Health library

SPF (Sun Protection Factor) is often a confusing term that can also be misleading as bigger numbers do not equal better results. Walk-In Clinic provider Aprill Graham, NP-C, explains how to properly choose and use sunscreens in order to prevent avoidable skin damage.

By Aprill Graham, NP-C, GRH Walk-In Clinic 

SPF (Sun Protection Factor) is often a confusing term that can also be misleading as bigger numbers do not equal better results.  Understanding how to properly choose and use sunscreens is very important in preventing avoidable skin damage.  Using sunscreen correctly is critical to vital skin health and preventing sunburns and skin cancers.  Choose a sunscreens that is Broad-Spectrum.  This means they protect against the sun’s damaging ultraviolet A and B rays (UVA and UVB). 

The number of the SPF gives us a time line on how long it will take for your skin to burn when using the sunscreen product exactly as instructed versus if you were not using any sunscreen.  SPF measures the degree of protection against UVB and UVA absorption.  So if you used a sunscreen with an SPF of 30, it would take 30 times longer for your skin to burn than if you had not used any sunscreen at all.  The confusion often comes with people believing that the higher the number of SPF, the better protection, but studies shows that products with SPF of more than 50 provide very little increased protection.  

Rather than get focused on a specific SPF number, it is most important to follow the basic rules of sunscreen:

Apply sunscreen to your entire body BEFORE putting on your swimsuit or clothing so you don’t miss any hidden areas.  You should put the sunscreen on at least 30 minutes before you are exposed to the sun.  It is very important to re-apply sunscreen about every two hours.  If you are swimming or heavily sweating, you should re-apply more often and put on another dose immediately after getting out of the water.  A general rule of thumb is to use about one ounce of sunscreen per application. An easy way to measure this is to apply a golf ball sized amount of sunscreen.  Be sure to apply to the top of the head, ears, neck, tops of feet and other easily missed places.

The Skin Cancer Foundation states: It is important not to rely on high-SPF sunscreens alone. No single method of sun defense can protect you perfectly. Sunscreen is just one vital part of a strategy that should also include seeking shade and covering up with clothing, including wide-brimmed hats and UV-blocking sunglasses. 

Remember to use sunscreen both before and during sun exposure to help prevent painful sunburns and long term skin damage including skin cancers.  

Aprill Graham, NP-C is a provider at the GRH Walk-In Clinic.