Understanding the active ingredients in sunscreen is a bit like learning a foreign language that uses a different alphabet. Suffice it to say in short that sunscreens are made up of a combination of two types of ingredients: those that reflect ultraviolet (UV) rays and those that absorb UV rays. Although that might sound simple enough, there are also two types of rays: UVA rays and UVB rays. UVB causes sunburn at the outer layers of skin, but UVA causes sun damage that reach deeper layers of skin. Both UVA and UVB radiation can contribute to the development of skin cancer.

Oxybenzone does not offer strong sun protection, but it does help to stabilize other ingredients, which is why it is included in many popular sunscreen formulations.

The unfortunate characteristic that oxybenzone also presents is its risk as a carcinogen. It is known to increase the production of harmful free radicals and to attack DNA cells. Some studies have even suggested that it may cause breast cancer. These characteristics have been ignored by manufacturers on the assumption that it isn’t being absorbed by the skin, but new evidence suggests that if it does enter the skin, it is not easily eliminated. Therefore it may be wise to limit use of sunscreens containing oxybenzone for extended periods and to choose alternate sunscreens completely for children that exclude this ingredient.

Keep in mind that a sunscreen’s Sun Protection Factor (SPF) is a gauge of how well the formula protects the skin from UVB rays. It does not gauge protection from UVA rays.