# LL-37

> LL-37 is the only cathelicidin-family antimicrobial peptide produced in humans, generated by cleavage of the precursor protein hCAP18 and expressed by immune cells, epithelial cells, and skin. It has been studied for its dual role in direct antimicrobial defense and in modulating innate immune responses and wound healing. Research spans infectious disease, dermatology, and inflammatory bowel conditions. LL-37 also has a complex relationship with inflammation, since dysregulated levels have been associated with autoimmune conditions such as psoriasis and lupus, making its net effects context-dependent.

- URL: https://www.lifeconverted.com/peptides/ll-37
- Primary category: Anti-Inflammatory
- Effectiveness rank: #11 in Healing & Recovery; #5 in Immune & Anti-Aging; #7 in Anti-Inflammatory
- Evidence level: Moderate evidence
- Route: Subcutaneous
- Dose range: 50-200 mcg
- Dose tiers: low 50 mcg; moderate 100 mcg; high 200 mcg
- Half-life: Short, estimated at under 1 hour, though local tissue effects may persist longer
- Timing: Morning
- Cycle: 2-4 weeks on, 4 weeks off (Short courses are typically favored given its complex, context-dependent immune signaling role)
- Storage: Store lyophilized peptide frozen; reconstituted solution refrigerated and used within 2 weeks

## Mechanism of action

LL-37 disrupts microbial cell membranes directly, contributing to broad-spectrum antimicrobial activity against bacteria, fungi, and some viruses. It also engages immune cell receptors, including formyl peptide receptor 2, to modulate chemotaxis, cytokine release, and wound-healing processes such as angiogenesis and re-epithelialization. Because it can promote or dampen inflammation depending on tissue context and concentration, its immunomodulatory role is considered more nuanced than purely anti-inflammatory.

## Reported benefits

- Studied for broad-spectrum antimicrobial defense
- Explored for supportive roles in wound healing and tissue repair
- Investigated for immune modulation in infection contexts
- May support skin barrier function research

## Reported side effects

- Injection site irritation
- Theoretical risk of pro-inflammatory effects in susceptible individuals given its complex immune role
- Limited human dosing and long-term safety data
- Possible flushing

## Common protocols

- Short daily subcutaneous courses focused on infection recovery or wound support

## Stacking notes

Sometimes discussed alongside healing-focused peptides such as BPC-157; caution urged given LL-37's dual pro- and anti-inflammatory potential

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Educational information only, not medical advice. Full disclaimer: https://www.lifeconverted.com/disclaimer