Poly-L-Lysine
A polymer of the amino acid lysine. It forms a film on skin, holds moisture and supports smoothness. Well tolerated.
Evidence by route
Topical application
A hydrating film-forming polymer. Safe.
- CIR Cosmetic Ingredient Review safety assessment
How to read tiers A–F
- BLimited evidence. One RCT or several controlled studies with limitations
Tolerability and safety
- Irritation potential
- Low
- Allergen risk
- Low
- Pregnancy
- Safe
- Suitable for
- Normal, Dry, Combination, Oily, Sensitive
About this ingredient
Poly-L-lysine (INCI: Poly-L-Lysine, 30000-70000 MW) is a polymer made of units of the amino acid lysine. In formulas it acts as a film-former and humectant: it forms a thin film on the skin that holds water and leaves a smooth feel. Its efficacy is that of a functional texture and comfort ingredient, not a targeted active. It gives an even finish and supports the feel of soft, hydrated skin, without a deep treatment mechanism. In some formulas its profile is also used to support preservation. Topically its systemic absorption is minimal, so it can be used during pregnancy and breastfeeding. Tolerance is good: low irritation and allergy potential, suitable for sensitive skin. It is a quiet ingredient, comfortable in serums and light emulsions.
Frequently asked questions
Is Poly-L-Lysine safe during pregnancy?
Poly-L-Lysine is considered safe during pregnancy at typical cosmetic concentrations. Systemic absorption through the skin is minimal.
What skin types is Poly-L-Lysine for?
Poly-L-Lysine suits: normal, dry, combination, oily, sensitive.
What is Poly-L-Lysine and what does it do in cosmetics?
A polymer of the amino acid lysine.
What's the INCI name for Poly-L-Lysine?
The INCI name is Poly-L-Lysine (30000-70000 MW). It may also appear as: Polylysine.
See Poly-L-Lysine in a product composition right on the store page
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Polybutene, Polyglucuronic Acid, Polyglutamic Acid, Polyglycerin-3, Triticum Vulgare Germ Extract, Caprylic/Capric Triglyceride, Glyceryl Oleate, Isomalt
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