3 Things You Should Know About Sunscreen

The sun is our friend, except when it is not. On a boiling summer day, just minutes of outside exposure can turn our life-giving solar system’s star into a scorching threat. According to the National Institutes of Health, older adults are at a greater risk for developing skin cancer than any other age group. Prolonged exposure to the sun’s ultraviolet radiation is the number one cause of this ailment, the most common form of cancer. The solution: sunscreen

For more than 70 years, sunscreen has provided protection against the threat of the sun. But for many, some aspects of sunscreen are a mystery. For example, what does SPF mean? Luckily, we are here to help! Here are three things you need to know about sunscreen.

Most people do not apply enough sunscreen.

According to Dr. Steven Wang of the Skin Cancer Foundation, the conditions under which sunscreens are tested are not always the same as those under which they are used. “To evaluate SPFs, testers apply two milligrams of sunscreen per square centimeter of skin. But in everyday life, most people apply from only 0.5 to one milligram per square centimeter of skin. Consequently, the actual SPF they achieve is approximately one-third of the labeled value.”

Most people do not apply enough sunscreen.

The way to combat this? Apply a thick layer of sunscreen, and be sure to reapply every few hours. Higher SPF sunscreens are effective, but they are also more costly. There’s no reason you can’t squeeze every dollar out of your bottle of SPF 30.

Speaking of high SPF, what is the difference between SPF 30 and, say, SPF 100?

Not very much. SPF measures the amount of protection against UVB rays (the rays that cause sunburn). SPF 30 sunscreen blocks 96.7 percent of said rays. SPF 50 blocks 98 percent, and SPF 100 blocks 99 percent. The difference between SPF 30 and SPF 100 is just over two percentage points worth of protection.

Bottles of Sunscreen

Save your money and buy the mid-tier SPF sunscreens. Don’t take it from us, either. Listen to Dr. Barbara Gilchrest, a dermatology professor at the Boston University School of Medicine, who was quoted in this New York Times article as saying, “[SPF 100 sunscreen] is really in my opinion tremendous overkill.”

Sunscreen, particularly American sunscreen, does not leave your skin fully protected!

Remember how we mentioned UVB rays? Unfortunately, they are just one of two potentially skin-damaging forms of ultraviolet radiation. As our good friend Dr. Wang notes, “SPFs mainly measure UVB protection. Individuals applying high-SPF sunscreens may not burn…but without UVA-screening ingredients they can still receive large amounts of skin-damaging radiation.”

Sunscreen, particularly American sunscreen, does not leave your skin fully protected!

Sunscreen is a magnificent tool to protect your skin from the sun, but don’t treat it like a cure-all. It’s not. Limit your sun exposure, apply sunscreen thoroughly and repeatedly, and wear sun protective clothing. Enjoy the sun, but stay protected, too.

Last updated: 03.20.2018

Disclaimer: This content is for informational purposes only and it is not meant to be relied on as medical advice, diagnosis, or treatment. Consult your physician before starting any exercise or dietary program or taking any other action respecting your health. In case of a medical emergency, call 911.

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