Polylysine

Polylysine is a fermentation-derived, water-soluble cationic peptide made of repeating lysine units. In cosmetics it's used as a broad-spectrum preservative that keeps water-based formulas fresh and stable.
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Ingredient Snapshot

Overview
A fermentation-derived preservative that keeps formulas fresh.
Category
Preservative
Type
Preservative

Ingredient Ratings

Overall Rating

Good

Comedogenic Risk

None

Skin Benefits

Guards products against microbial spoilage, supporting freshness over time. Works efficiently in high-water systems, maintaining product quality between uses.

Uses In Skincare & Cosmetics

Used in water-based serums, gels, and liquid moisturizers to bolster preservation. Also appears in toners and essences for freshness retention.

Comedogenic Rating

This ingredient is not typically evaluated for comedogenicity, and no standardized rating is available.

Safety

Generally low irritation, though its cationic character may cause mild stinging or redness in very sensitive skin at higher levels. Patch testing is prudent for reactive skin. No widely noted cosmetic regulatory restrictions.

Is Polylysine a Good Ingredient?

Good rating because it preserves water-based formulas effectively at low levels and is generally well tolerated, with stable performance across typical cosmetic pH. Its cationic peptide nature provides broad antimicrobial coverage with low irritation potential.

Products with Polylysine

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