Sunscreen 101

By on June 1, 2010, in Beauty Knowledge Center, Cosmetics, Skincare

Sunscreen is essential to protect against ultra violet rays that contribute to skin aging, eye damage, immune system suppression and skin cancer. But a recent survey by the American Society for Dermatologic Surgery (ASDS) uncovered that while 94% of Americans know that prolonged sun exposure can cause skin damage, only 20% wear sunscreen on a daily basis. Here’s a crash course in UV rays and sunscreen that will hopefully encourage you to stay safe in the sun every day.

Get to Know Your Rays

There are three types of UV rays:

  1. UVA rays

These are the rays that make up the large majority of our exposure to the sun. UVA rays cause skin damage (like wrinkles) and contribute to skin cancer. Many people mistakenly believe a UVA tan, frequently called a base tan, helps protect our skin from the sun. Don’t be fooled! A UVA tan merely provides a darker skin color and a false sense of security.

  1. UVB rays

Most UVB rays are absorbed by the ozone layer, but those that pass through can have a serious affect. These rays cause eye damage, including cataracts, immune system suppression and contribute to skin cancer. UVB rays are also responsible for most sunburns.

  1. UVC rays

UVC rays are the most dangerous type of ultraviolet rays. These rays are completely absorbed by the ozone layer and do not reach the earth. Whew!

Sun Protection Factor

So what does that SPF number on the bottle really mean? SPF means sun protection factor. The SPF numbers on a product range from as low as 2 to as high as 70. This rating measures the sunscreen’s defense against UVB rays. An SPF number is calculated by comparing the time needed to produce a sunburn on protected skin to the time needed to produce a sunburn on unprotected skin. The higher the SPF rating, the better the sun protection.

To figure out how long you can stay in the sun, use this equation:

Minutes to burn without sunscreen x SPF number = maximum sun exposure time

Of course this equation assumes that you’re applying the proper amount of sunscreen. In the real world, the average user applies less than half of the recommended amount, which is 1 ounce (2 tablespoons) of sunscreen applied to all exposed areas 30 minutes before you go outside. Sunscreen should be reapplied at least every two hours, after swimming or excessive sweating. We know it’s a hassle, but your skin will thank you in the long run!

Types of Sunscreen

Most dermatologists recommend the use of a “broad spectrum” sunscreen. These are formulated to protect against both UVA and UVB rays. And why not get 2 for 1?

Under the broad spectrum umbrella, sunscreen can be divided into chemical and physical sunblocks. Chemical sunscreens absorb the UV rays before they damage your skin. Avobenzone, Octylcrelene, Oxybenzone and Mexoryl are all common chemical sunscreen ingredients. Physical sunscreens reflect and divert UV rays before they even get to your skin. And there are some sunscreens that contain agents of both. Common physical sunscreen ingredients include Titanium Dioxide and Zinc Oxide.

Physical sunscreens are particularly useful for individuals with sensitive skin. They are gentle enough for everyday use, and because they contain no chemicals, they rarely cause skin irritation. Physical sunscreens can be packaged as sprays, gels or lotions – companies like Colorescience have even found ways to provide broad spectrum protection inside your makeup. Colorescience Sunforgettable is a sheer mineral powder with SPF 30 that allows sunlight to pass through while still intercepting both UVA and UVB rays. It’s lightweight, portable and self-dispensing, perfect for travel and touchups on-the-go.

Chemical sunscreens are composed of a variety of active agents because no single chemical ingredient can effectively block the entire UV spectrum. Chemical sunscreen provides the advantage of going on clear and staying invisible without the white cast associated with some physical sunscreens.

With so many choices available, it’s easy to be overwhelmed. Test out different types until you find the one that works best for your skin. The most important thing to remember about sunscreen is to always use it!