Antimicrobial / Immune Research Peptides Guide

This guide covers 9 research peptides in the Antimicrobial / Immune category. Each compound is evaluated on its evidence base, mechanism, safety profile, and current clinical status.

Evidence: D | Status: Investigational / Limited clinical trial data (topical wound healing RCT exists)

LL-37 is the only human cathelicidin antimicrobial peptide, a 37-amino-acid cationic peptide (sequence: LLGDFFRKSKEKIGKEFKRIVQRIKDFLRNLVPRTES) with broad-spectrum antimicrobial activity against Gram-positive and Gram-negative bacteria, fungi,...

Use cases: Immune Support, Antimicrobial

Evidence: D | Status: Endogenous peptides. No therapeutic product in clinical development. Studied as biomarkers and templates for antimicrobial drug design.

Beta-defensins are a family of small cationic antimicrobial peptides (36-45 amino acids, MW ~4-5 kDa) produced by epithelial cells throughout the body.

Use cases: Immune Support, Antimicrobial Research

Evidence: D | Status: Endogenous peptides. No therapeutic product in clinical development. Studied as biomarkers (e.g., synovial fluid alpha-defensin test for periprosthetic joint infection).

Alpha-defensins are a family of small cationic antimicrobial peptides (29-35 amino acids, MW ~3.5-4.5 kDa) with three characteristic intramolecular disulfide bonds.

Use cases: Immune Support, Antimicrobial Research, Diagnostics

Evidence: D | Status: Preclinical research only. No clinical trials registered for lactoferricin as a standalone therapeutic.

Lactoferricin is a 25-amino-acid antimicrobial peptide (f17-41 of bovine lactoferrin; MW ~3126 g/mol for bovine form) generated by pepsin digestion of lactoferrin.

Use cases: Antimicrobial Research, Immune Support

Evidence: D | Status: Preclinical. Bee venom therapy (apitherapy) is used in traditional medicine. No approved pharmaceutical product based on isolated melittin.

Melittin is a 26-amino-acid cationic amphipathic peptide (sequence: GIGAVLKVLTTGLPALISWIKRKRQQ, MW ~2846 g/mol) that constitutes approximately 40-60% of dry honeybee (Apis mellifera) venom.

Use cases: Antimicrobial Research, Anticancer Research

Evidence: D | Status: Endogenous peptide. No therapeutic product in development. Studied as a template for antifungal drug design.

Histatin-5 is a 24-amino-acid histidine-rich cationic peptide (sequence: DSHAKRHHGYKRKFHEKHHSHRGY, MW ~3036 g/mol) found in human saliva.

Use cases: Antimicrobial Research, Oral Health

Evidence: C | Status: Phase III completed. Two NDA submissions to FDA (1999 and 2016) — both unsuccessful. Not approved in any jurisdiction.

Pexiganan (MSI-78) is a 22-amino-acid synthetic analog of magainin 2, an antimicrobial peptide originally isolated from the skin of the African clawed frog (Xenopus laevis).

Use cases: Antimicrobial Research, Wound Care

Evidence: C | Status: Phase III completed for catheter infections (not approved, 2003). Phase III for rosacea (CLS001 by Cutanea Life Sciences, results ~2018). No regulatory approval.

Omiganan (MBI 226) is a 12-amino-acid synthetic cationic antimicrobial peptide (sequence: ILRWPWWPWRRK-NH2, MW ~1779 g/mol) derived from indolicidin, a natural antimicrobial peptide from bovine neutrophils.

Use cases: Antimicrobial Research, Dermatology

Evidence: C | Status: Phase II completed for ABSSSI (positive results). Phase II for oral mucositis. Investigated for COVID-19 (in vitro). No Phase III initiated.

Brilacidin (PMX-30063) is a synthetic small-molecule defensin-mimetic (MW ~564 g/mol) developed by Innovation Pharmaceuticals (formerly Cellceutix).

Use cases: Antimicrobial Research, Anti-Infective Development