Best sunscreen: Understand sunscreen options

The best sunscreen is one that you'll use generously and according to label directions. Here's help understanding sunscreen ingredients, types of sunscreen and more. By Mayo Clinic Staff

Confused about the best sunscreen to use? Wondering whether sunscreen can be harmful? Lawrence Gibson, M.D., a dermatologist at Mayo Clinic, Rochester, Minn., offers his guidance.

What's the best way to sort through information about sunscreens?

Start by remembering the bigger picture when it comes to sun safety and what you can do to protect yourself. For example:

  • Avoid the sun during peak hours. Generally, this is between 10 a.m. and 2 p.m. — regardless of season. These are prime hours for exposure to skin-damaging ultraviolet (UV) radiation from the sun, even on overcast days.
  • Wear protective clothing. This includes pants, shirts with long sleeves and sunglasses. Top it off with a wide-brimmed hat. Also, consider investing in sun-protective clothing or using an umbrella for shade.
  • Use sunscreen. Apply sunscreen generously and reapply regularly.

Is there any truth to the claim that sunscreen use encourages excessive sun exposure and, as a result, increases the risk of skin cancer?

Most experts strongly disagree with this claim. Research also hasn't shown a link between sunscreen use and an increase in the risk of skin cancer. On the other hand, research has shown that use of sunscreen can reduce the risk of melanoma, the most serious type of skin cancer.

What does a broad-spectrum sunscreen do?

There are two types of UV light that can harm your skin — UVA and UVB. A broad-spectrum, or full-spectrum, sunscreen is designed to protect you from both.

UVA rays can prematurely age your skin, causing wrinkling and age spots. UVB rays can burn your skin. Too much exposure to UVA or UVB rays can cause skin cancer. The best sunscreen offers protection from all UV light.

Does the best sunscreen also have the highest SPF?

SPF stands for sun protection factor, which is a measure of how well the sunscreen deflects UVB rays. Manufacturers calculate SPF based on how long it takes to sunburn skin that's been treated with the sunscreen as compared with skin that hasn't been treated with sunscreen.

Theoretically, the best sunscreen has the highest SPF number. It's not that simple, however. When applied correctly, a sunscreen with an SPF of 30 will provide slightly more protection from UVB rays than does a sunscreen with an SPF of 15. But the SPF 30 product isn't twice as protective as the SPF 15 product. Sunscreens with SPFs greater than 50 provide only a small increase in UVB protection.

Also, keep in mind that sunscreen is often not applied thoroughly or thickly enough, and it might be washed off during swimming or sweating. As a result, even the best sunscreen might be less effective than the SPF number on the bottle would lead you to believe.

Rather than looking at a sunscreen's SPF, choose a broad-spectrum sunscreen that will protect you from UVA and UVB rays.

Jun. 04, 2013 See more In-depth