Dr. Macrene Alexiades-Armenakas, a New York dermatologist, visits The Early Show to talk about ways to make sure your skin is fully protected from the sun.
What is most overlooked by consumers is the quantity to apply and what types of sunscreens really protect the skin against both UVB and UVA sunrays.
Dr. Alexiades-Armenakas explains, "The typical adult needs to apply one ounce, or two tablespoons, of sunscreen to cover themselves from head-to-toe in a single application. Most people apply about half that much."
A family of four, therefore, should go through an 8-oz. bottle in two days.
Dr. Alexiades-Armenakas notes, "Sunscreen needs to be applied 15 minutes prior to going out in the sun and every 1 1/2, to 2 hours later." Also, people must reapply after leaving the water.
Due to slow absorbtion, she stresses that it is important to apply sunscreen at least 15 minutes before the skin is ready to be exposed to sunlight. "It's too late if you're already at the beach," she says.
Dermatologists recommend that in order to protect against UVB rays - the rays that cause the skin to burn - the SPF has to be at least 30. However, SPF does little to indicate how sunscreen protects against the potentially cancer-causing/photoaging rays - the UVA rays. Consequently, sunscreen labels tell only half of the story.
"One needs to look for ingredients that block for UVA," Dr. Alexiades-Armenakas says and notes such products contain physical blockers, like zinc oxide and titanium dioxide, or contain chemical blockers, like parsol 1789 (avobenzone).
Dr. Alexiades-Armenakas explains the physical blockers are superior because they are made of inert metals, so they sit on the skin and don't wear off as quickly as sunscreens that use 'chemical' compounds (parsol 1789). Physical blockers literally reflect the rays of the skin. But since they don't really soak down into the skin, they wash off more easily with sweat and water. The bad news is that they leave a whitish tint.
If you use a product that is chemical-based, you will not get that whitish sheen and it will be more water resistant. The bad news is sunscreens that use chemicals to block UV rays give you less and less protection as the day goes on (your SPF gets lower over time).
Skinceuticals has a physical blocker, so it will protect against UVA/UVB rays but is only available through your dermatologist.