The hypodermis is the innermost layer of the skin, and it is made up of fat cells, connective tissue, and blood vessels. HIFU can affect the hypodermis in a number of ways:

• It can heat and destroy fat cells. This can lead to a reduction in fat volume in the treated area.
• It can stimulate collagen production. Collagen is a protein that helps to keep the skin firm and elastic. By stimulating collagen production, HIFU can help to tighten and lift the skin.
• It can improve blood circulation. This can bring more oxygen and nutrients to the skin, which can improve its overall health and appearance.

In addition to these effects on the hypodermis, HIFU can also affect the other layers of the skin, including the dermis and epidermis. However, its effects on the hypodermis are particularly important for its ability to tighten and lift the skin.

Here are some specific examples of how HIFU can affect the hypodermis:

• HIFU can be used to reduce the appearance of cellulite by heating and destroying fat cells in the hypodermis.
• HIFU can be used to tighten and lift the skin on the face and neck by stimulating collagen production in the hypodermis.
• HIFU can be used to improve the appearance of scars by breaking up scar tissue and stimulating collagen production in the hypodermis.