Now that summer’s just around the corner and the sun rays are getting hotter every day, piling on the sunscreen is more important than ever. Of course you should wear it all year round, but when summer comes, we’re all tempted to use a sunscreen with a higher SPF level than we use in winter, and what’s better than SPF 100, right? Well, the FDA doesn’t seem to agree with that. They have proposed restricting the level of SPF that manufacturers can advertise, limiting it to SPF 50+.
Not all companies have complied though. High SPF sunscreens is one of the fastest growing segments of the market, so there’s clearly a huge demand for it. Neutrogena, which makes several sunscreens marketed as SPF 100 and even 110, also claims that this new rule would stifle innovation and prevent companies from trying to formulate more effective sunscreens.
So, what’s the deal with SPF 100?
How SPF works
Before we discuss the problem with SPF 100, it’s important to understand what SPF is and how it works. The SPF number simply determines the amount of time you can stay in the sun without burning. For example, if it takes your skin 20 minutes to burn in the sun, then by using SPF 15 your sunscreen will protect you for 15 times longer. That’s about five hours. Still, dermatologists recommend you apply your sunscreen every 2 hours because your skin can get damaged even if it doesn’t get red and many sunscreen ingredients gradually lose their effectiveness when exposed to sunlight.
The SPF number refers only to UVB protection, so you will need to read the labels carefully to make sure your sunscreen also contains sunscreen agents that can protect your skin from UVA rays, which cause premature aging and cancer. Therefore, SPF is not an indication of the quality of the protection provided by the sunscreen. It just tells you how long you could theoretically stay in the sun without getting a sunburn.
But how much UV radiation is blocked?
It would be logical to assume that a SPF of 30 would double the protection of a SPF 15, and so on, but that’s not how it works. A SPF 15 sunscreen blocks 93% of UVB radiation, a SPF 30 sunscreen blocks nearly 97% and a SPF 50 block 98%. And no sunscreen can protect against all UV rays. Even a SPF 100 will protect only from 99% of UVB rays. So, the amount of added protection you get from bumping up the SPF is minimal.
So, what’s wrong with high SPF numbers?
A high SPF number can lead to a false sense of security. You believe that your skin is better protected and so you’ll be less likely to apply it liberally and retouch it every couple of hours. This will increase the amount of sun your skin is exposed to, which eventually leads to more skin damage and a higher risk of developing skin cancer. In her book, Simple Skin Beauty, Dr Ellen Marmur explains:
“A 1999 study published in the Journal of the National Cancer Institute showed that using higher-SPF sunscreens lead to increased sun exposure. In the experiment, one group was given a low-SPF sunscreen, while the other used SPF 30. The group given the higher SPF spent 20 percent more time in the sun than the other group. Even though it’s wrong-headed, we’re often guilty of spending more time in the sun than we should and not reapplying a sunscreen just because the SPF is 50 or 70. Those are deceptive numbers for sure, and inaccurate – especially if you remember that a higher SPF give you only a fraction more protection.”
What matters is how much sunscreen you apply
Most people never apply the amount of sunscreen that’s needed to reach the level of SPF stated on the bottle (1/2 teaspoon for face and neck, a shot glass for the whole body). And once again, sunscreen math is deceiving. If you apply only half the amount it takes to reach a SPF 100, for example, you don’t get the protection provided by SPF 50, but that of the square root of the SPF: that’s SPF 10! Even lower than the minimum amount of SPF recommend by experts, which is 15. Therefore, always make sure you apply the recommended amount and keep doing so every couple of hours (you can apply it less frequently only if you don’t spend time outdoors).
The Bottom Line
There really is no need to use a sunscreen with a SPF higher than 50. For most people, a SPF 30 will be more than enough. What really matters to ensure that your skin is always protected against the sun rays is choosing a broad-spectrum sunscreen and applying it liberally throughout the day.
What level of SPF do you use?