While a lot of skincare experts will tell you that an SPF 30 will do just fine, I disagree wholeheartedly.
In theory, here’s why: An SPF of 30 allows 3.3% of rays through, an SPF of 50 allows 2% of rays through, and an SPF of 100 allows 1% of rays through. A difference of 2.3% between SPFs 30 and 100 doesn’t sound like a lot, but when you consider that SPF 100 is 330% stronger, or 3.3x stronger, that’s certainly a significant difference in theory.
But recent studies reveal that SPF 100+ may be significantly more effective than 50+ in practice. (Oh, the difference between in practice, and in theory!)
In Practice: The Higher the Better
According to a study published in the Journal of the American Academy of Dermatology, SPF 100+ sunscreen was 3-5 times more effective in protecting against sunburn than SPF 50+ sunscreen in actual use conditions. (Even higher than in theory!) The study took 199 men and women who wore both SPF 50+ and 100+ sunscreens simultaneously during activities, with no use restrictions other than designation of the treatment area. Erythema was clinically assessed on the day following exposure. Comparative efficacy was evaluated through bilateral comparison of sunburn between treatment areas and erythema score, as evaluated separately for each treatment area.
“Didn’t matter your skin type, age, or gender, the SPF 100 was always better,” Darrell Rigel, clinical professor of dermatology at New York University Langone Medical Center and an author on the study, which was funded by Johnson & Johnson Consumer Inc., tells Allure. When it came to redness (erythema), 40.7% of the SPF 50 group had redness following sun exposure, as opposed to just 13.6% of the SPF 100 group.
And the results were more significant when it came to sunburn. “People were about 10 times more likely to burn on the SPF 50 side than the SPF 100 side,” Rigel says. Given the results, the researchers concluded that SPF 100 is “significantly more effective in protecting against sunburn than SPF 50.”
The reason for this? Consumer compliance. Remember that SPF is calculated using 2.0 mg per square centimeter of skin — about 1/3 to 1/2 a teaspoon for the average face, and that’s reapplying every four hours. Most people don’t use near that amount of sunscreen, nor do they reapply as frequently as they should. The result is that people are getting a lot less protection from SPF 30 than they think, and certainly a lot less than when using SPF 100+.
How to Apply SPF the Right Way!
The short answer? Buy a quarter teaspoon (or half teaspoon), fill it up, and use it on your face twice per day.
A 1997 study by Stokes et al. in Cosmetic Dermatology found that most users achieve a mean SPF of between 20 and 50 percent of that expected from the product label, because they do not apply the sunscreen as thickly as in laboratory conditions (2 mg/square centimeter of skin, or 30 mL of sunscreen over the average human body). Users need to be aware that sunscreens need to be applied at least 30 minutes before sun exposure, and, for proper protection, re-applied every two to three hours from the initial application, or sooner, if being exposed to the water.
When I have the time, I apply a chemical sunscreen first. I wait for 30 minutes. The reason? Chemical sunscreen ingredients like oxybenzone, avobenzone, Mexoryl SX, and Mexoryl SL take about 30 minutes to absorb into the skin properly. Once absorbed, the chemical sunscreen ingredients will transform the majority of UV light that hits the skin into non-damaging forms of energy — heat or non-UV light. It sounds like some pretty cool science fiction work, but it’s true — that’s how it works!
On the other hand, it’s best if as little UV light hits your skin as possible in the first place. So I love, love, love to apply physical sunscreens like zinc or titanium oxide OVER TOP of the chemical sunscreens once the chemical sunscreens have been given at least 30 minutes to dry. The zinc or titanium oxide acts as a shield that blocks the majority of UV light from hitting your skin, so I’m a huge fan of using both formulas!
The Best High SPF Sunscreen
Neutrogena Age Shield Sunscreen SPF 110: A physics professor of mine used to always say, “The numbers don’t lie, and neither do I.” Well, I don’t know about him for certain, but numbers surely don’t lie. And the sky-high rating on Neutrogena Age Shield Sunscreen SPF 110 indicates this has more UVB protection than a pair of blue jeans (which is SPF 99). That said, this is not a cosmetically-appealing sunscreen. It is very, very white. I don’t mind using it unless I have a big business meeting or presentation (after all, everyone knows I’m a skincare fanatic; ultra-heavy sunscreen goes with the territory). But if I have a big business meeting or presentation, I won’t use it. If thick, white, visible sunscreen doesn’t bother you, reach for Neutrogena Age Shield Sunscreen SPF 110. Applied liberally, it’s the best sunscreen out there for burning that I could find.
Afterwards, because I don’t like UV light hitting my face at all, I tend to use foundation or powder with a zinc or titanium oxide over top. Right now I’m loving IT Cosmetics Your Skin But Better SPF 50+, with a high concentration of zinc and titanium oxide. I apply the Neutrogena Age Shield like a primer first, and then use the IT Cosmetics product next. My skin looks great so far this summer, and it’s been a hot one, with me outside more frequently than usual, chasing a 16-month-old around the park! But it’s been good, and I think it’s because of my commitment to higher SPF, as well as the layering of formulas.
Read the complete list HERE.