Summary: A sunscreen label indicating protection against both UVA and UVB radiation.
"Broad-spectrum" refers to sunscreens that provide measurable protection across both UVA and UVB wavelengths of ultraviolet radiation. While UVB rays are primarily responsible for sunburn, UVA rays penetrate deeper into the skin and contribute to premature aging, pigmentation, and long-term cellular damage.
To be labeled as broad-spectrum in many regulatory systems (e.g., FDA in the U.S. or EU guidelines), a sunscreen must demonstrate a minimum level of UVA protection relative to its UVB protection—typically measured by in vitro or in vivo testing methods such as the UVA/UVB protection ratio or critical wavelength.
Broad-spectrum sunscreens contain ingredients that absorb, reflect, or scatter across a wide range of UV wavelengths. Common broad-spectrum UV filters include zinc oxide and avobenzone.