The U.S. government has officially identified ultraviolet radiation (UVR), both from the sun and from tanning machines, as a known cause of cancer in humans. UVR causes DNA damage that may lead to mutations (abnormalities) in genes associated with the development of skin cancer. Therefore, along with other sun safety strategies, sunscreen that absorbs or blocks UVR serves an important protective function.
Most people use the term "sunscreen" to denote sunblock or sun cream. These can range from creams, lotions, sprays, or other topical products that absorb or reflect some of the sun's ultraviolet (UV) radiation and thus help protect against sunburn. Diligent use of sunscreen can also slow or temporarily prevent the development of wrinkles, moles, and sagging skin.
The more accurate denotation is to differentiate between "sunscreen" and "sunblock" based on their mode of action. Here, we explain the difference.