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Immunepreclinical

LL-37

Cathelicidin LL-37
Immune · CAS 154947-66-7
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Category
Immune
Evidence grade
D
PubMed records
2,527
Female-tagged
501
Sex-analysis
2
CAS
154947-66-7
D
Evidence grade D, Preclinical / animal evidence only across 2527 indexed studies. No human trial data. How grades work →
Female evidence: None
LL-37: of 2,527 PubMed records, 501 are tagged as including female subjects and 2 carry a sex-analysis tag.Counts reflect PubMed records as of 2026-07-21. “Female” uses the Female MeSH filter and “sex-analysis” the Sex Factors MeSH filter, automated proxies pending manual study-level review. Methodology →

Overview

LL-37 is the only human cathelicidin-derived antimicrobial peptide, a 37-residue sequence released from its precursor protein as part of the innate immune system. Its amphipathic structure gives it a research-friendly profile as a tool compound for studying host-defense peptides and their interactions with microbial membranes.

In vitro and in preclinical systems, LL-37 has been studied for its membrane-interacting antimicrobial activity, its immunomodulatory and chemotactic signaling on immune cells, and its role in wound-environment models. Researchers examining innate immunity have used it as a research material to probe interactions with bacterial membranes, biofilm formation, and Toll-like receptor signaling.

What makes LL-37 notable for an immune catalog is its status as the singular human cathelicidin, which anchors a large body of host-defense literature. Whether these mechanisms translate to female physiology remains an open research question; our evidence review tracks how many of the underlying studies included women.

Summary

LL-37 is the only human cathelicidin antimicrobial peptide, studied mainly as an endogenous molecule in skin, airway, and immune conditions rather than as an administered drug. Almost all evidence is preclinical or observational, with no established therapeutic regimen and no female-specific clinical data, despite women being over-represented in several autoimmune and dermatologic conditions where LL-37 is measured.

Evidence in women

Menstrual cycle
Unstudied
Endogenous LL-37 varies with skin and mucosal states, but no study relates administered LL-37 to the menstrual cycle.
Pregnancy & lactation
Unstudied
No safety data for administered LL-37 in pregnancy or lactation.
Hormonal interactions
Unstudied
No data on estrogen, thyroid, or contraceptive interactions with therapeutic LL-37.
Perimenopause & menopause
Unstudied
No perimenopausal or menopausal therapeutic data.
Sex differences
Unstudied
Observational studies measure endogenous LL-37 in women, but no controlled study evaluates a sex difference in response to administered LL-37.

Mechanism

A cationic, amphipathic peptide that disrupts microbial membranes and modulates host immune signaling, chemotaxis, and wound repair.

Reported dosing & routes

◐

We don't give dosing or medical advice. The figures below describe what was used in published research, not a recommendation. Decide with your clinician.

Reported range (literature)No established human therapeutic dose; studied endogenously and in preclinical models.
Routestopical, intravenous
Female-specific dosingNot established

Contraindications: insufficient human data to characterize

Side effects

Reported in the research literature. Sex-specific incidence has not been separately analysed in the available records.

cytotoxicity to host cells at high concentrations (preclinical)

LL-37 reconstitution calculator

Enter this vial's amount, the bacteriostatic water you add, and a target amount to get the concentration and the U-100 syringe units to draw. Handling arithmetic for research use, not a dose recommendation.

Reconstitution

1
2
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Draw for LL-37

5
units on a U-100 insulin syringe
020406080100
U-100 insulin syringe — 1 mL = 100 units
That's 0.05 mL drawn to the 5-unit mark.
Concentration5 mg/mL (5,000 mcg/mL)
Volume to draw0.05 mL
Doses per vial40

Reference chart at 5 mg/mL

Target amountVolume (mL)U-100 units
100 mcg0.02 mL2
250 mcg0.05 mL5
500 mcg0.1 mL10
750 mcg0.15 mL15
1000 mcg0.2 mL20

Research-use arithmetic only. This tool converts a vial amount, diluent volume, and a target amount into a concentration and syringe draw for laboratory handling. It is not dosing guidance, a recommendation, or a claim of safety or efficacy, and it does not account for overfill, dead space, or peptide purity. Nothing here is medical advice. “U-100” means 100 units = 1 mL; confirm your syringe graduation before measuring. See the reconstitution & storage handbook for handling detail.

Frequently asked questions

Answers drawn only from LL-37's research facts and, where reviewed, its sex-disaggregated evidence. Nothing here is medical advice, dosing, or a claim of safety or efficacy.

What is LL-37?

LL-37, also known as Cathelicidin LL-37, is a research compound in our immune category. LL-37 is the only human cathelicidin antimicrobial peptide, studied mainly as an endogenous molecule in skin, airway, and immune conditions rather than as an administered drug.

Is LL-37 studied in women?

LL-37: of 2,527 PubMed records, 501 are tagged as including female subjects and 2 carry a sex-analysis tag. We grade this none: no PubMed record for LL-37 is tagged as including female subjects, so its effects in women are effectively unstudied. That blank is the finding, not a safety signal, and we do not fill it with guesses.

Has LL-37 been studied during pregnancy or breastfeeding?

Unstudied. No safety data for administered LL-37 in pregnancy or lactation. This is not a safety clearance or a recommendation. Vera, our research chat, deliberately hard-stops on pregnancy, breastfeeding, and trying-to-conceive questions rather than answer them.

What evidence grade does LL-37 have, and why?

LL-37 carries evidence grade D. Preclinical / animal evidence only across 2527 indexed studies. No human trial data.. Grades are derived from the research record, never hand-assigned; see how grades work.

Is there a female-specific dose for LL-37?

No. A female-specific dose for LL-37 is not established, and this site does not provide dosing or medical advice. Any figures we show describe what published research used, not a recommendation. Decide anything about use with a qualified clinician.

How is LL-37 administered in research?

In the published literature, LL-37 is administered via topical, intravenous. Reported dose ranges on the Dosing tab describe what studies used for laboratory research, not a protocol for people. We don't provide dosing.

What side effects have been reported for LL-37?

Effects reported in the research literature include cytotoxicity to host cells at high concentrations (preclinical). Sex-specific incidence has not been separately analysed in the available records, so these are not broken out for women.

What is the CAS number for LL-37?

The CAS registry number for LL-37 is 154947-66-7. It is also referred to as Cathelicidin LL-37, hCAP-18, Cathelicidin antimicrobial peptide. Use it to confirm identity against a Certificate of Analysis.

How should LL-37 be stored and handled?

LL-37 sold for research is supplied as a lyophilized (freeze-dried) powder. Lyophilized peptides are generally kept cold and dry, at roughly -20°C for longer-term storage and 2-8°C short-term, protected from light. Once reconstituted they are typically refrigerated and used within a short window, avoiding repeated freeze-thaw cycles. This is general laboratory handling for research use only, not a directive for human use. Always follow the handling and purity details on the product's Certificate of Analysis.

Where can I buy LL-37 for research?

For laboratory research use, LL-37 is available from our research-use partner, Aurevena Research. Applying code research15 takes 15% off. We may earn a commission when you purchase through this link, at no extra cost to you. Products are for laboratory research use only.

Buy LL-37 at Aurevena Research
Research-use supplier: LL-37 is available from our research-use vendor for laboratory use. Code research15 for 15% off, applied automatically at checkout. We may earn a commission when you purchase through this link, at no extra cost to you. Products are for laboratory research use only.
Buy now →

Citations (PMID)

36781570 · 32947991 · 35625823

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Educational information for laboratory and research use only. Not medical advice, a recommendation, or a claim of safety or efficacy; no personal dosing. “Unstudied” means no qualifying study was found, not that a compound is safe or unsafe.