Defensins
Antimicrobial PeptideresearchAlso known as: Human Beta-Defensins, HBD, Human Neutrophil Peptides, HNP, Alpha-Defensins, Beta-Defensins
A family of small cationic antimicrobial peptides that form a critical part of the innate immune system, providing broad-spectrum defense against bacteria, fungi, and viruses.
Overview
Defensins are a family of small (29-45 amino acids), cysteine-rich cationic peptides that play a fundamental role in innate immunity. They are divided into alpha-defensins (HNP-1 through HNP-4, HD-5, HD-6) found primarily in neutrophils and intestinal Paneth cells, and beta-defensins (HBD-1 through HBD-4) produced by epithelial cells of the skin, respiratory tract, and urogenital tract. Defensins kill microbes by disrupting their cell membranes through electrostatic interactions with negatively charged microbial surfaces. Beyond direct antimicrobial activity, defensins serve as chemoattractants for immune cells, bridge innate and adaptive immunity, and promote wound healing. In the peptide community, defensins are of interest for their potential to enhance immune resilience and combat biofilm-forming infections.
Mechanism of Action
Defensins exert antimicrobial effects through: (1) Electrostatic attraction to negatively charged microbial membranes, followed by membrane pore formation and disruption; (2) Inhibition of bacterial cell wall synthesis; (3) Chemoattraction of dendritic cells, T-cells, and monocytes to sites of infection; (4) Activation of complement pathways; (5) Neutralization of bacterial toxins and endotoxins; (6) Enhancement of phagocytosis by macrophages; (7) Modulation of inflammatory cytokine production. Beta-defensins also stimulate keratinocyte migration and proliferation for wound healing.
Molecular Formula
Varies by defensin subtype
Molecular Weight
3500-4500 g/mol (varies)
Sequence
Varies — characterized by 6 conserved cysteine residues forming 3 disulfide bonds
Dosage Protocols
Dose Range
100mcg – 500mcg
Frequency
Once daily
Route
subcutaneous
Cycle Length
2-4 weeks
No established human dosing protocol. Dosing extrapolated from research models. Primarily of academic interest rather than practical supplementation.
Source: Preclinical research literature
🧮 Personalized Dosage Calculator
💰 Estimated Pricing
Typical Supply
1mg vial
Last Updated
2026-02
Antimicrobial peptide family. Research-grade only. Multiple variants (alpha, beta defensins). Academic supplier pricing.
⚠️ Prices are estimates based on publicly available data and may vary significantly by vendor, location, and prescription status. This is not medical or financial advice.
Side Effects
| Effect | Severity |
|---|---|
| Local irritation | mild |
| Inflammatory response | moderate |
| Allergic reaction | moderate |
Pros & Cons
Broad-spectrum antimicrobial activity against bacteria, fungi, and enveloped viruses
Natural human immune peptides with established biological roles
Bridge innate and adaptive immunity by recruiting immune cells
Potential for combating antibiotic-resistant infections and biofilms
No established human therapeutic dosing protocols
Complex disulfide bond structure makes synthesis expensive
May be inactivated by salt concentrations present in body fluids
Overexpression linked to inflammatory conditions like psoriasis and IBD
Research Studies
🩸 Blood Work
No specific bloodwork requirements reported for this peptide. General health panels are always recommended before starting any peptide protocol.
Legal Status
Naturally occurring peptides. Synthetic analogs available as research chemicals. Not FDA-approved as therapeutics. No specific regulatory restrictions in most jurisdictions.
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