LL-37
Also known as: Cathelicidin, CAMP, hCAP-18
LL-37 is the only human cathelicidin, a natural antimicrobial peptide with broad-spectrum activity. It plays a crucial role in innate immunity and wound healing.
Research Status
Research compound
For research purposes only. Not approved for human use. Not medical advice.
Research Areas
Side Effects
Localized erythema, mild pain, or transient swelling at the injection site typically resolves within 24 hours. Rotate injection sites to minimize recurrence. Apply ice if needed for comfort.
May occur 2–6 hours post-injection as part of normal immune activation. Typically self-resolving within 12–24 hours. Stay hydrated and monitor temperature.
Mild headache may occur within hours of injection. Usually resolves without intervention; over-the-counter analgesics may be used if needed.
Transient tiredness or general malaise may occur as part of immune system activation. Typically resolves within 24–48 hours. Ensure adequate rest and hydration.
Mild nausea has been reported in some users. Usually self-resolving. Avoid heavy meals immediately before or after injection.
Repeated injections at the same site can cause localized fat loss (lipoatrophy) or fat accumulation (lipohypertrophy). Strict site rotation prevents this. If lipodystrophy develops, discontinue injections at that site and allow 4–8 weeks recovery.
Allergic reactions including urticaria, angioedema, or anaphylaxis are rare but possible. Seek immediate medical attention if difficulty breathing, throat swelling, or severe rash occurs. Discontinue use and do not re-inject.
In rare cases, excessive immune stimulation may occur, particularly with high doses or frequent injections. Symptoms may include prolonged fever, severe fatigue, or lymphadenopathy. Reduce dose or frequency and consult a healthcare provider.
Dosing Reference
| Parameter | Value |
|---|---|
| Dose range | 5-10 mg |
| Frequency | 2-3x weekly |
| Timing | As needed for immune support |
| Route | Subcutaneous, Intramuscular |
Often used during illness or for chronic infections. Cycle usage.
Research disclaimer
Figures drawn from published research literature and community logs. Not clinical recommendations. Consult a qualified professional. Research use only.
Reconstitution Guide
Do not use saline or bacteriostatic saline — use only bacteriostatic water for reconstitution
Do not shake the vial vigorously; gentle swirling prevents peptide degradation
Discard immediately if the solution appears cloudy, discolored, or contains visible particles
Use within 30 days of reconstitution when stored at 2–8°C
Do not freeze the reconstituted solution; freezing may denature the peptide
Use the PeptideVolt reconstitution calculator for your exact concentration
Molecular and Pharmacological Data
| Molecular weight | 4493 |
| Sequence | LLGDFFRKSKEKIGKEFKRIVQRIKDFLRNLVPRTES |
LL-37 is the only endogenous human cathelicidin antimicrobial peptide, functioning as a direct-acting antimicrobial agent and immune modulator. It disrupts bacterial and fungal cell membranes through electrostatic and hydrophobic interactions, while also activating innate immune receptors (particularly formyl peptide receptor-like 1, FPRL1) to enhance neutrophil recruitment, promote wound healing, and regulate inflammatory responses. LL-37 bridges innate and adaptive immunity by enhancing antigen presentation and modulating cytokine production.
Direct Antimicrobial Activity
LL-37 inserts into bacterial and fungal cell membranes, disrupting membrane integrity and leading to cell lysis. This broad-spectrum activity covers gram-positive and gram-negative bacteria, fungi, and some enveloped viruses.
FPRL1 (Formyl Peptide Receptor-Like 1) Signaling
LL-37 binds to FPRL1 on immune cells (neutrophils, macrophages, dendritic cells), triggering chemotaxis, respiratory burst, and enhanced phagocytosis. This amplifies the innate immune response to pathogens.
Wound Healing and Tissue Repair
LL-37 stimulates fibroblast migration and proliferation, promotes angiogenesis, and enhances epithelial cell growth. It also reduces excessive inflammation, creating an environment conducive to tissue remodeling.
Inflammatory Modulation
LL-37 regulates TLR signaling and NF-κB pathways, balancing pro-inflammatory and anti-inflammatory cytokine production. This prevents excessive inflammation while maintaining effective immune defense.
- LL-37 is derived from the C-terminal of human cathelicidin hCAP18 and is the only cathelicidin naturally produced in humans
- Deficiency or dysfunction of LL-37 is associated with increased susceptibility to infections and impaired wound healing
- LL-37 has antimicrobial activity against a broad spectrum of pathogens including Staphylococcus aureus, Pseudomonas aeruginosa, Candida species, and some viruses
- Beyond direct antimicrobial effects, LL-37 acts as a damage-associated molecular pattern (DAMP) that activates pattern recognition receptors and bridges innate and adaptive immunity
- LL-37 concentrations are naturally elevated during infection and inflammation, and are reduced in certain chronic inflammatory conditions
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View all peptidesResearch Use Only. All content on this page is provided for informational and educational purposes related to scientific research. LL-37 is not approved for human use by the FDA or any equivalent regulatory body. This is not medical advice. Do not use any substance discussed here for therapeutic, diagnostic, or preventative purposes. Consult a qualified healthcare professional before making any health-related decisions. The Peptide Volt does not endorse the use of any research chemicals. 18+ only.