Sunscreen's Magic Number
THE NUMBER YOU NEED TO KNOW, BUT DON'T
Whether you're looking at a bottle of 30 SPF or 70 SPF, you need to apply 2mg of sunscreen per cm2 on your skin to get the advertised protection on a sunscreen bottle. But what does that mean?
If you'll allow us to put on our science hats for a moment, 2 mg per cm2 is the amount of sunscreen that you'd need to apply across your body to get the appropriate level of protection. While the exact amount you'd need to apply depends on your specific body proportions of height and weight, on average, a person would need to use about 1 ounce (30mL) of sunscreen to cover the whole body.
A recent study found that nearly all people only apply a fraction of that amount.
On average, people only apply 1/3 of the proper amount of sunscreen, resulting in 10% of the advertised protection.
It's difficult to know just how much 1 ounce of sunscreen is. Try visualizing the following:
The next time you apply, try measuring 1 ounce of sunscreen.
Chances are you've NEVER put on the correct amount, and you'll probably be surprised at how much you need to be protected!
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