Toss your expired sunscreen and opt for physical over chemical products, B.C. doctor says

Summer sunshine is upon us — and it's time to take stock of what you're putting on your skin to stay safe.

When it comes to sunscreen, physical rather than chemical products are the way to go, says Dr. Sachit Shah, director of Beautiful Canadian Laser and Skincare Clinic in Surrey, B.C. — and no matter what, never go to the beach with an expired bottle.

Physical sunscreen, also known as mineral sunscreen, contains active mineral ingredients and blocks UV rays by creating a barrier on top of the skin.

Chemical sunscreens absorb UV rays, convert them into heat, and release them from the body.

But Shah said some of the chemicals used, when exposed to oxygen, can break down into into benzene — a known carcinogen.

According to Health Canada, examples of chemical UV filters include avobenzone, homosalate, octocrylene, octisalate, octinoxate and oxybenzone. 

Instead, Shah recommends a physical sunscreen that contains zinc oxide or titanium dioxide. 

"That is much safer and it works very well," Shah told CBC Radio on Wednesday.

Shah said some people may have an aversion to the physical products because they are known to be more challenging to rub in and often leave skin with a sheen of white on it.

But nowadays, there are many good physical products on the market that can cover your skin without this happening, he said.

In Canada, sunscreens are classified as non-prescription drugs or natural health products, depending on their active ingredients, and are regulated under the Food and Drugs Act. 

On its website, Health Canada notes recent studies in the United States "demonstrate that more information is needed to determine if the ingredients in sunscreens pose a safety risk when absorbed."

At this time, the federal agency says it agrees with its counterparts at the U.S. Food and Drug Administration that sunscreen absorption doesn't equal risk or that the findings don't mean any approved ingredients have now been deemed unsafe.

But all the experts agree that using any type of sun protection product that is expired is a bad idea.

The Canadian Cancer Society says sunscreen should not be used after the expiry date because they may not work as well. 

Sunscreens that have changed colour or consistency, or have been exposed to high temperatures, should also be tossed.

"You really shouldn't be using last year's sunscreen," said Shah, adding people should be applying it so generously that they should be going through a bottle every one to two weeks.

For Shah, this means using a teaspoon amount on the face, a palm-size amount per arm, and two palm-size amounts per leg for an adult.

Dermatologists typically recommend a broad-spectrum sunscreen with an SPF of 30 or higher.