Sunscreens are designed to prevent the transfer of solar energy rays to the skin. When there is an over supply of solar energy on the skin it can cause sun burn, uneven pigmentation, photo aging, and increase the risk of skin cancer.
Just ONE severe burn increases the risk of skin cancer. 90% of non-melanoma and 65% of melanoma skin cancer are related to Ultra Violet exposure. Solar energy rays are to blame for 90% of all skin changes related to increased skin aging.
There are two types of sunscreens; those that are Chemical and those that are Physical. Physical sunscreens deflect the sun’s rays. However, small amounts can pass through the barrier. These sunscreens do not affect the skin negatively or cause sensitivity. Physical sunscreens are preferred over Chemical sunscreens. Chemical sunscreens absorb solar energy and transform it into a chemical reaction, which prevents solar energy to be absorbed by the skin.
There are two types of chemical reactions:
1. Solar energy is absorbed by the sunscreen’s molecules which is then chemically transformed into a different chemical and is then quickly transformed back into the original molecule to start the process over again.
2. Much like the first reaction, when the transformation occurs, it turns into a different molecule. However, the transformed molecule becomes a carcinogenic and does not turn back into the original molecule. This process can cause skin sensitivity and as the SPF number increases the sensitivity increases.
Sunscreens with both UVA and UVB protection are called Broad Spectrum. Broad Spectrum is an SPF of 15 or higher. UVB prevention is measured by the SPF number. The wave length of UVA rays is 320 to 400. UVA rays penetrate deeper into the skin and carry more energy. UVB’s wave length is 280 to 320 and penetrates the dermis.