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All peptides
AntimicrobialInvestigational

Gramicidin S

Topical
Written by Peptide Association Editorial TeamMedically reviewed by Ian Justl Ellis, MD, CPTLast reviewed Editorial policy

Overview

Gramicidin S is a cyclic decapeptide antibiotic isolated from Bacillus brevis, consisting of two identical pentapeptide sequences joined in a ring structure. The peptide exerts antimicrobial activity by disrupting bacterial cell membrane integrity through interaction with phospholipid bilayers, leading to leakage of cellular contents.

Mechanism of Action

Its amphipathic beta-sheet conformation enables selective insertion into bacterial membranes. The compound demonstrates broad-spectrum activity against both Gram-positive and Gram-negative organisms.

Research Summary & Key Findings

Gramicidin S has been used primarily as a topical antimicrobial agent in certain countries, particularly in the former Soviet Union, but is not FDA approved for systemic use due to hemolytic toxicity and nephrotoxicity. In vitro studies have confirmed potent activity against multidrug-resistant bacteria, including Pseudomonas aeruginosa and Staphylococcus aureus. Current research focuses on structural analogs with improved therapeutic indices for potential topical or surface decontamination applications.

Clinical Status

Investigational

Gramicidin S is in the investigational stage. While preclinical and early-phase data exist, it has not received regulatory approval for clinical use in the United States.

Administration Routes

Topical

References

Primary literature

Study-level citations for this compound are being verified against the primary sources before publication. The database queries above return the current indexed literature in the meantime.

Related Peptides in Antimicrobial

No lawful pathway today

Gramicidin S is not FDA-approved and does not currently have a lawful prescription or compounding pathway in the United States, so there is nothing for us to sell you here and no consultation to book. That can change: eight peptides moved back to a lawful pathway in February 2026.

Tell me if the status changes

One email, only if this compound's regulatory standing actually moves. Not a newsletter, not a sales sequence.

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Disclaimer: This information is provided for educational and research purposes only. It is not intended as medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider before starting any peptide therapy. The Peptide Association does not endorse or recommend any specific treatment protocol. See our editorial policy for how this content is produced and reviewed.