Peptide guide · Immune / Inflammation

LL-37: the evidence, status, and research questions.

LL-37 guide to human and preclinical evidence, research uses, FDA status, sport status, primary sources, and key limits.

01What is LL-37?02What is the evidence for LL-37?03What is LL-37 being studied for?04Is LL-37 FDA approved?05Is LL-37 prohibited in sport?06What are the evidence limits for LL-37?

EVIDENCE TAKEAWAY

The short answer.

LL-37 is an important endogenous host-defense peptide, but complex pro-inflammatory, anti-inflammatory, antimicrobial, and cytotoxic actions make simple immune-support claims misleading.

WHAT IS LL-37?

Start with identity.

A human antimicrobial peptide involved in innate immune signaling and host defense.

Entity type
Native peptide
Research category
Immune / Inflammation
Names and aliases
LL-37

HUMAN VS PRECLINICAL

What evidence exists for LL-37?

HUMAN EVIDENCE
1/5 · No established therapeutic program

The human peptide is well characterized biologically, but a reliable clinical efficacy program for marketed LL-37 products was not identified.

PRECLINICAL EVIDENCE
4/5 · Extensive innate-immune research

Antimicrobial, inflammatory, and cytotoxic effects are extensively studied in laboratory systems.

RESEARCH INTENT

What is LL-37 being studied for?

Current source-backed research areas include the topics below. Inclusion means the area is being investigated; it does not establish a treatment benefit.

  • 01Antimicrobial defense
  • 02Innate immunity
  • 03Inflammation
  • 04Cytotoxicity

U.S. REGULATORY STATUS

Is LL-37 FDA approved?

No FDA-approved LL-37 drug product; FDA reports insufficient human safety information for compounded LL-37 products.

SPORT STATUS

Is LL-37 prohibited in sport?

Not specifically named in the 2026 WADA List; athletes should verify current status and product contents.

Anti-doping rules and product ingredients can change. Athletes should verify the current official list and the exact product before making a real decision.

EVIDENCE LIMITS

What can the current record not establish?

COMMON SEARCH INTENTS

Reviewed questions about LL-37.

PRIMARY AND OFFICIAL SOURCES

Inspect the research behind this guide.