LL-37 (Cathelicidin)
Get a source-linked, educational explanation from this profile.
Complete Research Guide
Open each section for the available evidence. Gaps are stated rather than inferred.
Overview
LL-37 (Cathelicidin) is listed as antimicrobial / wound healing.
- •Antimicrobial
- •Wound healing
- •Immunomodulation
Regulatory status: Not FDA-approved; research use.
Structure & Properties
Compound: LL-37 (Cathelicidin); also known as hCAP18 peptide.
Pharmacologic class: Antimicrobial / Wound Healing.
Known delivery routes: Topical, Intralesional (research).
Sequence, molecular weight, salt form, and excipient details are formulation-specific and are not listed unless verified by a manufacturer or laboratory COA.
How It Works
Human cathelicidin antimicrobial peptide — disrupts bacterial membranes; modulates TLR signaling; promotes keratinocyte migration; anti-biofilm.
- •Broad antimicrobial activity
- •Wound healing in models
- •Biofilm disruption
Human Research
Evidence grade: Pre-clinical / Observational
Evidence is primarily preclinical or observational; human effectiveness and long-term safety are not established.
Laboratory Research
Pre-clinical and in vitro primarily
Preclinical findings describe biological plausibility, not proven benefit in people. Animal and laboratory doses do not translate directly to human use.
Processing & Interactions
Timing and exposure
Daily SubQ, morning. Short cycles (2–4 weeks) to minimize immune fatigue.
Potential interactions and combinations to avoid
- •Autoimmune flares — may aggravate
Absorption, half-life, metabolism, and clearance can vary by formulation and route. Use prescribing information when an approved product exists.
Safety & Precautions
Known or reported risks
- •Pro-inflammatory at high doses
- •Potential oncogenicity in some cancer models
Contraindications
- •Active malignancy (theoretical)
- •Pregnancy
- •Autoimmune disease in active flare (immune activation may worsen symptoms)
- •Solid-organ or stem-cell transplant recipients on immunosuppression (rejection risk)
- •Concurrent biologic immunosuppressants or systemic corticosteroids without specialist input
- •Untreated acute infection requiring standard antimicrobial therapy
- •Broken, infected, sunburned, or actively inflamed skin
- •Concurrent prescription retinoid, chemical peel, or laser resurfacing without dermatologic guidance
- •Known copper sensitivity or Wilson's disease (copper-carrier peptides)
- •Eczema, rosacea, or perioral dermatitis in active flare
- •Systemic inflammatory disease such as psoriasis or lupus (LL-37 is an autoantigen)
- •Not FDA-approved for human therapeutic use — no verified purity, sterility, or potency standards
- •Immunocompromised or transplant patients (unverified sterility and immunogenicity risk)
- •Concurrent participation in drug-tested sport (WADA prohibited or non-cleared substance)
- •Known hypersensitivity or prior reaction to this compound or any excipient/diluent
- •Pregnancy, attempting conception, or breastfeeding unless prescribed and monitored by a physician
- •Children and adolescents with open growth plates (unless under specialist endocrine care)
- •Active or recently treated malignancy without oncology clearance
- •Use without a confirmed diagnosis, baseline labs, and licensed clinical supervision
Unknown long-term toxicity should be assumed where controlled human data are limited. Seek urgent care for a severe or unexpected reaction.
Administration & Studied Formulations
Reference range: Not standardized for human use
Frequency: Variable
Cycling: Not standardized.
Topical
Cosmetic / dermal repair peptides applied directly to skin.
Serum, cream, or gel formulation. Apply to clean dry skin AM/PM. Wait 60–90 sec before layering moisturizer or sunscreen. Separate copper peptides from vitamin C / AHA by ≥12 hrs (copper is destabilized).
Dosing information is educational context, not a personal recommendation. Approved products must follow their label and prescriber instructions.
Applications & Related Therapies
Potentially complementary measures
- •Thymosin Alpha-1
Clinical use should account for diagnosis, approved alternatives, nutrition, activity, sleep, rehabilitation, current medicines, and appropriate monitoring.
Cases, Considerations & Ethics
Decision framework: establish the clinical goal, confirm evidence quality and legal status, screen contraindications and interactions, compare approved alternatives, define monitoring and stopping criteria, and use shared decision-making with a licensed clinician.
Case evidence: individual reports cannot establish safety or effectiveness and should not outweigh controlled trials.
Ethics: informed consent should distinguish established care from experimental use, disclose uncertainty and cost, avoid overstated claims, and never substitute research products for medically necessary care.
- Autoimmune flares
What is LL-37 (Cathelicidin)?
In plain words
LL-37 is a peptide [a small protein] found in humans. It can damage bacteria’s outer barriers, affect immune signals, and help skin cells move. Researchers study it for fighting microbes and helping wounds heal, but evidence comes from early research and observations, not proven treatment benefits. It is not FDA-approved; high doses may increase inflammation, and some cancer models suggest it could promote cancer.
Technical definition
LL-37 is a human cathelicidin antimicrobial peptide, also listed as hCAP18 peptide, that disrupts bacterial membranes and has anti-biofilm activity. It modulates Toll-like receptor (TLR) signaling and promotes keratinocyte migration, mechanisms studied for antimicrobial activity and wound healing. It is not FDA-approved and is designated for research use; evidence is preclinical or observational, with risks including pro-inflammatory effects at high doses and potential oncogenicity in some cancer models.
Function
Dosing
Recommended Time of Day
Morning, fasted.
See “Timing & Interactions” below for full fasted/fed circumstances, what to avoid combining, and what pairs well.
Administration & Technique
Injection & Application Sites
- Face / neck (topical) — Clean dry skin, AM and PM, before moisturizer.
Diagram is a general illustration, not a medical instruction. Rotate sites every injection, keep 1 in (2.5 cm) between recent sites, and avoid scars, moles, bruises and the navel area.
Cycling
Not standardized.
Timing & Interactions
- ·Autoimmune flares — may aggravate
- ·Thymosin Alpha-1
Storage & Reconstitution
Reconstitution Calculator
1 mL = 100 units on a standard U-100 insulin syringe. Draw to the nearest 0.5 unit and confirm dosing with a clinician before injection.
Your Notes
Sign in to save personal notes on LL-37 (Cathelicidin) and sync them to Vial Lab.
Benefits
- ·Broad antimicrobial activity
- ·Wound healing in models
- ·Biofilm disruption
Risks
- ·Pro-inflammatory at high doses
- ·Potential oncogenicity in some cancer models
Contraindications
- ·Active malignancy (theoretical)
- ·Pregnancy
- ·Autoimmune disease in active flare (immune activation may worsen symptoms)
- ·Solid-organ or stem-cell transplant recipients on immunosuppression (rejection risk)
- ·Concurrent biologic immunosuppressants or systemic corticosteroids without specialist input
- ·Untreated acute infection requiring standard antimicrobial therapy
- ·Broken, infected, sunburned, or actively inflamed skin
- ·Concurrent prescription retinoid, chemical peel, or laser resurfacing without dermatologic guidance
- ·Known copper sensitivity or Wilson's disease (copper-carrier peptides)
- ·Eczema, rosacea, or perioral dermatitis in active flare
- ·Systemic inflammatory disease such as psoriasis or lupus (LL-37 is an autoantigen)
- ·Not FDA-approved for human therapeutic use — no verified purity, sterility, or potency standards
- ·Immunocompromised or transplant patients (unverified sterility and immunogenicity risk)
- ·Concurrent participation in drug-tested sport (WADA prohibited or non-cleared substance)
- ·Known hypersensitivity or prior reaction to this compound or any excipient/diluent
- ·Pregnancy, attempting conception, or breastfeeding unless prescribed and monitored by a physician
- ·Children and adolescents with open growth plates (unless under specialist endocrine care)
- ·Active or recently treated malignancy without oncology clearance
- ·Use without a confirmed diagnosis, baseline labs, and licensed clinical supervision
Regulatory
Not FDA-approved; research use
Veterinary Use (Pets)
No established veterinary protocol for LL-37 (Cathelicidin). Consult a licensed veterinarian before considering off-label use in any species.
Full veterinary reference →Functional Groups
Cited Works
Tap any study to open the published work.