Antimicrobial peptides are among the oldest licensed peptide drugs and the least discussed in the grey-market conversation. Vancomycin, daptomycin and colistin are three licensed scaffolds with three different mechanisms.
1. Three scaffolds
Vancomycin is a glycopeptide; daptomycin, a cyclic lipopeptide; colistin, a polymyxin. All are non-ribosomal peptide products of environmental bacteria, held as reserve agents in UK practice because resistance to them is a clinical concern.
2. Vancomycin
Vancomycin binds the D-alanyl-D-alanine terminus of the peptidoglycan precursor, blocking the steps that build the bacterial cell wall. Its activity is concentrated against Gram-positive organisms, including meticillin-resistant Staphylococcus aureus. It is a long-standing licensed POM in the UK.
3. Daptomycin
Daptomycin is the only lipopeptide antibiotic licensed for clinical use. It binds the bacterial membrane in a calcium-dependent manner, oligomerises, and forms ion-conducting channels that depolarise the membrane and halt protein, DNA and RNA synthesis. That action is specific to Gram-positive bacteria; the Gram-negative outer membrane blocks it.
4. Colistin
Colistin is a polymyxin. Its cationic peptide ring binds lipid A of the lipopolysaccharide in the Gram-negative outer membrane, displacing the stabilising cation bridges and disrupting the membrane. It is held back for multi-drug-resistant Gram-negative infections and its use marks last-line prescribing.
5. Licensing and the research-use-only line
All three are licensed UK POMs, governed by the Medicines Act 1968 and the Human Medicines Regulations 2012 and by antimicrobial stewardship: prescribing is restricted, monitored and tied to national surveillance. Nothing here is consumption or dosing advice, and a licensed class extends no assurance to an unlicensed research peptide. Antimicrobial peptides remain under investigation, but research findings are not treatment guidance, and Peptide Data does not claim that any peptide treats, cures or prevents any condition.
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This article is AI-researched and editorially reviewed. It is provided for research and educational purposes only and is not medical advice. Research peptides are not licensed for human consumption in the UK.