The cause of double chin can be but does not have to be overweight or obesity. Excess fat is very likely to be the most common factor of the double chin. When your weight is increased, the tendency is to see fat deposited all over the body including the face and under the chin.

Ageing skin is one of the other most common factors to double chin. As you age, your skin produces less collagens, which causes your skin to lose its elasticity and become sagging. When the skin under your chin starts to sag, it creates the same effect as if your under chin has extra fat in the same space. In this case, it is fair to say that the factors that cause skin ageing can also be the factors of the formation of double chin.

In addition, poor posture can also cause the formation of a double chin. People always tend to crane the next over to see or focus on what they are doing, which not only potentially causes neck pain, but also harmful to the platysma muscle. The platysma muscle connects the neck to the chin, when it is weakened, the elasticity around the chin and the sagging effect goes with it.

Double chin can also be caused by your facial structure. This is because the skin is stretched over a smaller area, as it is not as tightly drawn over the face, it takes a minimum upturn in fat or a decrease in skin elasticity to develop a double chin.

Additionally, genetic reason is also a factor of having double chin.