The hypodermis is the deepest layer of skin, lying beneath the dermis and epidermis. It is also referred to as subcutaneous tissue. It is designed to conserve energy and is made up of cells that store fat for the body's use.
The hypodermis connects outer skin to the tissue underneath it, while regulating body temperature. The hypodermis contains fat cells, connective tissue and fibroblasts. Fibroblasts are responsible for collagen production, which keeps the skin youthful. The hypodermis also houses larger blood vessels and nerves than the other layers of skin. The size of the hypodermis varies from person to person, and often accumulates in different areas on men and women.