Water is a great solvent. It’s neutral and doesn’t provide any strong positive or negative effects. It just helps components to mix better and to transport active components.
Cocamidopropyl Betaine is a pH 4.5-5.5 liquid that is used to improve the overall efficiency of the formulation. It’s usually combined with different surfactants and is used because of its cleansing efficiency. It helps to remove sebum and dirt from the skin and hair. It also works as a foaming agent helping to make a pleasant foam.
Cetrimonium Chloride is used mostly for formulation purposes and doesn't provide any strong skincare effects. Used mostly to help mix different components together. It also helps to increase the shelf life of the product. CIR safety report tells that this ingredient was found to be “…safe for use in rinse‐off products and …safe for use at concentrations of up to 0.25% in leave‐on products.”
In the European Union (EU), cetrimonium chloride and steartrimonium chloride were reported to be used as a preservative at up to 0.1%. They are also used in rinse-off hair care products at up to 2.5%, leave-on hair products at up to 1.0%, and in leave-on facial cream products at up to 0.5%.