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.
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%.
Fragrance is a mix of chemical ingredients (usually 20-30 chemicals but up to 200 sometimes) that help the product to smell better. It can hide many bad things. Synthetic fragrances may contain many different chemicals, but manufacturers don’t want to reveal each of them for some reason and hide them behind the word "Fragrance".