The "silicon" here is not the silicon element (Silicon) in the chemical element!
The silicon in cosmetics refers to various polysiloxane polymer compounds (Silicone). Most makeup products contain "silicon", and many essences and oil-free creams in skin care products also contain "silicon", especially well-known department store brands.
There are two considerations for adding silicon to skin care products. First, skin care products containing silicon feel smoother and more ductile when applied, which can bring the "fake slippery" texture that some people like. On the other hand, and more importantly, silicon is a very common matrix with strong stability. It can protect the activity of some active ingredients, such as vitamin C that is easily oxidized and denatured, so that the product can work more lastingly.
Because European and American brands usually pay much attention to skin feel, "silicon" will not be absorbed by the skin, nor will it bring any substantial skin care effects other than moisturizing, but it can provide immediate effects such as smoothness, filling pores and wrinkles, and refreshing and non-greasy face feeling.
At the same time, because "silicon" provides a smooth feeling, this ingredient is often added to many shampoos.
Cosmetic silicone oil products are as follows: https://www.personalcaresilicone.com/productcategory-cosmetic-silicone-elastomer-.html