Why are most commercial sunscreens better at blocking UVB rays than they are at blocking UVA rays?

Answer by  dr84bhl (2789)

A commercial sunscreen does block both uvb/uva as they both damage the skin. The uvb rays are the ones that burn your skin and do the most damage. The uva rays age the skin prematurely so are blocked but not so high as the uvb. The higher the number the more protection on the uvb.

Answer by  sarsie1 (92)

UVB blockers have been around longer, and had more study done on them. Initially, we believed that sunburn was the only indicator of the risk of skin cancer. We have since learned that the rays that cause burn (UVB) are not the only ones that cause cancer, and thus we have begun to work on blocking UVA rays as well.

Answer by  Jojo87 (11)

Most commercial sunscreens are better at blocking UVB rays than UVA because even though UVB rays are strong and fast, they only penetrate your top skin layer and give you a tan, while UVA are slower but can penetrate the deeper layers of your skin and cause damage like cancer.

Answer by  G12345 (1808)

Most are better at UVB because UVB are the bandwidth that is responsible for burning and for cancer. UVA is responsible for aging and wrinkles. Thus preventing cancer and burns trumps aging. Best to have a sunscreen that protects against both so that you get the best of both worlds.

Answer by  TheDocta (24)

The reason why commercial sunscreens are better at blocking UVB rays than they are at blocking UVA rays is because UVA Rays are much stronger than UVB rays. UVB rays are the rays that are responsible for causing sunburns where UVA rays are the scapegoat for causing skin aging and wrinkles.

Answer by  Liz59 (10966)

Well that is because they lack the necessary ingredients needed for UVA rays. They don't have uva blocking compounds found in special sunscreens.

Answer by  Latin4 (11170)

After watching a TV show on sunscreen, the best are 45 SPF sunblock. That means that it block's 45% of the sun rays from penetrating your body. There are higher ones that cost more money but 45 is the best. The spokeperson said the higher, like 75 SPF does not block out 75%.