Banner Health Services  

Are higher SPF sunscreens worth it?

Dr. Mark Gimbel  

Mark Gimbel, MD, is a general surgeon at Banner Gateway Medical Center in Gilbert, Ariz.

Question:  Recently I’ve seen sunscreens with extremely high SPF numbers ranging from 50 all the way to 100.  Are these higher SPF sunscreens really better for me or am I just as protected wearing a sunscreen with 30 SPF?

Answer:  With so many high SPF sunscreens available on the market today, picking the right sunscreen can be challenging for many people due to misconceptions regarding the effectiveness of different SPFs. 

The SPF number, or sun protection factor, indicates the percentage of UVB (Ultraviolet-B) rays that will be prevented from penetrating the top layer of skin where burning occurs. 

Sunscreens with SPF 15 already block 92 percent of UVB rays, while SPFs of 30 and 40 block 97 percent and 97.5 percent of UVB rays respectively, according to the National Cancer Institution.  This means that when using a sunscreen with an SPF above 40 your protection increases by less than 2 percent since no sunscreen exists that blocks 100 percent of UVB rays.

It is important when choosing a sunscreen with your desired SPF value that it is “broad-spectrum” meaning that it also protects from UVA rays.  UVA rays penetrate lower layers of the skin and can cause aging effects such as wrinkles as well as increase the rate of melanoma – a more serious type of skin cancer.  If your sunscreen does not protect against UVA rays, the lower layers of your skin are susceptible to damage.  If worrying about SPF numbers is still too confusing, choosing a sunblock (physical sunscreen) containing zinc oxide or titanium dioxide is another good option.  These safe, inorganic compounds are capable of diffracting 100 percent of ultraviolet rays, but spread on as a thick paste.

As long as you use a broad-spectrum sunscreen or sunblock, you should be adequately protected when using an SPF of 30 or above if it is applied correctly.  It is important to apply sunscreen generously to all exposed skin at least 30 minutes before you head out into the sun, ensuring complete absorption by your skin, and continuing to reapply every two hours for maximum effectiveness.

Reviewed August 2010

Page Last Modified: 04/26/2012
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