Broad-spectrum SPFSunscreen · SPF

Broad-spectrum SPF describes a sunscreen that protects against both UVB (which burns) and UVA (which drives ageing and contributes to skin-cancer risk). The SPF number chiefly reflects UVB protection; 'broad-spectrum' signals meaningful UVA cover too.

It matters because the evidence here is unusually strong for skincare: randomised trials link regular sunscreen use to slower skin ageing and to roughly halved melanoma incidence at long-term follow-up.

In practice, daily use on exposed skin, applied generously and reapplied, is what those trials modelled; it is the single highest-evidence step for both skin health and appearance.

Sources

• Hughes MCB, Williams GM, Baker P, Green AC. Sunscreen and prevention of skin aging: a randomized trial. Ann Intern Med 2013;158(11):781-790
• IARC / WHO. Sunbeds and UV radiation, with UV-emitting tanning devices classified Group 1, carcinogenic to humans (El Ghissassi F, et al. Lancet Oncol 2009)