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Immune

LL-37

Human cathelicidin antimicrobial peptide LL-37 (37 amino acids)

Human cathelicidin peptide research examining antimicrobial defense, immune signaling, and wound healing.

Limited Human Evidence

Route

Subcutaneous in the community experimental protocol

Common format

5 mg vial

Research focus

antimicrobial defense

Evidence level

Limited Human Evidence

Typical cycle

8–12 weeks

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LL-37 in 30 seconds

Atlas Fast Read

What it is

Human cathelicidin antimicrobial peptide LL-37 (37 amino acids)

Why people care

Human cathelicidin peptide research examining antimicrobial defense, immune signaling, and wound healing.

Human evidence

Limited Human Evidence — Human interventional or clinical data exist, but studies are small, early-phase, mixed, indirect, route-specific, or not confirmatory.

Biggest misconception

Key gaps include larger independent trials, clearer dose-response data, long-term safety, clinically meaningful endpoints, and evidence that findings generalize beyond the narrow populations or routes already studied.

Bottom line

LL-37 has a real human signal or documented human pharmacology, but evidence is too small, mixed, route-specific, or indication-specific to justify broad claims.

Overview

What is LL-37?

LL-37 is human cathelicidin antimicrobial peptide LL-37 (37 amino acids). Human cathelicidin peptide research examining antimicrobial defense, immune signaling, and wound healing.

LL-37 was characterized as the active C-terminal peptide of the human cathelicidin precursor hCAP18 in the 1990s. It became a major innate-immunity research target because of its antimicrobial and immunomodulatory actions.

Mechanism

How it works

Directly disrupts microbial membranes and also acts as an immune signaling molecule, influencing chemotaxis, cytokines, epithelial repair, angiogenesis, and biofilm biology. Effects can be protective or pro-inflammatory depending on context.

Research areas

antimicrobial defensebiofilmswound healinginnate immunity

Evidence

What does the evidence actually say?

Limited Human Evidence

Human interventional or clinical data exist, but studies are small, early-phase, mixed, indirect, route-specific, or not confirmatory.

01

Preclinical Evidence

02

Limited Human Evidence

03

Strong Human Evidence

Human evidence

Human translational and early clinical research exists around LL-37 biology, wound healing, and infection, but systemic therapeutic use is not established. The peptide can be both antimicrobial and pro-inflammatory, complicating translation.

Preclinical evidence

Extensive cell and animal work shows antimicrobial activity, biofilm effects, immune modulation, angiogenesis, and epithelial repair. The same pleiotropy can also promote inflammation, making dose and context critical.

Knowledge gaps

Key gaps include larger independent trials, clearer dose-response data, long-term safety, clinically meaningful endpoints, and evidence that findings generalize beyond the narrow populations or routes already studied.

Protocol

Research protocol

DoseFrequencyTimingCycle

Dose

Community research reference: 50–400 mcg/day with gradual titration. No validated therapeutic human dose exists for systemic LL-37.

Frequency

Once daily in the community protocol; some community schedules use 5 days on / 2 days off.

Timing

No established time-of-day requirement.

Route

Subcutaneous in the community experimental protocol; most human translational work is not an established systemic therapy.

Cycle length

8–12 weeks

Reconstitution

Community reference: 0.5 mL bacteriostatic water per 5 mg vial = 10 mg/mL.

Storage

Community reference: lyophilized frozen; reconstituted 2–8 °C; avoid repeated freeze-thaw.

Monitoring

CBC, CMP and inflammatory markers may be reasonable in supervised research, but no validated monitoring algorithm exists. Watch closely for inflammatory or hypersensitivity reactions.

Protocols vary widely between sources. Investigational compounds are not approved therapies, and approved products should follow their official labeling. Nothing here is medical advice.

Safety

Safety, side effects, and precautions

Side effects

Systemic human safety is poorly characterized. LL-37 can be pro-inflammatory as well as antimicrobial, so pain, inflammation, fever-like symptoms, hypersensitivity and tissue irritation are plausible concerns.

Contraindications

No approved contraindication profile exists. Avoid unsupervised systemic use in autoimmune/inflammatory disease, pregnancy/breastfeeding, active malignancy or severe infection requiring established antimicrobial therapy.

Interactions

Formal interaction data are lacking. Antibiotics, immunomodulators and anti-inflammatory therapies may alter the same host-defense pathways; LL-37 should not replace indicated antimicrobial treatment.

Stacks

Common stacks

No well-supported stack is highlighted for this peptide yet.

Questions

FAQ

References

Sources

Atlas

The Atlas verdict

LL-37 has a real human signal or documented human pharmacology, but evidence is too small, mixed, route-specific, or indication-specific to justify broad claims. The most defensible use of the literature is to separate what has actually been measured in people from what is still extrapolated from mechanism or animal work.

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