Chondrus crispus, also known as Irish moss or carrageen moss, is a species of red algae. The principal component of Chondrus crispus is a viscous substance made of the polysaccharide carrageenan, which constitutes 55% of its dry weight. Carrageenan is used as a thickener and emulsion stabilizer in foods such as ice cream and processed foods.

In cosmetics and personal care products, carrageenan functions as a thickening agent, binder, and conditioning agent. It imparts a smooth, creamy texture to products, and is often used in the formulation of gels. Carrageenan can also stabilize a variety of formulations such as emulsions, foams, and suspensions. Carrageenan has excellent water binding properties. This means it attracts and holds water onto the skin/hair, which provides a conditioning effect. Carrageenan can be found in products such as toothpaste, shampoo, conditioner, shaving cream, foundation, sunscreen, and other skin care products.