Sunscreen

Sunscreen, also known as sunblock or sun lotion, is a topical product designed to protect skin from ultraviolet radiation. By reducing penetration of UV rays, it helps prevent sunburn, premature aging, and skin cancer, and it is commonly used during outdoor activities and in daily skincare routines.

Most sunscreens contain chemical (organic) filters that absorb UV light and convert it to heat, or mineral (inorganic) filters such as zinc oxide or titanium dioxide that reflect or scatter UV radiation. Many products label themselves as broad-spectrum, indicating coverage against both UVA and UVB rays.

SPF, or sun protection factor, mainly measures protection against UVB-induced erythema (sunburn). UVA protection is often indicated separately or as a broad-spectrum claim. Some regions use additional ratings such as UVA-PF or PA to denote UVA coverage.

Usage guidelines include applying sunscreen to all exposed skin about 15 to 30 minutes before going outdoors, and reapplying at least every two hours, or more often after swimming, sweating, or towel drying. Water-resistant formulations last longer in water, but still require reapplication.

Formulations include lotions, creams, gels, sticks, and sprays. Application should be even and thorough, and care should be taken to avoid eyes and inhalation when using sprays. People with sensitive skin may prefer mineral sunscreens or fragrance-free products. Children under six months should be kept out of direct sun; protective clothing is advised.

Storage should be in a cool place and used before the expiration date. In some regions, environmental concerns influence product choices, with reef-safe formulations avoiding certain chemicals that have been linked to coral damage.