Ingredient Guide
Polylysine
Also known as: Epsilon-Polylysine, ε-Polylysine, Poly-L-Lysine
All skin types
What It Is
A naturally derived polypeptide produced by fermentation of Streptomyces albulus bacteria. Used in cosmetics as a natural preservative with antimicrobial properties relevant to both preservation and acne-targeting applications.
What It Does
Polylysine disrupts bacterial cell membranes and has documented efficacy against gram-positive and gram-negative bacteria — providing natural preservation while contributing antimicrobial function in acne-targeting formulas.
Best For
Natural preservationAntimicrobial support
Benefits
- Natural antimicrobial preservation from fermentation
- Active against gram-positive bacteria including acne-associated strains
- Non-synthetic alternative for preservation
When to Be Careful
- Primarily a functional preservative ingredient
ItGirlies Ingredient Intelligence
Best Routine Slot
As part of the formula it is in.
Good Match For
Functional ingredient — natural preservation with bonus antimicrobial relevance in acne formulas.
Proceed Carefully If…
No known concerns.
Signs You May Be Overdoing It
N/A
Commonly Found In
Spot TreatmentsAcne Serums
FAQs About Polylysine
What is polylysine in skincare?
A naturally derived polypeptide preservative with antimicrobial activity against bacteria. Used in acne-targeting formulas where its preservation and antimicrobial functions overlap.