Understanding SPF: Dermatologists Explain Sun Protection Levels
Understanding SPF: Dermatologists Explain Sun Protection Levels
US · Published May 31, 2026
Dermatologists are emphasizing the importance of sunscreen in protecting against harmful ultraviolet (UV) rays, particularly UVB and UVA rays, which can cause sunburns, wrinkles, and skin cancer. SPF, or Sun Protection Factor, measures how well a sunscreen protects against UVB rays. SPF 30 filters about 97% of UVB rays, while SPF 50 filters 98%, and SPF 100 filters 99%. However, no sunscreen can block 100% of UVB rays, and the FDA has banned the term 'sunblock' since
Experts recommend using at least SPF 30 sunscreen, applying it generously, and reapplying every two hours or after swimming or sweating. Broad-spectrum sunscreens, which protect against both UVA and UVB rays, are advised, along with water-resistant options for activities involving water or heavy perspiration. Additional sun protection measures include wearing wide-brimmed hats, sunglasses, and sun-protective clothing, and avoiding peak UV hours between 10 a.m. and 4 p.m.

Why It's Important?

Inadequate sun protection can lead to severe health risks, including sunburns, premature aging, and an increased likelihood of developing skin cancer. People with lighter skin tones are at higher risk, but individuals with darker skin tones are not immune to UV damage. Misunderstanding SPF levels or failing to apply sunscreen correctly can result in insufficient protection. High SPF products may create a false sense of security, leading users to stay in the sun longer without reapplying. Additionally, UVA rays, which are not measured by SPF, can penetrate deeper into the skin, causing long-term damage.

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