SPF – Sun Protection Factor
Who should wear SPF?
Everyone. Sunscreen protects you from harmful UV (ultraviolet) rays, which can cause skin cancer and premature aging of the skin.
How much sunscreen do I need and how often?
Most adults need about 1 ounce — or enough to fill a shot glass — to fully cover their body and about 1/2 a teaspoon to cover the face. Sunscreen should be applied 15 minutes before going outdoors on dry skin. Once outside, it should be reapplied every two hours, as well as after sweating or swimming.
Why do I need a broad-spectrum SPF?
The two basic types of ultraviolet rays that reach the earth’s surface are UVB and UVA rays. The UVB can produce sunburn and plays the biggest role in causing skin cancers, including melanoma. The UVA rays, which penetrate more deeply into the skin, can also contribute to skin cancer, and, in addition, are responsible for premature aging of the skin. You want a sunscreen that says “broad-spectrum” to protect your skin from both UVB and UVA damage.
Is a high-number SPF better than a low-number one?
We recommend using a sunscreen with an SPF of 30 or above, which blocks 97 percent of the sun’s UVB rays. While higher-number SPFs block slightly more of the sun’s UVB rays, there are no sunscreens that can block 100 percent of the sun’s UVB rays. It is very important to remember that SPFs with higher numbers do not last longer than low-number SPFs. Any sunscreen, regardless of number, should be reapplied about every two hours when spending time outside, even on cloudier days.
Sun Protection Factor (SPF) measures a sunscreen’s ability to shield skin from harmful UV rays. A higher SPF indicates longer protection, reducing sunburn risk. However, SPF only quantifies UVB protection; UVA protection isn’t fully indicated. Regular application and protective measures remain vital for comprehensive sun defense.