LL-37
The only human cathelicidin: an endogenous antimicrobial and immunomodulator; the research vial is not an approved antibiotic.
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Quick summary
LL-37 is the active C-terminal fragment of hCAP18, the only human cathelicidin. It is an amphipathic cationic peptide with antibacterial, antiviral, antifungal, anti-biofilm, and immunomodulatory (chemotaxis, LPS, wound healing) activity. This does not mean that injecting a “LL-37 research” vial is safe or effective: the peptide can be cytotoxic at high concentrations, it degrades, and its role in autoimmunity is a double-edged sword.
Studied for
How it works
Permeabilizes microbial membranes; binds LPS/LTA; modulates receptors on immune and epithelial cells; promotes re-epithelialization in models. It can also promote inflammation depending on the context.
What the research says
Solid reviews on the biology of the endogenous peptide (PMC8227053, etc.). Clinical: interest in wound/ulcer healing with topical LL-37 (e.g., ropocamptide / leg trials); there is no approved systemic standard. Limitations: cellular toxicity, proteolytic instability, cost, reduced activity in physiological fluids.
Evidence level
C — extensive endogenous human biology + limited topical trials; systemic research = weak
What's most reported
- Broad antimicrobial activity in vitro
- Interest in chronic wounds (investigational topical)
- In communities: “immunity / gut / Lyme” — anecdotal
Common side effects
Cytotoxicity/hemolysis at high doses in vitro; possible inflammatory or autoimmune exacerbation depending on the context. Systemic profile of research vials: not characterized.
Combines / does not combine
Does not replace indicated antibiotics. Caution in active autoimmune diseases (dual role of the peptide). No validated stacks.
Frequently asked questions
No.
Because of the resistance crisis and because it is a well-studied human innate effector in the laboratory.
There is no evidence that the research vial safely improves immunity in healthy people.
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Educational content. Not medical advice or usage guidance. Research products are not approved drugs unless otherwise stated.