What factor is most responsible for the aging of the skin, accounting for 80-85%?

Sun exposure is the primary factor responsible for the aging of the skin, accounting for approximately 80-85% of skin aging. This phenomenon is often referred to as photoaging and is caused by the ultraviolet (UV) rays emitted from the sun. These rays lead to various skin changes, including the breakdown of collagen and elastin fibers, leading to wrinkles, sagging, and loss of skin elasticity. Additionally, UV radiation can cause pigmentation changes, such as sunspots and uneven skin tone.

In contrast, while diet, genetics, and smoking can contribute to skin aging, they do not have the same significant impact as sun exposure. A poor diet can affect skin health and appearance, but its effect is less direct and often less severe than that of sun exposure. Genetics plays a role in determining one's predisposition to skin aging, yet it is not an external factor like sun exposure. Smoking can cause premature aging due to reduced blood flow and oxygen to the skin, but still, it accounts for a smaller percentage of skin aging compared to the effects of sun exposure.