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.
Uvasorb HEB (also known as diethylhexyl butamido triazone; DBT; iscotrizinol) is used in concentrations of up to 10%. It filters UVB rays, and some UVA rays.
It’s an ideal addition to broad spectrum sunscreens, but is not available in the US or Canada. Products that come from Europe or Asia may contain 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.