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.
Hexylene Glycol is mostly used for formulation purposes. It’s a good surfactant, emulsifier, and viscosity-reducing agent. It maintains the density of the formulation of the product preventing it from separating. It also makes the product feel better.
Caprylyl Glycol is a vey popular skincare ingredient. It makes the product spread better and feel better on your skin. It’s a preservative and it improves the effect of other preservatives. It’s also a humectant which helps to retain water. It’s good for keeping your skin in good shape. But manufacturers use it as a supporting component rather than the main one.