Why should I wear sunscreen?

Arthur W. Perry, MD
Plastic Surgery
Small doses of sunshine are great for you -- vitamin D levels increase and that light is a natural mood elevator. But more than 20 minutes of ultraviolet (UV) light is actually harmful. UV light causes skin cancer and prematurely ages the skin. Beyond 20 minutes and your immune system actually gets suppressed. So, everyone needs to apply sunscreen if you're exposed to the sun for more than 20 minutes. Melanin is your body's own sunscreen. The darker your skin color, the more you have. The lighter your skin, the more important sunscreen is. Even if you have very dark skin, your own sun protection factor (SPF) level is only 16 and so you still need sunscreen.

Short of staying out of the sun altogether, sunscreen is a person's next best defense against premature skin aging and skin cancer. People should use sunscreen any day that they'll be in the sun for a total of 20 minutes or more.

Sunscreens contain a variety of ingredients that either reflect, absorb, or scatter ultraviolet (UV) radiation. Sun protection factor (SPF) refers to a sunscreen's ability to protect a person's skin from some UV rays and gives a measure of how long it would take a person's skin to burn while wearing the product. Generally, the higher the SPF, the more a sunscreen protects from the sun, but this is based on individual sun sensitivity. For example, for an extremely fair skinned person who typically burns after only 5 minutes in the midday sun, a sunscreen with an SPF of 30 will increase the time it takes his or her skin to burn to 150 minutes (5 multiplied by 30).

However, this does not mean people should use sunscreen to increase the amount of time they spend in the sun. Even if a person's skin doesn't burn while in the sun, skin that is exposed to excessive amounts of sunlight is still experiencing sun damage.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.