Smiling parents holding young children at beach

How to choose the right sunscreen

June 20, 2019 | UCI Health
woman having sunscreen applied to face

Most skin cancers and some 90% of premature skin aging are related to exposure to ultraviolet (UV) radiation from the sun or from indoor tanning.

Science has proven that sunscreen, used correctly, works to prevent skin cancer. But which one is the best?

“The best sunscreen is whatever people will use,” says Natasha Mesinkovska, MD, PhD, UCI Health dermatologist and assistant professor of dermatology at UCI School of Medicine.

“The important thing is to protect your skin.”

Mineral-based sunscreens

If she could choose the sunscreens her patients use, Mesinkovska prefers those with zinc oxide or titanium dioxide. These mineral-based products tend to stay on the skin better and they are more water resistant than chemical-based sunscreens.

These are the white-nose protection sunscreens you often see lifeguards wearing at the beach or pool. These two minerals have been used in sunscreens for more than 30 years. They provide a physical barrier by reflecting UV rays.

Some people reject them as for not being cosmetically attractive — although some brands now offer clear zinc oxide formulas. And because they are thicker, the mineral-based products are a little more difficult to spread on the skin.

At a minimum, be sure to use mineral-based products on babies and children, Mesinkovska says.

Chemical-based sunscreens

Sunscreens with a chemical base use one or more of the following:

  • oxybenzone
  • avobenzone
  • octisalate
  • octocrylene
  • homosalate
  • octinoxate

These chemical-based sunscreens work by absorbing the UV rays.

Once rubbed into the skin, they typically aren’t visible and come in a variety of easy-to-use forms, such as gels, sprays and lotions.

Safety concerns

There is some concern about whether products containing oxybenzone and retinyl palmitate are safe, with some experts suggesting that oxybenzone produces estrogen-like effects and that retinyl palmitate causes cancer.

“According to the FDA right now, they’re safe,” Mesinkovska says.

Another controversy erupted early last month after a study published in the Journal of the American Medical Association reported that the chemicals in sunscreens are absorbed by the body.

Mesinkovska agrees with the FDA’s position, which is that it doesn’t mean these sunscreens are unsafe and that more study is required.

Effects on coral reefs

A third controversy arose when research suggested that chemicals in sunscreen were linked to the bleaching of coral reefs. Hawaii and the Florida Keys have banned their use as a result.

“We have to be careful in using these chemical sunscreens,” she says.

“If more studies confirm the damage to reefs, then the bans may be extended.”

What to look for in a sunscreen

Whether you choose mineral or chemical or spray or lotion, here’s what to look for in selecting a sunscreen:

  • Choose SPF (sun protection factor) of 30 or higher; in California an SPF 45 is even better
  • Use full-spectrum sunscreen that protects against both UVA and UVB rays
  • Choose sunscreens for sensitive skin if a sunscreen irritates your skin
  • Select a mineral-based product for babies and children

Applying sunscreen

Mesinkovska recommends the following strategy when putting on sunscreen:

  • Apply the equivalent of a shot glass — about 1 ounce — of lotion.
  • If you use a spray, apply it until you see it glisten on the skin.
  • Reapply sunscreen every two hours whether in the sun or shade.
  • Slather it on more often if you sweat a lot.  

Products labeled “water resistant” provide protection for 40 minutes when submerged. Those labeled “very water resistant” protect for about 80 minutes.

However, no sunscreen is completely waterproof, so reapply after getting out of the water.

If you’re outdoors frequently

If you don’t have to be outside, Mesinkovska’s advice is to stay indoors, especially between the peak UV hours of 10 a.m. to 4 p.m.

Short of that, she recommends covering up with:

  • Shirts with high necklines and long sleeves
  • Leggings or pants
  • Rash guards
  • Hats with big visors
  • Sunglasses

“Clothing with UV protection is better, but most things will do,” she says. “Some cover is better than no cover.”

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