Differences Between the SPF Levels

Differences Between the SPF Levels May 9, 2020 / by Complete Family Dermatology Team

Sun Protection Factor (SPF) is the degree to which sunscreen will protect the skin from the damaging rays of the sun. There are so many options for the strength of sunscreen on the market, so it can be challenging to decide which is the best to protect skin from sunburns that may cause skin cancer. 

The Broad Spectrum of SPF

Sunlight has two different rays that can harm the skin. Ultraviolet light with a longer wave is UVA, while short-wave ultraviolet light is UVB. UVA light can damage the thickest layer of the skin and is known to lead to some cancers, premature aging, and wrinkles. UVB damages the surface layer and is also known to be responsible for skin cancer. A broad-spectrum sunscreen will work to block both harmful rays from causing damage. 

Physical and Chemical Sunscreens

Broad-spectrum SPF sunscreens work by having two different types of sunscreens work together. The physical sunscreens sit on the skin and protect it by acting like a shield. Ingredients such as zinc oxide and titanium dioxide create physical protection on the skin to block some rays. Chemical sunscreens absorb the rays, preventing them from penetrating the skin. When chemical and physical sunscreens work together, they broaden the protection from both rays of the sun.  

What Do the Different Levels Mean?

A sun protection factor is a number that lets you know how it will take for the sun to burn the skin when using that level of sunscreen. When using an SPF 50 sunscreen as directed on the label, the user can expect it would take 50 times longer to burn compared to not using any sunscreen. When evaluating which sunscreen level is best for you, think about how long it takes you to burn. If your skin starts to redden after being in the sun for only 10 minutes, an SPF of 15 protects the skin for 150 minutes if it is applied correctly. A higher SPF does not mean more protection, but there are some notable differences.
  • SPF 15 offers protection from 93% of UVB rays.
  • SPF 30 offers protection from 97% of UVB rays.
  • SPF 50 offers protection from 98% of UVB rays.
  • SPF 100 offers protection from 99% of UVB rays.

Using and Applying Sunscreen

There is a proper way to apply and use sunscreen to get the best protection from the SPF level. At least 20 to 30 minutes before being outside, apply at least two tablespoons to the exposed areas of the body. The face alone needs a large dollop to be protected adequately. Apply carefully and be sure to include commonly missed areas, such as the ears, the back of the neck, and the tops of the feet. Be generous with the amount of sunscreen used, as sunscreen is often underused.Wearing sunscreen may create a sense of security that makes forgetting about the sun and sunscreen possible. No matter the SPF level, all sunscreens must be reapplied every two hours. A person who opts for an SPF of 50 and who typically won’t burn the first 30 minutes of sun exposure may feel they have several safe hours in the sun. Furthermore, it is recommended to reapply sooner after swimming, drying off with a towel, and if sweating.  

Sun Protection Strategy

Sun protection goes beyond the proper use of sunscreen on both cloudy and sunny days. A sun protection strategy should include seeking shade whenever possible and wearing wide-brim hats and clothing designed to protect the skin from the rays. Also, a lip balm with SPF protection and sunglasses meant to block UV rays add protection.  It can be challenging to decide which is the best to protect skin from sunburns that can cause skin damage. At Complete Family Dermatology, Dr. Geoff Basler and Brent Behrens, PA-C encourage everyone to wear sunscreen, no matter the weather outside, and reapply every two hours or less. If you are looking for more information about sun protection, feel free to contact our office.

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