We all know that wearing
sunscreen is an anti aging must, but Dr. Nadim Shaath a consulting scientist for SkinCeuticals, says that protection against UV rays alone won’t keep you from looking like a Shar Pei. “Even the best sunscreens on the market are only able to block 55% of the UV rays that come in contact with your skin,” he says. Before you decide to adopt Twilight-worthy sun aversion tactics, Dr. Shaath recommends layering an antioxidant serum (think 10-percent vitamin C) under your sunscreen. “In addition to battling UV damage, antioxidants fight against the aging effects of free radicals and infrared radiation,” he says, pointing out that neither of these can be blocked by sunscreens.

We chatted with Dr. Shaath to get more sun care tips and boost our UV IQ. Here’s what we learned…

Sunscreen tip: How much sunscreen do you need to apply?

“Most people don’t use enough product,” says Dr. Shaath who explains that you need a shot glass worth of sunscreen to apply over your body and dollop the size of a ping-pong ball on your face. “If you only put on half the amount, then you’re only getting half the UV protection,” says Shaath.

Sunscreen tip: How often do you need to reapply sunscreen?

Not re-applying sunscreen properly is the main reason people don’t get adequate SPF protection. According to Dr. Shaath, if you’re outside frolicking (be it at a pool-side barbeque, boating at the cottage or just sitting on a patio with friends) you need to reapply your sunscreen roughly every two hours to ensure you’re blocking the UV rays. And that means fully applying your sunscreen, not just slather lotion on the areas that look a bit pink.

View our top picks for facial sunscreen here.

To find out what your reommended SPF really is and learn the difference between UV rays read on to the next page…

Sunscreen tip: What level of SPF do I really need?

“For everyday use, I wouldn’t recommend going below an
SPF 30,” says Dr. Shaath. Your ideal value depends on the level of UV exposure and your complexion (fair skinned individuals typically need a higher level of protection). If you’re going to be outside for a while Dr. Shaath says some simple arithmetic can find your sunscreen solution. “If you wear an SPF of 30, then you maximize your sun exposure at 300 minutes,” says Dr. Shaath. Not only can you use this to pick your optimal SPF level, but it can help remind you when/how often you need to re-apply.

Sunscreen tip: What is the difference between a physical and chemical blocker?

A physical blocker (like zinc or titanium dioxide) work like a mirror and actually “bounce” or reflect UV light off the surface of your skin. Conversely a chemical blocker absorbs the UV rays on the surface of your skin. But, as Dr. Shaath points out, the most important thing is that your sunscreen has a broad-spectrum formulation (since the measure of UV protection only refers to the amount of UVB rays that the sunscreen blocks). UVA filters include: Avobenzone, Parsol, Mexoryyl XL, and Tinosorb S and Tinosorb B.

Sunscreen tip: What is the difference between UVA and UVB?

UVB rays , which only account for 5% of the rays that hit your skin are the rays that either
allow you to bronze or burn. Conversely, UVA rays effect the deeper layers of your skin and increase the number of dark spots, fine lines and wrinkles. Translation? UVA filters are crucial.

Sunscreen tip: Do I really need to wear an SPF everyday?

The simple answer is yes. UV exposure doesn’t just come from the sun (shocking, we know). “Even your computer screen gives off a low level of UV radiation,” says Shaath. A few hours in front of your MAC may not do any permanent damage, but if you’re in the office day after day, week after week, month after month, year after year…you get the idea. The point is, UV damage can accumulate over time and increase the rate at which your skin ages. The solution? Wear an SPF of 30 daily.

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