Peptide field guide
HNP1
HNP1 (human neutrophil peptide 1) is an alpha-defensin antimicrobial peptide produced by neutrophils and studied for membrane-active antibacterial effects and synergy with other innate peptides.
What it is
HNP1 (human neutrophil peptide 1) is a human alpha-defensin antimicrobial peptide produced by neutrophils. It’s part of innate immune defense and is studied for how it damages microbial membranes and modulates immune responses.
Why people care about it
HNP1 is frequently discussed as part of a broader theme: the body’s own peptides can act as both weapons and signals.
It’s also a useful example of how combining peptides can sometimes improve outcomes, for example increasing antibacterial effects while reducing toxicity.
What we know vs what we don’t know
What we know:
- HNP1 is a well-studied human defensin with antimicrobial activity.
- Pairing HNP1 with LL‑37 has been reported to produce “double cooperativity” effects in mechanistic studies.
What we don’t know:
- How (or whether) these innate peptide effects can be translated into safe therapeutics.
Latest updates
- 2026-04-02: A mechanistic study proposed that LL‑37 and HNP1 form reversible aggregates whose aggregation state depends on membrane lipid composition, helping explain improved antibacterial effects with reduced cytotoxicity in combination. https://pubmed.ncbi.nlm.nih.gov/41923698/
Safety reality
HNP1 is not an approved drug. Treat any non-regulated products claiming to be HNP1 as high risk.