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.
Propylene Glycol is a useful componet with many positive effects. It’s a very good moisturizer. It helps to deliver ingredients into deeper layers of the skin. It creates a protective layer on the skin preventing water loss. The component is researched very well and doesn’t have notable side effects. It’s used even for making food.
Cetearyl Alcohol is used mostly for formulation purposes. It’s a very good emulsifier and emulsion stabilizer. It helps the ingredients mix better and it makes the product spread on your skin evenly. It also makes the product thicker. It doesn’t belong to harmful alcohols and it will not dry your skin.
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%.