A preservative from the amino acid lysine. It gently limits bacterial growth and helps extend shelf life without harsh preservatives. Well tolerated.
Topical application
BLimited evidence. One RCT or several controlled studies with limitations.
A mild functional preservative. Safe.
Polyepsilon-lysine (INCI: Polyepsilon-Lysine) is a preservative derived from the amino acid lysine, produced by fermentation. In formulas it slows bacterial growth and helps extend shelf life without harsher preservatives. This is a functional ingredient. Its job is to protect the formula, not to care for the skin; without a good preservative system a water-based product spoils and becomes unsafe. It fits formulas that aim for a gentler preservation profile. Topically there is no meaningful systemic exposure, so it can be used during pregnancy and breastfeeding. Tolerance is good: irritation and allergy risk are both low. As an amino-acid-based preservative it tends to be a comfortable option even for sensitive skin, where it causes fewer problems than some classic preservatives.
Irritation potential
LowAllergen risk
LowPregnancy
SafeSuitable for
The Evigrade extension adds an evidence panel to iHerb, Sephora, Druni and 12 more stores. This ingredient and every other one in the product show evidence-tier, allergen risk and pregnancy/lactation flags at a glance.
Polyepsilon-Lysine is considered safe during pregnancy at typical cosmetic concentrations. Systemic absorption through the skin is minimal.
Polyepsilon-Lysine suits: normal, dry, combination, oily, sensitive.
A preservative from the amino acid lysine.
The INCI name is Polyepsilon-Lysine. It may also appear as: Полиэпсилон-лизин, Polylysine.
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