The Surprising Connection Between the UW-Madison and Sunscreen

AP Images, Dave Martin

By Christina Lorey

July 20, 2023

You’re probably using the wrong SPF, and you’re definitely not alone.

DID YOU KNOW? The SPF sunscreen scale was created in Wisconsin.

After his residency at the University of Michigan, Derek Cripps joined the UW Department of Dermatology in 1965.

In the early ’70s, he started studying why some sunscreens were more protective than others, and in 1974, he created the SPF ratings scale. The FDA adopted it, and Cripp’s scale became the American standard.

According to the FDA, SPF (sun protection factor) measures how much ultraviolet radiation, or solar energy, it takes for protected skin to sunburn. Contrary to popular belief, SPF isn’t related to the amount of time you spend in the sun.

Sunscreen 101

True or False? SPF 50 is almost twice as protective as SPF 30.

While this sounds like it should be true, it’s false. The fact is, the higher the SPF, the smaller the difference becomes. While SPF 30 blocks 97 percent of sun rays, SPF 50 blocks 98%. Anything higher than that will cost a lot more, without providing much more protection.

And that’s just one of the misconceptions people have about sunscreen. It’s summer fair season, so we wanted to share a few recommendations from doctors at UW Health to save your skin and save you money:

Tip #1: Choose lotion or creams over spray. They provide more consistent and longer-lasting protection. The skincare experts at Good Housekeeping tested 62 sunscreens picked their 14 favorites for your body and face.

Tip #2: Expensive is not always better. As long as the sunscreen is “broad spectrum” (meaning it protects against UVA and UVB rays), is water-resistant, and has an SPF between 30 and 50, it’ll do the job.

Tip #3: Reapply more frequently than you think. UW Health recommends lathering on one ounce (approximately a shot glass size) of sunscreen 15-30 minutes before going in the sun. Then, reapply after your first 30 minutes outside, and again every two hours after that.

Tip #4: Look at the expiration date, but not too closely. Sunscreen doesn’t suddenly stop working. Doctors say it’s effective for at least three years, which is usually a lot longer than its marked expiration date.

MORE: 3 Tricks to Mak e Your Sunscreen Last Longer

Author

Christina Lorey

Christina is an Edward R. Murrow-winning journalist and former producer, reporter, and anchor for TV stations in Madison and Moline. When she’s not writing or asking questions, you can find her volunteering with Girls on the Run, the Pancreatic Cancer Action Network, and various mental health organizations.

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