How does the Sun Cause Skin Aging?
It is difficult for us to avoid the sun. Sunlight has infrared radiations and ultraviolet radiations. These radiations cause changes in the skin. Ultraviolet (UV) radiation is invisble, doesn’t feel warm and can cause unpleasant or dangerous effects on the skin: A little UV light is helpful to make vitamin D, but overdoing it causes acute radiation injury to skin (sunburn), damages the DNA of our skin cells (leading in some cases to skin cancer), increases the breakdown of collagen, the main supporting protein of our skin leading to wrinkles and photo-aging, causes skin pigmentation and freckling (compare the inside and outside of your forearm now for a demonstration), and can cause the development of permanent blood vessels on the cheeks.