Truths, Lies, and Sunscreens

Medical Author: Nili N. Alai, MD, FAAD
Medical Editor: Melissa Conrad Stöppler, MD

What is the best sunscreen?

Overall, the safest and most effective sun-protection products are pure zinc and/or titanium-based sunblocks. These two ingredients have been around a long time and boast great safety data. The ideal sunscreen blocks both ultraviolet A and B (UVA and UVB) rays, is stable, doesn't break down in the sun, and doesn't get absorbed through the skin.

Is there any difference between sunscreens and sunblocks?

Physical sunscreens like zinc oxide and titanium dioxide are sunblocks; they physically (like a brick wall) block both UVA and UVB rays. Besides these two, all other sunscreens are chemical-based sunscreens. Chemical sunscreens like oxybenzone, avobenzone, PABA, etc., are generally colorless and have special ingredients that filter and reduce UV rays. Not all sunscreens effectively block UVA as well as UVB rays. The chemical sunscreens break down with sun exposure and may need more frequent application.

When should I use a sunscreen?

Dermatologists recommend that everyone use sunscreen of at least SPF 15 or greater every day, year-round. If you plan to be in the sun more than 20-30 minutes a day, you should wear sunscreen of at least SPF 30. Even on cloudy days, about 80% of the sun's rays pass through the clouds. Nowadays, so many moisturizers, lotions, and makeups have sunscreen built in that it doesn't make sense to use any products that don't contain sunscreen. It just makes it so mush easier. I recommend, for example, if you wear any foundation, that there be at least an SPF 15 built in. If not, you may want to change brands.