Mills-Peninsula Health Blog

Be Well, Be Well Informed

Sunscreen 101: What to Know

Posted on Jul 28, 2015 in Prevention and Wellness

Sunscreen bottles boast an overwhelming list of features and ingredients. But which ones truly matter when it comes to effective sun protection? In this blog post,  Lisa Hladik, M.D., a Mills-Peninsula internal medicine physician explains.

“Expensive brand-name products are not necessarily better,” Dr. Hladik says. “There are plenty of inexpensive drug store brands that provide the same protection without the high price tag.” Here’s a quick guide to help you pick the right product.

SPF (Sun Protection Factor)

The SPF number on the sunscreen bottle indicates how long you can stay in the sun without risking sunburn. This is calculated by comparing the amount of time it takes for sunscreen-protected skin to burn, compared to the time it takes unprotected skin to burn. For example, if it takes 10 minutes for unprotected skin to burn, wearing an SPF 15 sunscreen will extend your time without sunburn risk to 150 minutes.

Confused by the SPF numbers? Pick a product with at least SPF 30. Very high SPFs are not necessarily better. For example, SPF 30 offers 97.5 percent coverage, whereas SPF 60 only offers a little more with 99 percent protection.

Active Ingredients

Rather than trust the claims on the packaging, look at the list of active ingredients in the product for one or more of the following ingredients that provide the best protection against harmful UVA and UVB rays:

  • Zinc oxide
  • Titanium dioxide
  • Parsol 1789 (Avobenzone) • Mexoryl

 Waterproof Products

The U.S. Food and Drug Administration only allows sunscreen manufacturers to use the terms “water-resistant” (provides sun protection in water up to 40 minutes) and “very water-resistant” (provides up to 80 minutes protection in water) on their products. “Remember, though, whatever the packaging says, you must reapply sunscreen every two to three hours for it to be effective,” Dr. Hladik says.

Broad-spectrum Products

These products offer coverage against both damaging UVA and UVB light. Most products today offer broad-spectrum coverage, although the SPF on the packaging only refers to protection from UVB rays. There is currently no measurement for UVA protection on American sunscreens.

Sensitive Skin

Look for products that list only zinc oxide and/or titanium dioxide in the active ingredients, as they will not irritate sensitive skin. These ingredients form a barrier to physically block the sun’s rays from penetrating the skin. Chemical-based products absorb the sun’s rays and dissipate them as heat. These are also effective and safe if you have no skin sensitivities.

Learn more about the best ways to protect yourself from the sun’s harmful ultraviolet rays on our blog.

Hladik Lisa Hladik, M.D., is a Mills-Peninsula internal medicine physician.