Side-by-Side Comparison · 2026

Gramicidin A vs Polymyxin B

Gramicidin A vs Polymyxin B — mechanism, half-life, dosing, and research status compared. Which is right for your protocol?

Gramicidin A
Antimicrobial Peptide

Gramicidin A is a 15-residue linear peptide antibiotic from Bacillus brevis, distinct from the cyclic gramicidin S despite sharing the same producer organism. Gramicidin A is the active component in Neosporin and other topical antibiotic combinations....

Calculate Gramicidin A dose →
Polymyxin B
Antimicrobial Peptide

Polymyxin B is a cyclic lipopeptide antibiotic from Bacillus polymyxa that was approved in the 1960s and fell out of favor due to nephrotoxicity, but has experienced a major clinical resurgence as a last-resort treatment for carbapenem-resistant Gram-negative infections (Acinetob...

Calculate Polymyxin B dose →
Key Parameters
Parameter Gramicidin A Polymyxin B
Category Antimicrobial Peptide Antimicrobial Peptide
Research Approved (topical combination) FDA Approved
Half-Life Hours (membrane-bound) 6-8 hours
Typical Dose Component of Neosporin and similar products 15,000-25,000 units/kg/day IV
Frequency As needed Every 12 hours IV
Route Topical (combination products) IV / IM / Topical / Intrathecal
FDA Status Approved (topical combination) Approved (systemic Gram-negative infections)

Calculate doses for both

Use ASCEND's free reconstitution calculator to get exact syringe draw amounts for your vial.

Calculate Gramicidin A Calculate Polymyxin B
Frequently Asked Questions
What is the difference between Gramicidin A and Polymyxin B?
Gramicidin A: Gramicidin A is a 15-residue linear peptide antibiotic from Bacillus brevis, distinct from the cyclic gramicidin S despite sharing the same producer organism. Gramicidin A is the active component in N... Polymyxin B: Polymyxin B is a cyclic lipopeptide antibiotic from Bacillus polymyxa that was approved in the 1960s and fell out of favor due to nephrotoxicity, but has experienced a major clinical resurgence as a l...
Which has a longer half-life, Gramicidin A or Polymyxin B?
Gramicidin A half-life: Hours (membrane-bound). Polymyxin B half-life: 6-8 hours.
Can you stack Gramicidin A and Polymyxin B?
Gramicidin A and Polymyxin B are in the same category and used together in research protocols. Always consult relevant literature and follow appropriate guidelines.

For research use only. Not medical advice. ASCEND does not conduct or endorse any specific research protocol. Always consult relevant scientific literature and regulatory guidelines.