Photoaging representative UV rays A(UV-A) and
B(UV-B) coming through the atmosphere penetrate to the skin.
UV-B energy is concentrated in the epidermis represents
the effect of burning the skin.
As a result of UV-A coming through to the dermis,
generating lots of active oxygen and destroying the collagen,
elastin & hyaluronic acid causes the skin aging.
In other words, UV-A is an actual main cause of skin aging
※ other factors as UV rays are the representative external factor of skin aging,
many other things like as infrared light, smoking, drug consumption,
menopause & etc. are associated.