The sun is shining and summer is in full swing. How can we enjoy this much-awaited season while keeping our skin protected from UV rays? We consulted the dermatologists to separate fact from fiction.

If you're in the market for a new sunscreen, check out our expert-approved list of picks. Bonus: you can find them all at the drugstore!

What’s the difference between UVA and UVB rays?

“UVA is known for deeper penetration and its role in skin aging, while UVB is known for its role in burning skin and more directly causing the damage that leads to skin cancers,” says Toronto-based dermatologist Dr. Annie Liu.

Can I use my child’s sunscreen?

Yes, there aren’t any specific ingredients in children’s sunscreen that make it unsuitable for adults, says Dr. Liu. Children’s sunscreens are often formulated with sensitive skin in mind, which can also benefit adults.

How much sunscreen should I apply for proper protection?

About a teaspoon of sunscreen is enough to cover the face and neck, and 2 tablespoons (about a shot glass) is needed for the rest of the body. Remember: You need to reapply every two hours for maximum protection.

Is one daily application of SPF 50 better than applying SPF 30 every two hours?

No. Regardless of SPF, sunscreen no longer works actively two hours after application, says Dr. Liu. So, without reapplying, your SPF 50 won’t be effective all day. Consistency is key.

What’s the difference between SPF 30 and SPF 50?

Sun protection factor (SPF) indicates how well a sunscreen protects against UVB rays. The number itself measures how quickly it would take protected skin to burn compared to skin without sunscreen. It’s estimated that SPF 30 allows about onethirtieth of rays to reach the skin. “SPF 30 blocks about 97 percent of UVB rays, while SPF 50 blocks about 98 percent,” says Dr. Liu.

Photo courtesy iStock Photo

Do I still need sun protection underwater?

Yes. “UV rays can penetrate water,” says Dr. Liu. For proper sun protection while you’re taking a dip, look for the words ‘water-resistant’ on your sunscreen bottle, she says.

Can a visit to the tanning salon give me a ‘base tan’ to protect against UV rays?

Absolutely not, says Dr. Liu. A ‘base tan’ does not provide sun protection and, in fact, “every tan we get is our skin’s way of saying it was damaged from UV radiation.”

Do I need to wear sunscreen indoors?

“UVA radiation can penetrate through glass,” says Dr. Liu. Because these types of rays are involved in accelerating the signs of skin aging, like dark spots and lax skin, it’s recommended to wear sunscreen indoors, especially if you’re working near a window.

Is sunscreen still necessary after 5 p.m.?

In Canada, this depends on the season, says Dr. Liu. “If it’s still daylight, yes. Up to 80 percent of UV rays can penetrate through clouds.” That means even late in the day or in overcast weather, sun protection is essential.

My sunscreen from last year is still full. Can I use it?

“Yes, as long as it’s been stored in a cool place and hasn’t expired,” says Dr. Amy Cao, a Quebec-based dermatologist and fellow of the Royal College of Physicians of Canada. “If it’s expired, definitely throw it out,” adds Dr. Liu. “Your skin deserves the best protection against carcinogenic UV rays that can cause skin cancer and accelerate skin aging.”

What’s better: chemical or mineral sunscreen?

“The best sunscreen is the one that you’ll wear,” says Dr. Cao. Sensitive skin may prefer mineral formulas, while chemical sunscreens are less likely to leave a white cast. What’s most important, Dr. Liu says, is choosing a sunscreen with broad-spectrum protection and an SPF of 30 or more, and applying it properly, which means every two hours when exposed to UV radiation.

Do childhood sunburns increase the risk of skin cancer?

Yes. “One blistering sunburn can more than double your risk of developing melanoma, the deadliest type of skin cancer, later in life,” says Dr. Liu.

If I wear a hat, do I still need to apply sunscreen on my face?

Yes. Most hats don’t provide sufficient sun protection due to the weave density and brim, says Dr. Liu. “For example, a baseball cap doesn’t protect the sides of your face or the back of your neck.”

Can you get skin cancer on your lips?

“I’ve seen many patients with skin cancer on their lips,” says Dr. Liu. “Please use a lip balm with SPF 30+!”

Can a layer of makeup provide sun protection?

“Not unless there’s an SPF listed on the makeup,” says Dr. Cao, and even then, you have to apply enough, which can be difficult to gauge.

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