For research use only. Not for human consumption. Not medical advice — consult a licensed clinician.

Immune Modulator

LL-37

Also known as: Cathelicidin

LL-37 is the only human cathelicidin antimicrobial peptide — a 37-amino-acid peptide (starting with two leucines) cleaved from the hCAP-18 precursor. It has broad-spectrum antimicrobial activity and immunomodulatory roles, but is also implicated in the pathogenesis of autoimmune and inflammatory skin diseases including psoriasis, rosacea, and lupus. Not FDA-approved; research-use only.

Where to buy · live market data

Who's worth your money for LL-37

Every current seller, ranked by independent evidence — Merit Score, latest COA purity, and live $/mg (size-normalized). Prices refresh daily. Rankings are never paid.

Top Merit pick

🇺🇸 Glacier Aminos 99

Highest Merit Score (99) of 20 scored sellers

$7.00/mg

$34.99 · 5mg · 99.0% purity

1 COA
Buy Code MERIT · 10% off

Best value after code

🇺🇸 Southern Aminos 82

$2.76/mg effective with 15% code

$3.25/mg

$32.45 · 10mg · 99.8% purity

1 COA
Buy Code MERIT · 15% off

Most tested

🇺🇸 Verified Peptides 86

8 independent COAs on file

$13.00/mg

$65.00 · 5mg · 99.8% purity

8 COAs
Buy

Average price

$10.76/mg

Sellers

45

45-day trend

-23.7%

32 of 45 sellers have a current price· 4 stale hidden· 8 unverified hidden

Prices observed from public storefronts (last 24h), normalized to $/mg. "Evidence" is Merit's 0–100 Merit Score, derived only from observable verification evidence (methodology on /about); "Purity" is the latest independent COA. Some buy links are affiliate links — Merit may earn a commission at no extra cost to you, and where a vendor offers one, the code shown gets you a discount at their checkout. Affiliate status never affects price data, ranking, or the Merit Score (full policy on /disclosure). Research use only.

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Compound reference

About LL-37

CAS

154947-66-7

Molecular formula

C205H340N60O53

Sequence

LLGDFFRKSKEKIGKEFKRIVQRIKDFLRNLVPRTES

Typical dose range

100–400 mcg/day subcutaneous

Half-life

~4–6 hours (tissue-dependent; limited formal PK data for native LL-37)

Independent evidence

COAs for LL-37

59 third-party tests across 20 vendors. Each card links to the full report.

All 59 COAs for LL-37 →
Measured purity 91.1%–100.0% across 48 COAs
Measured purity over time
Aggregated · 3rd-party listing
99.38 %
Sep 2026
Janoshik Analytical Limited

For

LL-37

by CertaPeptides· batch CP-2608-LLT5

✓ Vendor-published
99.31 %
Sep 2026
Chromate Moderate

For

LL-37

by Ruo Bio· batch LL3-H-003

COA on file
Aggregated · 3rd-party listing
99.00 %
Sep 2026
Ethos Analytics Strong

For

LL-37

by Glacier Aminos· batch LL5GA-01

✓ Vendor-published
99.81 %
Aug 2026
Janoshik Analytical Limited

For

LL-37

by Verified Peptides· batch LL0526030C

COA on file
Aggregated · 3rd-party listing
99.65 %
Jul 2026
Freedom Diagnostics Moderate

For

LL-37

by Peptide Plugs· batch 175-01-DK

Aggregated · 3rd-party listing
99.60 %
Jun 2026
ILS Labs Strong

For

LL-37

by Ion Peptide· batch L375-06092026

✓ Vendor-published
99.83 %
Jun 2026
ILS Laboratories

For

LL-37

by Ion Peptide· batch L375-06092026

COA on file
Aggregated · 3rd-party listing
99.64 %
May 2026
Janoshik Analytical Limited · HPLC

For

LL-37

by Verified Peptides· batch LL05260305C

✓ Vendor-published
99.64 %
May 2026
Janoshik Analytical Limited

For

LL-37

by Verified Peptides· batch LL05260305C

COA on file
Aggregated · 3rd-party listing
99.64 %
May 2026
Janoshik Analytical Limited

For

LL-37

by Verified Peptides

Aggregated · 3rd-party listing
94.08 %
May 2026
Janoshik Analytical Limited

For

LL-37

by Verified Peptides· batch LL025602005C

Aggregated · 3rd-party listing
91.08 %
May 2026
Freedom Diagnostics Moderate

For

LL-37

by Real Peptides· batch Black Cap

Aggregated · 3rd-party listing
99.94 %
Mar 2026
Kovera Labs

For

LL-37

by Ion Peptide· batch LL375-03232026

✓ Vendor-published
99.94 %
Mar 2026
Kovera Labs

For

LL-37

by Ion Peptide· batch LL375-03232026

COA on file
Aggregated · 3rd-party listing
99.96 %
Mar 2026
Freedom Diagnostics Moderate

For

LL-37

by Modern Research Peptides· batch GCEMHK0226

Aggregated · 3rd-party listing
99.50 %
Feb 2026
Janoshik Analytical Limited

For

LL-37

by EZ Peptides· batch EZP-LL371002172026-01

✓ Vendor-published
99.50 %
Feb 2026
Janoshik Analytical Limited

For

LL-37

by EZ Peptides· batch EZP-LL37100217-2026-01

COA on file
Aggregated · 3rd-party listing
99.47 %
Feb 2026
Vanguard Laboratory Strong

For

LL-37

by Peptidology· batch 1669

✓ Vendor-published
99.93 %
Jan 2026
Freedom Diagnostics Moderate

For

LL-37

by Alpha Omega· batch LL05-0116206J-1

COA on file
✓ Vendor-published
99.04 %
Jan 2026
Janoshik Analytical Limited

For

LL-37

by Ruo Bio

COA on file
Aggregated · 3rd-party listing
99.93 %
Jan 2026
Freedom Diagnostics Moderate · HPLC

For

LL-37

by Simple Peptide· batch L1-05-01162026-J

✓ Vendor-published
99.93 %
Jan 2026
Freedom Diagnostics Moderate

For

LL-37

by Alpha Omega· batch LL10-370112326-1

COA on file
Aggregated · 3rd-party listing
99.83 %
Jan 2026
Freedom Diagnostics Moderate

For

LL-37

by Southern Aminos· batch LL050126A

Aggregated · 3rd-party listing
99.93 %
Jan 2026
Freedom Diagnostics Moderate · HPLC

For

LL-37

by Simple Peptide· batch LL10-37011220236-J

Research depth

20 citations indexed for LL-37

All research on LL-37 →

review · 2026

Apoptosis Modulation by LL-37: From Mitochondrial Cell Death to Prosurvival Signaling

This review summarizes current knowledge on the role of human cathelicidin LL-37 in the regulation of apoptosis. LL-37 can modulate programmed cell death pathways, exerting either proapoptotic or antiapoptotic effects depending on various factors, such as cell type and peptide concentration.

review · 2026

LL-37-MRGPRX2-Mast Cell Signaling in Rosacea: Current Evidence and Directions for Human Studies

This critical narrative review examines evidence relevant to LL-37-Mas-related G protein-coupled receptor X2 (MRGPRX2)-mast-cell signaling in rosacea and considers the relevance of these findings to future human studies.

Study · 2026

Coordination chemistry and antimicrobial activity of LL-37, its C-terminal fragment, and a peptidomimetic analogue

Human cathelicidin LL-37 is an antimicrobial peptide naturally present in saliva that plays an important role in host defence against bacterial and fungal pathogens. Although LL-37 is known to bind Cu(II) and Zn(II) ions, the corresponding coordination modes have remained unresolved.

review · 2026

LL-37-based oral antimicrobial therapeutics: translational challenges and future directions-a narrative review

LL-37 is an antimicrobial peptide involved in antimicrobial defence, inflammatory regulation, tissue repair, and bone regeneration in the oral cavity. Salivary and gingival crevicular fluid LL-37 levels are associated with disease activity and treatment responses.

review · 2026

LL-37: Biological Mechanisms and Emerging Therapeutic Applications in Intestinal Disease

Human cathelicidin peptide LL-37 is encoded by the CAMP gene and plays a key role in innate immunity. It maintains intestinal homeostasis through antibacterial, immunomodulation, and tissue repair functions.

Study · 2026

LL-37 and citrullinated-LL-37 enhances oxylipins: citrullination attenuates LL-37-mediated COX-2-dependent chemokine response in human bronchial epithelial cells

BACKGROUND: During airway inflammation, chemokines, oxylipins (bioactive lipids) and cationic host defence peptides (CHDP) are enhanced in the lungs. However, the interplay of these molecules in the process of airway inflammation is not fully resolved.