A double chin is broadly divided into the fat type, where fat accumulates, and the sagging type, where skin and tissue have loosened. Identifying the cause is the starting point for choosing a method. If, when you gently pinch the area under the chin, you feel a thick layer of fat, it is closer to the fat type. If the skin folds loosely rather than feeling thick, the sagging type is more prominent.
The fat type is closely related to body weight, genetics, and accumulation of fat under the chin (submental fat). The sagging type occurs as collagen decreases with age and the jawline tissue descends. Collagen is known to decrease by about 1% per year starting from one's 20s, so the proportion of sagging factors tends to increase with age.
Since the two types often appear together as a mixed type, an evaluation that comprehensively considers fat volume, skin elasticity, and jawline shape is accurate. In clinical practice, most cases involve a combination of the fat type and the sagging type.



