Antimicrobial

α-Defensin 1 (HNP-1)

Human Neutrophil Peptide 1 · HNP-1 · DEFA1

α-Defensin 1 (HNP-1) is a terrifyingly efficient, endogenous biochemical weapon manufactured directly by human neutrophils. Stored heavily within azurophilic granules, it acts as the immune system's absolute first line of brutal physical defense against invading pathogens. In elite immunology research, it is studied for its ability to literally shred bacterial membranes and violently bridge the gap between innate reaction and adaptive immune memory.

Not FDA-approved - research chemical
Reviewed by CalcMyPeptide Editorial Team
Last updated: August 2026Evidence: Low1 peer-reviewed citation
Typical research dose
Research only
Frequency
Per study protocol
Half-life
Short - minutes to hours in circulation
Common vials
1 mg
Molecular weight
3441.9 g/mol

Use-case scores

0–10 against the evidence we have, not a gym ranking. Hidden domains do not apply here.

  • Immune2.5/10

    Innate AMP biology. Injectable research-chem is not an antibiotic.

Compound card

Class
Human neutrophil peptide (HNP-1; AMP)
Formula
C147H229N45O40S6
Status
Not FDA-approved · research use

How it works

Human Defensin Alpha-1 (HNP-1, Human Neutrophil Peptide-1) is a cationic antimicrobial peptide (AMP) produced by neutrophils and Paneth cells. It kills bacteria, fungi, and enveloped viruses by inserting into microbial membranes and creating pores. Simultaneously, it acts as a chemoattractant for dendritic cells and T cells, bridging innate and adaptive immunity. Research interest spans wound care, antiviral protection, cancer immunomodulation, and potential gut mucosal defense.

Source: PMID: 12379468

Research Use Cases

  • ✓Antimicrobial / Immune Modulation: Emerging

Dosing

PhaseDoseFrequencyNotes
Research UseVariable (µg range)In vitro / topical / IV (animal models)No established human therapeutic dose.

Administration

Route / form
Topical or IV (preclinical research)
Timing
No human protocol established
Empty stomach?
No - Food timing is not critical.

Timeline

Immediate (in vitro)
Rapid membrane disruption of gram-positive and gram-negative bacteria.

Who it is for

Antimicrobial / Immune Modulation

Emerging

Potent AMP with immunomodulatory properties - research-stage only.

Safety & Considerations

Research peptide only. No established human dosing protocol. In vitro and animal studies indicate cytotoxicity at high concentrations - selectivity for pathogens vs host cells is dose-dependent.

Regulatory & Legal Status

FDA Status (US)
Research Only
WADA Status (2026)
Not Listed

Not currently on the WADA 2026 Prohibited List. Policies may change - verify before competition.

Classification

Research Chemical

US Compounding: Not eligible / not available

⚠️ This information is for educational purposes only and may not reflect the most current regulatory updates. Always verify with official FDA, WADA, and jurisdiction-specific sources before use.

Limits of current evidence

  • This site will not treat infection from a defensin page.

Verdict

α-defensin-1 is an endogenous antimicrobial peptide. Vials are not a substitute for indicated antimicrobials. Not LL-37.

Interactions & Contraindications

Research peptide only. No established human dosing protocol. In vitro and animal studies indicate cytotoxicity at high concentrations - selectivity for pathogens vs host cells is dose-dependent.

Frequently Asked Questions

What is defensin alpha-1 used for in research?▼
HNP-1 is studied for antimicrobial applications (antibiotic alternatives), antiviral defense, wound healing, and cancer immunotherapy adjuncts. It is not used clinically in humans as a standalone therapeutic.

References

  1. Ganz T “"Human defensin-1 and -2: biological properties and functional activity".” Science (1985). PMID: 6242282

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