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Evidence: MediumPeptide Research Only Immune & Anti-Inflammatory

Cecropin

also known as: Cecropin A, Cecropin B, Cecropin P1

The insect immune system's first-line antibiotic — among the earliest AMPs discovered, proving innate immunity uses peptide weapons across the animal kingdom.

A family of 35-39-amino-acid cationic alpha-helical antimicrobial peptides from the cecropia moth that kill Gram-negative bacteria by membrane disruption without significant mammalian cell toxicity.

Mechanism of action

Two-helix structure: N-terminal helix binds bacterial membrane surface, C-terminal helix inserts into the hydrophobic core. Acts via the 'carpet model' — lining membranes until threshold causes micelle-like dissolution. Highly selective for bacterial membranes.

Primary uses

  • Research: model AMP for innate immunity
  • Template for hybrid AMP design
  • Agricultural biotechnology: transgenic disease resistance

Typical dosing

N/A N/A N/A (research only)

Research MICs 1-10 mcM against Gram-negative pathogens.

Regulatory status

Not approved. No cecropin derivatives have reached clinical trials as of 2026.

Status as of this entry's last review, April 21, 2026. Approvals, compounding rules and sport rules change; the regulatory tracker is checked more often.

What the studies show

Cecropins are antimicrobial peptides first found in insects. Their research is in insects, farm animals and laboratory expression systems; no study has given a cecropin to people.

Animal · 2012

Broiler chickens

A cecropin A-D hybrid peptide in feed reduced intestinal bacterial counts and increased villus height in a dose-dependent way in broilers, which the authors propose as an alternative to antibiotic growth promoters.

PMID 22251659

Animal · 2012

Weaned piglets

Cecropin AD improved growth performance and immune markers and reduced intestinal pathogens in newly weaned piglets.

PMID 22490448

Animal · 2005

Calves

A cecropin B gene delivered to the nasal mucosa of calves prevented colonization by Mannheimia haemolytica serotype 1 in most animals at the higher DNA dose, and cecropin B killed the bacterium in vitro.

PMID 16334951

Animal · 2024

Malaria mosquitoes

A cecropin from Anopheles gambiae mosquitoes was broadly antibacterial and active against the stage of the malaria parasite transmitted to humans, which the authors see as a possible transmission-blocking agent.

PMID 39441862

In Vitro · 2021

Making it in bacteria

Cecropin B was produced in bacteria fused to a SUMO tag, with codon optimisation, as a way to manufacture antimicrobial peptides.

PMID 34018140

References

  1. [pubmed] Steiner H, et al. "Sequence and specificity of two antibacterial proteins involved in insect immunity." Nature, 1981;292(5820):246-8. PMID: 7019715.
  2. [review] Boman HG. "Antibacterial peptides: basic facts and emerging concepts." J Intern Med, 2003;254(3):197-215. PMID: 12930229.
  3. [pubmed] Wen LF, et al. "Dose-response effects of an antimicrobial peptide, a cecropin hybrid, on growth performance, nutrient utilisation, bacterial counts in the digesta and intestinal morphology in broilers." Br J Nutr, 2012;108(10):1756-63. PMID: 22251659.
  4. [pubmed] Wu S, et al. "Effects of the antimicrobial peptide cecropin AD on performance and intestinal health in weaned piglets challenged with Escherichia coli." Peptides, 2012;35(2):225-30. PMID: 22490448.
  5. [pubmed] Boudreaux CM, et al. "Effects of cecropin B transgene expression on Mannheimia haemolytica serotype 1 colonization of the nasal mucosa of calves." Am J Vet Res, 2005;66(11):1922-30. PMID: 16334951.
  6. [pubmed] Barreto C, et al. "A novel broad-spectrum antibacterial and anti-malarial Anopheles gambiae Cecropin promotes microbial clearance during pupation." PLoS Pathog, 2024;20(10):e1012652. PMID: 39441862.
  7. [pubmed] Park AR, et al. "Expression of Antimicrobial Peptide (AMP), Cecropin B, in a Fused Form to SUMO Tag With or Without Three-Glycine Linker in Escherichia coli and Evaluation of Bacteriolytic Activity of the Purified AMP." Probiotics Antimicrob Proteins, 2021;13(6):1780-1789. PMID: 34018140.

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Guides & tools

Disclaimer

This entry is for educational purposes only and does not constitute medical advice. Dosing information reflects published regulatory or research data and is not a recommendation. Many compounds described here are not approved for human use in the United States. Consult a licensed medical professional before considering any peptide therapy.