Like all dermatologists, Stefani Takahashi, M.D. is vocal proponent of sunscreen. While every HMF patient should wear sunscreen everyday, she believes summer is a great time to review skin protection basics—especially for active children.

TYPES "The typical drugstore has dozens of varieties of sunscreens, but they all fall into one of two categories: chemical or physical," says Dr. Takahashi, who is board-certified in both dermatology and pediatric dermatology.

Chemical sunscreens work by absorbing the UV rays before they reach the skin, while physical sunscreens reflect or scatter UV rays. Physical sunscreens contain compounds such as titanium dioxide and zinc oxide that are micronized to work in a lotion or cream.

SPF The Sun Protection Factor (SPF) is calculated by comparing the number of minutes it takes to sunburn unprotected skin to the number of minutes required to burn protected skin. (However, SPF measures UVB protection only. A system of quantifying UVA protection is under development.)

Since many people are not aware of their own burning threshold, an SPF of at least 15 is a good choice—provided it’s used correctly.

DOCTOR’S ORDERS "Many people skimp on the sunscreen," says Dr. Takahashi. It takes approximately one ounce of sunscreen to cover an average adult wearing a bathing suit. "Imagine a shot glass filled with sunscreen—that’s how much you should use for each full body application," she says.

"Also, it’s best to apply sunscreen 20 to 30 minutes before going outside so the sunscreen can bind to the skin," she says. "Regardless of the SPF you’re using, you need to reapply another full ounce approximately every two hours. If you’re sweating profusely or have gone swimming, reapply more often."

She notes that "water resistant" and "water proof" sunscreens remain effective when subjected to water or heavy perspiration for just 40 and 80 minutes, respectively.

WHAT’S HOT? Sun protection continues to evolve. Johnson and Johnson combined two proven sunscreens, avobenzone and oxybenzone, in a stable base that remains effective for a longer period of time. They block the UVB rays (as do all sunscreens) plus the UVA rays. Look for this combination protection in sunscreens by Neutrogena (as Helioplex) and Aveeno (as Active Photobarrier Complex).

L’Oreal USA, the American arm of the international cosmetics giant, received FDA approval for Mexoryl, an ingredient in European sunscreens. Mexoryl is now available in L’Oreal’s La Roche-Posay sunscreens and provides broader, longer-lasting UV coverage.

KIDSTUFF More than half of a lifetime’s sun exposure occurs during childhood. That’s why it’s so important to teach sun safety to your children, including the proper use of sunscreen.
If your child has sensitive skin, a chemical-free physical sunscreen made with zinc oxide or titanium dioxide may be the best choice.
Remember to take special care with newborns and young infants. "Infants under six months of age should not be exposed to direct sun for prolonged periods," she says. She advises parents to protect infants with appropriate clothing and by staying in the shade, especially during the peak hours between 10 a.m. and 3 p.m.

COVER UP While everyone knows about sun protection that comes in a tube or bottle, UV fashion, especially for children, is a new concept to many people.

Clothing by companies like Coolibar, Solumbra, and Tuga Sunwear are made of tightly woven fabric that blocks UV rays. In contrast, the typical white t-shirt offers only moderate protection from UV radiation.

"Seeking shade, covering up, and using sunscreen are the cornerstones of sun protection," says Dr. Takahashi. "Parents need to protect their own skin and help their children develop good habits."