Polyquaternium-51

What is Polyquaternium-51?

Polyquaternium-51 is a synthetic cationic copolymer made from acrylic acid derivatives and quaternary ammonium compounds, designed for personal care formulations. It belongs to the polyquaternium family of conditioning agents, commonly found in hair conditioners, shampoos, body lotions, and facial moisturizers. In products, it works by attaching to the negatively charged surfaces of skin and hair keratin through electrostatic interactions. This creates a lightweight, flexible film that smooths cuticles, reduces friction, controls static electricity, and enhances manageability. Its humectant properties help bind water molecules, supporting surface hydration without greasiness. The polymer's structure allows it to deposit evenly during application, improving product performance in both rinse-off and leave-on items.

Comedogenic Rating 0/5 Low risk of clogging pores
EWG Safety Rating 1 View on EWG →
PubChem View on PubChem →

Roles in Formulation

This ingredient serves the following purposes in cosmetic formulations:

Film former
Creates a continuous film on skin or hair to improve wear, water resistance, transfer resistance, shine, or hold in sunscreens, makeup, and styling products.
Humectant
Attracts and holds water in the stratum corneum, boosting hydration and plumpness; commonly used in moisturizers, cleansers, and hair conditioners.
Skin conditioning agent
Maintains skin softness, smoothness, and flexibility.

Benefits

Forms a protective layer to lock in moisture and boost skin suppleness.

Reduces static and tangles on hair while improving overall manageability.

Enhances product adhesion for better wear in styling and protective formulas.

Who It's For

A quick guide for who this ingredient may suit (and who should be cautious).

Who May Benefit Who Should Avoid
Individuals with dry or rough skin seeking added smoothness.
Those with confirmed allergies to quaternary ammonium compounds.
People with frizzy or static-prone hair needing conditioning.
People who have reacted to similar synthetic polymers in the past.
Users of daily moisturizers or styling products for hydration support.
Individuals preferring entirely natural or plant-based ingredients.

Safety Notes

  • Rated low hazard by safety assessments, suitable for typical cosmetic use.
  • Minimal irritation potential based on reviews from cosmetic experts.

Frequently Asked Questions about Polyquaternium-51

What does Polyquaternium-51 do in skincare?

It conditions by forming films that smooth skin, retain moisture, and reduce friction.

Is Polyquaternium-51 safe for sensitive skin?

Safety reviews indicate low irritation risk for most users in cosmetics.

Does it clog pores?

Rated non-comedogenic, unlikely to contribute to pore blockage.