Evidence strength for the context described on this page.
PEPTIDE ATLAS / IMMUNE & GUT / LL-37
Not FDA-approvedPreclinical
LL-37
ALSO KNOWN ASCathelicidin LL-37
An endogenous antimicrobial peptide with complex immune and tumor biology—not a general infection defense.
01CATEGORYImmune & gut
02REGULATORY STATUSNot FDA-approved
03COMMON ROUTETopical in human wound trials; systemic injection is marketed but unapproved and lacks human trials
04DOSE BASISTopical human study + reported systemic use
HOW TO USE THIS PAGE
Read the profile in the order that protects the decision.
- 01Verify what it is
Confirm the exact molecule, route, regulatory lane and actual human evidence.
- 02Read limits before dose
Unsupported claims, contraindications and uncertainty come before any protocol.
- 03Build the monitoring plan
Define the target, baseline checks, reassessment point and stop rules with a qualified clinician.
This peptide does not have an FDA-approved product or dose for the claims described here. Research dosing and vendor protocols are not consumer prescribing guidance.
RESEARCH PASSPORT
The five facts to know first.
REVIEWED
JULY 2026
Status is product-, formulation- and indication-specific.
Trial, label or reported-practice basis is always named.
Official labels, regulators, trials and indexed literature where available.
Peptide hormones, growth factors and related substances may be prohibited.
Check Global DRO ↗OVERVIEW
What LL-37 is.
A human cathelicidin involved in innate immunity, antimicrobial defense and inflammation. Endogenous biology does not make systemic supplementation safe.
HOW IT IS THOUGHT TO WORK
Interacts with microbial membranes and multiple host signaling pathways; effects can be antimicrobial, inflammatory, reparative or harmful depending on tissue and context.
EFFECTS & EVIDENCE
What the evidence supports—and what it does not.
- Important endogenous immune biology
- No established consumer treatment for infection, wounds or immune resilience
- Chronic-infection treatment
- Biofilm eradication in people
- General immune enhancement
- Safe injectable use
Evidence grade: Preclinical. For an approved drug, “high” refers only to its labeled indication—not every off-label or wellness claim.
DOSAGE CONTEXT
Best available dosing range.
Topical human study + reported systemic useBest human dose evidence is topical: venous-leg-ulcer trials applied 0.5 or 1.6 mg/mL twice weekly for 4 weeks; 3.2 mg/mL caused more local reactions. Reported systemic clinic/community protocols range from about 100–500 mcg subcutaneously daily to 50 mcg/kg daily, but no injectable human trial validates them. The topical study cannot be converted into an FDA-approved systemic dose.
BEST AVAILABLE GENERIC RANGE
Men and women.
The basis is named above. Reported-use ranges describe what clinics or communities publish; they are not proof of safety, efficacy, legality or product quality.
- Schedule in that source context
- Topical trial: twice weekly for 4 weeks with compression care. Reported systemic cycles often run 4–8 weeks, but no injectable human trial establishes a schedule.
- How to interpret it
- Route must stay explicit. Topical wound concentrations cannot be converted into an injection. FDA notes insufficient systemic safety information and a nonclinical male-reproductive signal.
ACTUAL HUMAN DOSES REPORTED IN THE RECORD
Research regimens may use different routes, diagnoses, formulations and monitoring. They cannot automatically be converted into a general protocol.
- Phase 1/2 venous-leg-ulcer study: topical 0.5, 1.6 or 3.2 mg/mL LL-37 twice weekly for 4 weeks; lower concentrations were better tolerated and showed the clearest healing signal.
- Phase 2b topical follow-up evaluated LL-37 in hard-to-heal venous leg ulcers; this remains investigational wound treatment, not systemic immune dosing.
- Route
- Topical in human wound trials; systemic injection is marketed but unapproved and lacks human trials
- Duration
- Topical human study: 4 weeks; reported systemic cycles: 4–8 weeks
- Men & women
- No validated systemic sex-specific dose. FDA notes a nonclinical male-reproduction concern, and pregnancy safety is unknown.
Clinician verification required. Always double-check the exact molecule or salt, concentration, route, volume, schedule, indication, patient-specific contraindications, interactions and applicable law with the prescribing clinician and dispensing pharmacy. A disclaimer does not make an unapproved product FDA-approved, and a reported-use range is not a prescription.
MONITORING
What should be tracked.
- Suspected infection requires organism- and site-specific diagnosis
- No biomarker makes unapproved systemic use safe
SAFETY
Risks, red flags and reasons to avoid it.
- FDA cites insufficient safety information
- Nonclinical findings suggest possible detrimental male reproductive effects
- May be protumorigenic in some tissues
- Immunogenicity, impurities and sterility risk
- Human injection
- Active cancer
- Fertility attempts
- Replacing antibiotics or wound care
Stop and seek careGet urgent medical help for trouble breathing, facial or throat swelling, chest pain, fainting, severe persistent abdominal pain, neurologic changes, severe hypoglycemia, uncontrolled vomiting or a prolonged painful erection.
CLINICIAN VISIT CHECKLIST
Six questions worth bringing with you.
Molecule or analog, salt, concentration, route, manufacturer or compounder, lot and beyond-use date.
Name the diagnosis or target, how it will be measured and the realistic time to reassess.
Ask how it compares with FDA-approved, lower-risk or better-studied alternatives.
Label, human trial, specialty guideline or clinic convention—and whether that route and formulation match.
Baseline checks, follow-up measures, interactions, pregnancy considerations and symptoms that mean stop.
Pharmacy license, prescription, identity/potency testing, sterility controls and who handles a product complaint.
Do not improvise reconstitution or convert “units” without the exact concentration. Mixing, storage and beyond-use instructions are product-specific; confirm them with the dispensing pharmacy.
PRIMARY SOURCES
Read the record yourself.
We prioritize official prescribing information, FDA regulatory material, registered trials and indexed biomedical literature. A source supports the specific statement beside it—not every claim made about the molecule.
PRODUCTS & TREATMENT ACCESS
There is no product we can responsibly recommend.
Research-chemical and some compounded marketing; not FDA-approved.
Antimicrobial activity in a laboratory does not mean a peptide safely reaches an infection—or improves outcomes—in a person.
Evidence before affiliate revenue.
We do not rank or sell unapproved research peptides. Use the Atlas to discuss safer, evidence-backed alternatives with a qualified clinician.
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