Get Sunscreen Savvy

Fact #3: Higher SPFs can be beneficial, but that doesn’t mean you’re off the hook from reapplying.
Used to be, you were hard-pressed to find anything above an SPF 30. Now, sunscreens come in SPFs all the way to up 100. Do they really make a difference? Turns out, they can. To understand why, though, you first have to understand exactly what SPF really means:

“SPF is a measure of the amount of time you can stay in the sun before getting sunburned from UVB exposure,” explains Dr. Schweiger. For example, if you normally start to redden or burn after five minutes in the sun, wearing an SPF 30 means it will now take you 150 minutes (5 minutes x 30 SPF) to burn. This sounds great in theory, but the reality is a different story: “In reality, sunscreens are applied too thinly, they get sweated off, and they break down over time, so they never give you quite the protection they’re supposed to,” says Dr. Schweiger.

Starting with a higher SPF can be beneficial since you’ll have a higher level of protection from the outset, but remember—that doesn’t mean you get a free ride as far as re-applying. “Every sunscreen loses its effectiveness over the day,” says Dr. Kauvar. “Reapplication is just as important as putting it on in the first place.” The rule of thumb: Reapply every two hours, and always reapply after sweating or swimming.

MORE: 6 Ways to Outsmart the Sun

Fact #4: When it comes to sunscreen, antioxidants are your best friend.
Some research indicates that as chemical sunscreens break down, they can increase the amount of free radical activity on your skin—however, the evidence is inconclusive. “The study that examined this question was performed on engineered skin tissue, and tested individual ingredients rather than sunscreen products, so specific conclusions can’t be drawn,” explains Dr. Kauvar.

Still, it’s better to be safe than sorry—all the dermatologists we talked to recommended choosing a sunscreen that’s fortified with antioxidants over one that’s not. The best antioxidant ingredients to look for: Vitamin E (alpha tocopherol) and vitamin C (L-ascorbic acid). “Vitamin C has been shown to help combat free radicals and boosts immunity of skin cancer fighting cells,” says New York City dermatologist Francesa Fusco, M.D.

If your sunscreen doesn’t include either of these beneficial ingredients (or even if it does), think about layering an antioxidant serum underneath for extra anti-aging power. “Green tea polyphenols are the most stable, and one study showed they protect against sunburn,” explains Dr. Amy Wechsler, YouBeauty Dermatology Advisor.

A green tea serum to try:
Topix Replenix Serum CF, $52