Sun Protection Factor Description
Most commonly seen as SPF followed by a number, it is a rating system assigned to a product that identifies the amount of time it can protect the skin from sunburn or from turning pink or red when exposed to sun. In the United States, SPF ratings are regulated by the Fod & Drug Administration. Because sunburn results from UVB radiation, not UVA radiation, SPF is primarily a measure of UVB protection; however, sunscreens rated for broad spectrum protection can protect from UVA rays, too.
Peer-reviewed, substantiated scientific research is used to assess ingredients in this dictionary. Regulations regarding usage constraints, permitted concentration levels and availability vary by country and region.