We all know that SPF is essential for sun protection, but what is it? And how does it work?

SPF stands for Sun Protection Factor. SPF is a measure of how well a sunscreen protects your skin from Ultraviolet B (UVB) rays, the kind of radiation that causes sunburn, damages skin, and can contribute to skin cancer. SPF is not meant to help you determine how long you can be exposed to the sun without getting sunburned.

Most people apply way less sunscreen than needed for adequate sun protection. When you use half the amount of sunscreen required, you only get a square root-worth of the SPF protection. For example, if you apply half of the recommended amount of a 30 SPF sunscreen, you will only get about 5 SPF-worth of protection.

To protect yourself from the damaging UVB rays, be sure to apply about two heaping tablespoons of sunscreen to exposed areas of the body before you head outdoors.

How well does your sunscreen protect you?

• SPF 15 sunscreen blocks 93% of UVB rays
• SPF 30 sunscreen blocks 97% of UVB rays
• SPF 50 sunscreen blocks 98% of UVB rays

• Take care of your skin. Find a dermatologist in your area.