Carrageenan is a natural thickening agent which is derived from seaweed and is commonly used as a thickening agent in skin care products. It is a naturally derived thickening agent that imparts a soft, silky feel to skin and hair care products. The feel can turn a little slimy if you add too much so start with around 0.4% and see how that feels. A great thickener for serums as the extract its self is highly moisturising. Usage 2%