What is the purpose of SPF in sunscreen?

The purpose of SPF, or Sun Protection Factor, in sunscreen is primarily to protect the skin from harmful UV rays. SPF measures the level of protection a sunscreen provides against UVB rays, which are the rays responsible for sunburn and can contribute to the development of skin cancer. An SPF rating indicates how long a person can be exposed to the sun without getting sunburned compared to without sunscreen. For example, if a person would typically burn after 10 minutes in the sun, an SPF 30 sunscreen could theoretically allow them to stay in the sun for 30 times longer (300 minutes) without burning, although factors like sweating, swimming, and reapplication can affect this.

Properly applying sunscreen with an adequate SPF is essential for reducing the risk of skin damage from UV radiation. Other options do not capture the primary function of SPF. While moisturizers can help hydrate the skin and some products may enhance texture or even provide a tan, these are not the main purposes of SPF in sunscreen. The focus remains on the vital role of SPF in protecting skin health and preventing the aggressive effects of UV exposure.