The hypodermis is the bottom layer, the fatty layer, of the skin. You need a healthy hypodermis to cushion the internal parts of the body, such as bones and organs. If you fall, a healthy hypodermis can distribute the force of the fall, lessening the impact to the internal structures.

The nerves and blood vessels in the dermis come through the hypodermis to the interior of the body to transmit nutrients and information throughout the body.

The hypodermis also contains a large layer of fat that is responsible for regulating body temperature. This fat layer distributes heat throughout the dermis, which helps maintain a stable body temperature.