For those of us without a medical degree, understanding the fine print on a sunscreen bottle can be confusing. Use our decoder when you're stocking up this summer. By Cara Litke Sullivan, REDBOOK
Active ingredients: This is the part of the label that lists the type of sunscreen used. If it's a chemical formula, the active ingredient is often avobenzone (considered the most effective); others are octocrylene, octisalate, and homosalte. If it's a mineral sunscreen, the active ingredient is titanium dioxide, zinc oxide, or both.
The SPF number: Two things to know when you're eyeing this magic number: 1. It indicates only how well you're protected from UVB rays, the ones that cause a sunburn. It doesn't apply to your protection from UVA rays, which cause wrinkles and skin cancer. 2. Only an SPF 30 or higher sunscreen that's labeled "broad-spectrum" protects from UVA and UVB rays. So don't kid yourself with SPF 8-if you wear anything less than 30 when you're out in the sun, you basically have on nothing at all.
Related: 100 Colorful Looks Under $100
Directions: What you won't see here but should know: If it's a cream, you need to slather a shot-glass's worth on your body and a teaspoon on your face every two hours. If it's a spray, mist in zigzaggy motions till you gleam, then rub it in-even if it says you don't have to. And don't forget to reapply!
Inactive ingredients: Here's where you'll find everything else that's in the formula. If you have sensitive skin, make sure the words hypo allergenic and fragrance- and PABA-free are on the front or back label. Prone to breakouts? Look for oil-free and non-comedogenic.
Related: The Best Celeb Hairstyles for Every Length
The expiration date: Once a sunscreen bottle is opened, it's good for two to three years, regardless of the expiration date listed-if it's stored in a dark, dry place in between seasons. If you're not sure when you bought it, toss it and buy a new one. But keep in mind: If one bottle of sunscreen lasts you the entire summer, you're not using enough!
If you have small children and are worried about chemicals… Use a mineral sunscreen. They're chemical-free, so even if your kid licks it off you, there's absolutely no risk of illness (which is why sunscreens made for babies and kids are usually mineral formulas).
Related: 40 No-Fail Beauty Shortcuts
If you plan on swimming: New FDA labeling rules clarify how long a sunscreen lasts when you're in the water. Now, a formula may be labeled "water-resistant," meaning it protects you for up to 40 minutes, or "very water-resistant," which means you're covered for up to 80 minutes. (They've done away with the term "waterproof," because nothing really is.)
Wait 30 minutes, seriously. You know where it says "apply 30 minutes before sun exposure"? Believe it. Chemical sunscreens take 30 minutes to work. If you're in a rush, mineral ones are effective right away.
More from REDBOOK: