized. Factors that influence it include bodyweight, research goal, tolerance, and specific compound batch. The information below is educational, not a prescription.
How to reconstitute LL-37
A widely used reconstitution for a 5 mg vial is 2 ml of bacteriostatic water. With a typical 1000 mcg dose this works out to the unit count shown in the calculator below.
Half-life and administration frequency
Approximately 1–2 hours (plasma).
This half-life informs how often LL-37 is typically dosed. Shorter half-lives usually mean more frequent dosing to maintain plasma levels; longer half-lives allow daily, weekly, or less-frequent administration depending on the compound.
Reported side effects
- Injection-site reactions
- Potential host cell toxicity at high concentrations
- Limited human safety data
This list reflects effects reported in available literature or user logs. It is not exhaustive. Adverse reactions should be discussed with a qualified clinician.
Common LL-37 stacks
- BPC-157 (wound-healing research)
- TB-500
Storage and handling
Lyophilized: refrigerated or frozen. Reconstituted: refrigerated, use within 14 days.
FDA and regulatory status
Not FDA approved. Research use only in the US.
LL-37 clinical trials and evidence
For clinical-trial and primary-literature context, start with the sources below. We prioritize official drug labels, ClinicalTrials.gov records, and PubMed-indexed literature when available.
- LL-37 clinical trial records — ClinicalTrials.gov
Track your LL-37 protocol on iPhone
Peptide Protocol logs every dose, calculates reconstitution for you, and keeps your full protocol on one calm screen.
See the app →Frequently asked questions
What is LL-37?
LL-37 is the active C-terminal fragment of the human cathelicidin hCAP-18. It has broad-spectrum antimicrobial activity and immunomodulatory effects, and is studied in wound healing, chronic infection, and immune-dysfunction research.
How does LL-37 work?
LL-37 disrupts bacterial membranes via amphipathic interaction and also modulates host immune signaling — chemotaxis, cytokine modulation, epithelial repair. Concentrations for antimicrobial vs immunomodulatory effects differ.
What is a typical LL-37 dose?
Commonly reported ranges are 1–5 mg per injection (research protocols vary). This is research information, not a recommendation — dosing should be individualized under clinical guidance.
What is the half-life of LL-37?
Approximately 1–2 hours (plasma). This influences how often it is administered.
How do you reconstitute LL-37?
A common approach is to add 2 ml of bacteriostatic water to a 5 mg vial. Use the reconstitution calculator for exact unit counts.
What are the side effects of LL-37?
Injection-site reactions; Potential host cell toxicity at high concentrations; Limited human safety data.
Is LL-37 FDA approved?
Not FDA approved. Research use only in the US.
Are there clinical trials for LL-37?
Registered or published clinical-trial sources for LL-37 are listed in the references section below. Evidence depth varies widely by compound, so check the cited trial registries and primary literature before relying on any claim.
References
- LL-37 / cathelicidin literature — National Library of Medicine. Primary research on LL-37 antimicrobial and immunomodulatory activity
- Dürr et al. — LL-37 antimicrobial mechanisms — PubMed. Foundational structural and mechanistic reviews
- LL-37 clinical trial records — ClinicalTrials.gov. Registered human studies across wound healing and infection
Sources listed above were used to verify the claims on this page. See our editorial policy for how we source information.
Educational use only. Peptide Protocol is an informational tool. Nothing on this page constitutes medical advice. Many peptides are prescription-only or restricted in your jurisdiction. Always consult a licensed healthcare professional before injecting any compound.