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InflammationAnimal / preclinical only

LL-37

Human cathelicidin antimicrobial peptide. Endogenous component of innate immunity with broad-spectrum antimicrobial, immunomodulatory, and wound-healing activity. Researched as a topical and systemic therapeutic across multiple indications; no FDA-approved formulation yet.

Educational only — not medical advice. SmartPeptide does not prescribe, diagnose, or treat. Always consult a licensed healthcare provider before using any peptide, supplement, medication, or protocol.

What the research shows

Robust in-vitro and animal-model evidence for antimicrobial activity (including biofilm disruption), wound healing acceleration, and immunomodulation. Small human topical trials suggest promise for chronic wounds. No approved systemic indication.

What's still experimental

Most therapeutic applications. Optimal route, dose, formulation, and safety profile in systemic use are unknown.

Anecdotal / community reports

Community use for chronic infections, Lyme disease, biofilm-related conditions. These uses are not supported by published RCTs and may risk LL-37's known pro-inflammatory effects in susceptible individuals.

Anecdotal reports are NOT scientific evidence. They reflect personal experience and may not generalize.

FDA approval status

Source: openFDA + DailyMed (NIH/NLM)
No FDA-approved drug label exists for “LL-37”. This peptide is not currently approved by the FDA as a finished pharmaceutical product. Any commercial product claiming FDA approval should be treated with suspicion.

Doses studied in research

Source: Published clinical trial

What published trials tested or FDA-approved labels specify. Reporting research facts — not a SmartPeptide recommendation.

⚠ HAZARD WARNING — read before considering doses below

LL-37 has documented pro-inflammatory effects in autoimmune contexts (psoriasis, lupus). Anyone with autoimmune disease should specifically discuss this with a rheumatology-informed clinician before considering.

Community-anecdotal range — NOT a SmartPeptide recommendation

The doses below are aggregated from research-peptide community forums (Reddit, biohacker discussions). They are NOT supported by clinical trials, NOT FDA-approved, and NOT a SmartPeptide recommendation. Source purity, dose accuracy, and user-reported outcomes are unverifiable. We display this only because the information is publicly available elsewhere — visitors should absolutely consult a licensed clinician familiar with experimental peptides before any use.

Community-anecdotal — not evidence-basedChronic-infection / Lyme community forums
Indication studied: Community-discussed for antimicrobial / biofilm contexts (no FDA approval; mostly preclinical evidence)
Typical
100µg
daily · subcutaneous

Most-discussed range

Open calculator
Maximum
200µg
daily · subcutaneous

Higher community range

Open calculator

Notes from the source: LL-37 can be pro-inflammatory in certain contexts (psoriasis, lupus). Systemic safety data in humans is sparse.

Important framing: The numbers above are what published trials tested or what FDA-approved labels specify. They are NOT a SmartPeptide recommendation for you. Trial doses come paired with screening, monitoring, and clinician oversight. Always consult a licensed clinician before any peptide use.

How clinicians typically protocol this

Third-party reference · not our recommendation

Dosing phases, cycle lengths, and administration timing as listed in a compounding-pharmacy clinician reference guide. Shown so you can see what a real protocol looks like — and bring informed questions to a licensed clinician.

Third-party protocol referenceCompounding-pharmacy clinician protocol reference (Nov 2025)

Dose numbers, frequencies, and cycle lengths in this panel are extracted from a clinician-facing reference protocol distributed by a US-based compounding pharmacy in November 2025. SmartPeptide has paraphrased all descriptive text and adds no endorsement. Always consult a licensed clinician.

Additional caution for LL-37

LL-37 has been implicated in autoimmune pathology (psoriasis, lupus flares). Avoid in known autoimmune disease unless a clinician directs otherwise.

Immune Support

Only known human cathelicidin peptide; antimicrobial and immunomodulatory.

Protocol phases

Antimicrobial
1–2 mgdaily (often split into 2–3 doses)
subcutaneous
Wound healing (topical)
0.5–1 mg1–2× daily
topical

in a carrier solution/gel

Low-dose research
100–200 µgdaily
subcutaneous
Reported side effects
Mild flu-like symptomsSkin flushing / warmth post-injectionTransient worsening of inflammation at old injury sitesBrain fog or fatigue for 24–72 hr

Protocol notes: The reference suggests hydration, sleep, and possibly co-administering BPC-157 or KPV to buffer inflammatory response.

Reconstitution calculator Storage & reconstitution guide
Not medical advice. SmartPeptide does not prescribe, diagnose, or treat. The protocol above reproduces dose figures from a third-party clinician reference so you can see what compounding-pharmacy guidance typically looks like — it is not a recommendation for you, and it has not been validated against peer-reviewed dose-ranging trials. Many of these compounds are not FDA-approved for human use. Work with a licensed clinician familiar with peptide therapy before considering anything here.

FDA enforcement & recalls

Live · openFDA Drug Enforcement API
Total actions
2
recalls + withdrawals
Ongoing
1
not yet completed
Class I (serious)
0
health hazard / death risk
  • Class IITerminated· Voluntary: Firm initiated
    FDA record

    LL-37 2 mg/mL (5 mL) Injection, 5 mL vials, Rx only, Farmakeio 1736 N Greenville Ave Richardson, TX 75081 USA

    Reason: Lack of Assurance of Sterility: deviations from Current Good Manufacturing Practices (CGMP) that call into question the sterility of products intended to be sterile.

    Apr 5, 2022·North American Custom Laboratories, LLC dba FarmaKeio Superior Custom Compounding
  • Class IIOngoing· Voluntary: Firm initiated
    FDA record

    LL-37, 2000 MCG/ML, 2 ML vial, The Guyer Institute of Molecular Medicine, Indianapolis, IN

    Reason: Lack of Assurance of Sterility: due to concerns with production processes which cannot assure sterility of products intended to be sterile.

    Nov 30, 2020·Advanced Nutriceuticals, LLC
FDA classifications: Class I = reasonable probability of serious adverse health consequences or death. Class II = temporary or medically reversible adverse consequences. Class III = unlikely to cause adverse health consequences.

Mechanism & targets

ChEMBL · UniProt · Open Targets

Molecule (ChEMBL)

View on ChEMBL
Formula
C205H341N61O52

Protein targets (UniProt)

  • Cathelicidin antimicrobial peptide
    P49913gene: CAMPHomo sapiens· 170 aaReviewed

    Antimicrobial protein that is an integral component of the innate immune system (PubMed:14978112, PubMed:16637646, PubMed:18818205, PubMed:22879591, PubMed:9736536). Binds to bacterial lipopolysaccharides (LPS) (PubMed:16637646, PubMed:18818205). Acts via neutrophil N-formyl peptide receptors to enhance the release of CXCL2 (PubMed:22879591). Postsecretory processing generates multiple cathelicidin antimicrobial peptides with various lengths which act as a topical antimicrobial defense in sweat…

  • Cathelicidin antimicrobial peptide
    Q1KLX2gene: CAMPPongo pygmaeus· 170 aaReviewed

    Antimicrobial protein that is an integral component of the innate immune system (By similarity). Binds to bacterial lipopolysaccharides (LPS) (By similarity). Acts via neutrophil N-formyl peptide receptors to enhance the release of CXCL2 (By similarity). Postsecretory processing generates multiple cathelicidin antimicrobial peptides with various lengths which act as a topical antimicrobial defense in sweat on skin (By similarity). The unprocessed precursor form, cathelicidin antimicrobial peptid…

  • Cathelicidin antimicrobial peptide
    Q1KLX7gene: CAMPMacaca fascicularis· 170 aaReviewed

    Antimicrobial protein that is an integral component of the innate immune system (By similarity). Binds to bacterial lipopolysaccharides (LPS) (By similarity). Acts via neutrophil N-formyl peptide receptors to enhance the release of CXCL2 (By similarity). Postsecretory processing generates multiple cathelicidin antimicrobial peptides with various lengths which act as a topical antimicrobial defense in sweat on skin (By similarity). The unprocessed precursor form, cathelicidin antimicrobial peptid…

Live research

PubMed · ClinicalTrials.gov · Europe PMC · OpenAlex
PubMed papers
4,217
total
Human studies
0
MeSH: humans
Clinical trials
0
published
Active trials
6
98 total registered

Europe PMC — 193,097 additional records

Includes EU/UK studies and PubMed Central full-text articles. Often surfaces research weeks before PubMed indexes it.

Research volume (OpenAlex topic graph)

Total works
1,357,481
all years
Last 5 years
467,473
recent activity
Open access
1,327,573
freely readable
OA share
98%
of all works

Human clinical evidence

Semantic Scholar · AI TLDRs · influence-ranked
Semantic Scholar API is currently rate-limited.

Human-study summaries for “LL-37 OR cathelicidin LL-37” are available on Semantic Scholar but the shared free-tier API quota is exhausted right now. Try refreshing in a few minutes, or check the PubMed and Europe PMC panels above for the same literature.

Research funding & verification

NIH RePORTER · CrossRef DOI registry

NIH-funded research

U.S. National Institutes of Health
Funded projects
142
all years
Top award sum
$22.6M
aggregate USD
Years covered
20
research span
Largest active / recent grants

Publication landscape

CrossRef · DOI registry
Indexed works (CrossRef)
1,814,446
all DOIs registered
Retracted papers
0
no retractions on record
Top funders of indexed research
  • National Natural Science Foundation of China31,094 works
  • National Science Foundation4,181 works
  • National Key Research and Development Program of China4,007 works
  • National Institutes of Health3,706 works
  • Fundamental Research Funds for the Central Universities3,134 works
  • National Research Foundation of Korea2,597 works

Funder diversity is a credibility signal. Research concentrated in a single drug company's funding warrants more scrutiny than research funded across NIH, charities, and academic grants.

Preprints — cutting edge

bioRxiv · medRxiv · via Europe PMC

Preprints have NOT been peer-reviewed. They are early research shared by authors before formal validation. Treat findings as preliminary.

Showing 6 of 2,004 preprints indexed by Europe PMC.

Known risks

Cytotoxicity at high concentrations (LL-37 can be toxic to human cells, not just bacteria). Pro-inflammatory effects in certain contexts (psoriasis, lupus). Limited human pharmacokinetic data.

Reported side effects

Topical: skin irritation. Systemic: poorly characterized in humans. Theoretical immune-modulation concerns.

FDA adverse event reports (FAERS)

Updated quarterly by FDA
No reports found in the FDA Adverse Event Reporting System for “LL-37”. This is normal for research-only peptides that are not marketed as FDA-approved drugs.

What requires medical supervision

Not FDA-approved. Should only be considered under a clinician familiar with antimicrobial peptide research.

Questions for your clinician

  • Is there published human evidence for my specific indication?
  • What's the risk of immune dysregulation in my case?
  • Are there FDA-approved alternatives we should try first?

Editorially curated references

Discussions about LL-37

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