Skin is comprised of three major layers: the epidermis, dermis, and sub cutis. The layer hugging our insides is known as the sub cutis—fat that insulates our body and absorbs shock to prevent injury. Directly above sits the dermis, which consists primarily of the protein collagen. Collagen provides our skin with structure to give it strength and flexibility. Finally, the epidermis is the outermost wrapping, and the one skincare products are most concerned with.