What Type Of Sunscreen To Use, How Often To Reapply & Other Things You Need To Know

Should I apply sunscreen every day?

According to Ahluwalia, there are no days off for wearing sunscreen — not even on cold or rainy days when the strength of the sun isn't particularly evident.

"The most important advice that I give to all my patients is that 365 days a year, you should wear sunscreen," she says. "The sun's rays go through cloud cover. They go through on rainy days. They reflect off the snow. So it's really important to wear sunscreen every single day."

What type of sunscreen should I buy & what's the best SPF?

Not all UV rays are the same. For instance, Ultraviolet A (UVA) has longer wavelengths and is linked to skin aging, whereas Ultraviolet B (UVB) features shorter wavelengths and are the rays that cause sunburns, according to the Skin Cancer Foundation. To protect yourself against both, look for sunscreens that have "broad spectrum" on the label.

"As a general rule, you want a broad spectrum sunscreen with at least an SPF 30" — which, if applied thoroughly, will protect your skin against most of the sun's rays, according to Ahluwalia.

She also recommends sunscreen that contains a blue light filter.

"There's more evidence now that blue light causes oxidative damage to the skin which can lead to more signs of aging and brown spots," Ahluwalia says. "So that's another reason to wear it every single day."

How much sunscreen should I use?

Let's put it this way: You're better off applying just enough sunscreen correctly than going overboard, but missing spots. As it turns out, the rule of thumb is actually a rule of fingers.

"For the face, we say a 'Two-Finger Rule.' So you put the sunscreen in two lines on your index and middle finger, and that's how much to apply to your face and neck," Ahluwalia says. "And then for the body, the right amount is a shot glass amount.

"If you're using the right amount, and you're spreading it thoroughly, then that's probably all you need."

How often should I reapply sunscreen?

It's not enough to only apply sunscreen at the start of the day. Ahluwalia says to reapply sunscreen after swimming or sweating, and every couple of hours as a general rule.

What type of sunscreen should I use on my face?

Not only does your face experience the most year-round exposure (unless you own a high-SPF balaclava) but its skin is already quite sensitive to begin with.

"Often, my patients invest in a sunscreen that contains higher quality ingredients and ingredients that are less prone to breakouts or irritability issues for the face and the neck," Ahluwalia says.

Generally, you can be a little less selective with sunscreen for your body since the skin is less sensitive — though you'll want to find a sunscreen that best suits your needs.

How early before working out should I apply sunscreen?

If you're planning on any sort of sweaty or wet activity — think jogs, hikes and swimming — it's a good idea to give your skin a little extra time to absorb the sunscreen.

"Usually, just as a general rule of thumb, I say apply 15 minutes before exposure," Ahluwalia says. "But the truth is, a lot of the sunscreens work as soon as you apply them these days."

For those looking for extra peace of mind for their beach day, look for the "water resistant" and "very water resistant" labels; these sunscreens hold their SPF for 40 and 80 minutes of submersion, respectively.

Do I need to use sunscreen if I have darker skin?

The short answer is, yes. Though people with light complexions burn easier than those with darker complexions "sunscreen is important for people of all different photo types, from the very lightest to the very darkest," Ahluwalia explains.

She adds: "Certainly, people with fair skin will burn easier, and they're more predisposed to skin cancer... (but) people with more melanated skin are more prone to disorders of pigmentation and uneven skin tone."

Plus, even if you're less likely to suffer a sunburn than your pal, you're both equally at risk of sun damage triggering the premature signs of aging.