Healing & repairPeptideEvidence B3 cited

LL-37

Cathelicidin Antimicrobial Peptide

aka Cathelicidin · LL37 · hCAP18 · human cathelicidin antimicrobial peptide

A natural human antimicrobial peptide researched for broad-spectrum microbial defence and wound healing.

Molecular wt

4493g/mol

Formula

C205H340N60O53

CAS

154947-66-7

Half-life

3 h

estimated

Tmax

1 h

PubChem

16198951

Sequence

One-letter37 residues

LLGDFFRKSKEKIGKEFKRIVQRIKDFLRNLVPRTES

Read this before quoting the sequence

37 residues. LL-37 is the mature antimicrobial peptide released from human cathelicidin antimicrobial peptide hCAP18 (UniProt P49913, CAMP_HUMAN); UniProt annotates 'Antibacterial peptide LL-37' as residues 134-170 of the 170-residue precursor, giving exactly this sequence. FDA GSRS registers the same 37-residue subunit under the INN ropocamptide (UNII 3DD771JO2H). Shorter natural fragments (LL-29, LL-23, FF-33, RK-31, KS-30, KR-20) and the 39-residue FALL-39 are distinct species.

Source ↗

Mechanism of action

LL-37 is an antimicrobial peptide that disrupts microbial membranes, leading to cell lysis. It also modulates the immune response by binding to receptors on immune cells, enhancing their activity. Additionally, LL-37 promotes wound healing by stimulating cell proliferation and migration.

What the evidence actually shows

Grade B

There are a few human trials examining LL-37, primarily focusing on its wound healing and antimicrobial properties. These studies suggest potential benefits, but larger, more comprehensive trials are needed to confirm efficacy and safety.

Regulatory status

Status

Not approved in any jurisdiction. No marketing authorisation identified in Drugs@FDA or the EMA medicines register. Developed as a topical wound agent under the INN ropocamptide.

Clinical stage

Phase 2b completed for topical treatment of hard-to-heal venous leg ulcers (HEAL LL-37); no approval.

WADA

Not named on the 2026 WADA Prohibited List. Note S2 also captures 'other substances with similar chemical structure or similar biological effect(s)'.

research_compound

In the UK, LL-37 is considered a research compound and is not approved for clinical use by the MHRA.

Source ↗

Pharmacokinetics

Half-life

3 h

Tmax

1 h

Absorption

subcutaneous

Elimination

renal

Washout

2 days

Low-confidence pharmacokinetics

These figures are recorded as estimated rather than measured in a published PK study. Treat them as an order of magnitude. Anything downstream of them — accumulation, steady state, washout — inherits that uncertainty.

Dosing — what backs each figure

LL-37 has genuine human trial dosing, but exclusively as a topical wound treatment: 0.5-3.2 mg/mL applied twice weekly for four weeks in venous leg ulcers across a first-in-man study and a 148-patient phase IIb, the latter missing its primary endpoint. Notably the highest concentration (3.2 mg/mL) performed no better than placebo, so higher is not better. No systemic or injected LL-37 dosing has been established in humans.

ClinicalApproved labelling or a published human trial

Topical LL-37 at 0.5, 1.6 or 3.2 mg/mL, or placebo, applied twice weekly for 4 weeks, following a 3-week open-label placebo run-in and followed by 4 weeks of follow-up. Healing rate constants for 0.5 and 1.6 mg/mL were ~6-fold and ~3-fold higher than placebo; 3.2 mg/mL showed no benefit over placebo
34 participants with hard-to-heal venous leg ulcers (first-in-man randomised, placebo-controlled trial) · topical (applied to the wound)
Gronberg A et al. Treatment with LL-37 is safe and effective in enhancing healing of hard-to-heal venous leg ulcers: a randomized, placebo-controlled clinical trial. Wound Repair Regen. 2014;22(5):613-21 ↗
Topical LL-37 at 0.5 mg/mL or 1.6 mg/mL versus placebo, in combination with compression therapy (HEAL LL-37 phase IIb). The trial did not meet its primary efficacy endpoint in the full study population; a post hoc subgroup with wounds >=10 cm2 showed improvement
148 patients with hard-to-heal venous leg ulcers, mean age 67.6 years, median ulcer duration 20.3 months · topical
Mahlapuu M et al. Evaluation of LL-37 in healing of hard-to-heal venous leg ulcers: a multicentric prospective randomized placebo-controlled clinical trial. Wound Repair Regen. 2021;29(6):938-950 ↗

Commonly circulatedNot established by any study

Dose: Research literature cites low microgram-range research use
Frequency: Daily/EOD

Why this isn't evidence
Human LL-37 dosing is expressed as a topical concentration applied to a wound (0.5-3.2 mg/mL, twice weekly for 4 weeks), not as a 'low microgram-range' systemic dose given daily or every other day, so the ported dose unit, route and frequency all diverge from the only published human regimens.

This figure is shown because it is what circulates and what people search for — not because it is supported. Cycle lengths in particular tend to be convention copied between compounds rather than anything derived from a compound's own pharmacokinetics.

No established human dose

No approved label or completed human trial establishes a dosing regimen for this compound. Anything presented as a standard protocol for it — anywhere — is someone's convention rather than a finding.

Handling and storage

No compound-specific stability data exists

No compound-specific published stability data (temperature/duration for lyophilised or reconstituted material, light sensitivity, freeze-thaw tolerance) was located in any regulatory label, pharmacopoeial monograph or peer-reviewed source. Only generic lyophilised-peptide handling guidance exists, and generic guidance is not compound-specific; no specific figures are asserted here. LL-37 has no approved product. The clinical development compound (ropocamptide) was a topical formulation given at 0.5, 1.6 and 3.2 mg/mL, but the published trial reports do not state storage or stability conditions. General peptide handling still applies — reconstitute gently, keep it cold, keep it dark — but any specific figure you see quoted for this compound elsewhere is someone's assumption, not a measurement.

→ Reconstitution walkthrough → Reconstitution calculator

Safety

Commonly reported

·Mild local irritation

Rarely reported

·Severe allergic reactions

Contraindications

·Known hypersensitivity to LL-37

Limited human data; injection-site reactions

Reported combinations

Reported as synergistic

·Vitamin C

Combination claims in this dataset are largely unsourced and should be treated as folk knowledge until a citation appears beside them.

References (3)

Gronberg A, Mahlapuu M, Stahle M, Whately-Smith C, Rollman O (2014) Treatment with LL-37 is safe and effective in enhancing healing of hard-to-heal venous leg ulcers: a randomized, placebo-controlled clinical trial ↗
Wound Repair and RegenerationPMID 25041740DOI
First-in-man trial in 34 patients: 4-week randomised double-blind phase with twice-weekly topical LL-37 at 0.5, 1.6 or 3.2 mg/mL or placebo; healing rate constants for 0.5 and 1.6 mg/mL were about sixfold and threefold higher than placebo, with no benefit at 3.2 mg/mL.
Mahlapuu M, Sidorowicz A, Mikosinski J, Krzyzanowski M, Orleanski W, Twardowska-Saucha K, Nykaza A, Dyaczynski M, Belz-Lagoda B, Dziwiszek G, Kujath P, Bara C, Schulze A, Krolicki A, Nilsson A, Sjoberg F, Wegener A, Kristensen J, Bjornsson A, Kjaerulff S, Nielsen C, Bratt H (2021) Evaluation of LL-37 in healing of hard-to-heal venous leg ulcers: A multicentric prospective randomized placebo-controlled clinical trial ↗
Wound Repair and RegenerationPMID 34687253DOI
HEAL LL-37 phase IIb double-blind randomised placebo-controlled trial in 148 patients with hard-to-heal venous leg ulcers, testing topical LL-37 at 0.5 or 1.6 mg/mL alongside compression therapy.
Fabisiak A, Murawska N, Fichna J (2016) LL-37: Cathelicidin-related antimicrobial peptide with pleiotropic activity ↗
Pharmacological ReportsPMID 27117377DOI
Review of LL-37's antimicrobial, immunomodulatory, chemotactic, angiogenic and wound-healing activities and its dual pro- and anti-inflammatory roles.

Data provenance

Chemistry and citations on this page were checked against primary sources on 2026-08-14. Values that could not be verified were left blank rather than filled with a plausible guess.

Could not verify
sequence.threeLetter, storage.lyophilized, storage.reconstituted, storage.lightSensitive, reconstitution.solvent

Research use only

This profile is educational reference material. It is not medical advice, not a prescription, and not an endorsement of self-administration. Compounds discussed here are research chemicals and most are not approved for human therapeutic use.

Related in Healing & repair

BPC-157

A synthetic pentadecapeptide derived from a protein found in gastric juice. Studied for tissue repair, tendon/ligament healing, and gut protection in preclinical models.

BPC-157 Arginate

BPC-157 Arginate is the arginine salt form of Body Protection Compound 157, a synthetic pentadecapeptide derived from a partial sequence of human gastric juice protein. This formulation pairs the BPC-157 peptide with arginine as a counter-ion, which proponents claim provides improved stability and enhanced oral bioavailability compared to the standard acetate salt form. The underlying peptide consists of 15 amino acids and has demonstrated cytoprotective, anti-inflammatory, and tissue-healing properties across numerous preclinical studies. It promotes angiogenesis, modulates nitric oxide pathways, and upregulates growth factor expression. The arginate form is marketed as offering better gastric survival and systemic absorption when taken orally, though direct head-to-head comparative data remains limited.

GV1001

A 16-amino acid peptide derived from the active site of human telomerase reverse transcriptase (hTERT). Originally developed as a cancer immunotherapy vaccine, now investigated for anti-inflammatory and anti-aging properties.