There is no clear margin between this and the dermis. It is formed primarily by fat tissue. This meshwork supports tiny lymph and blood vessels that allow the skin to breathe and be nourished. There are nerves, muscle cells, sweat and sebaceous glands, and hair follicles.

This subcutaneous fat varies in thickness in different regions of the body, and represents an energy source for the body and helps to insulate the body against changes in the outside temperature.