There are a lot of sunscreen brands, but only two main types: chemical-based and mineral-based. Mineral sunscreens (referred to as inorganic sunscreens since they don’t contain carbon) use zinc oxide and/or titanium dioxide to reflect the sun, says Darrell Rigel, a clinical professor of dermatology at New York University and fellow of the American Academy of Dermatology. Chemical sunscreens (or organic sunscreens since they contain carbon) are more common in the United States and use chemical ingredients like oxybenzone and avobenzone that absorb the sun’s damaging ultraviolet light and transform it into a less harmful red beam.
When I called Rigel, he said both types have their advantages and disadvantages, and that he wouldn’t recommend one over the other. “The best sunscreen is the one you’re going to use,” is how he put it. Still curious, I decided to put them to the test. Here are my results.
Last last month, I worked several 24-hour shifts with a swiftwater rescue team in Northern California (we were standing by for any rescues on a large waterway construction project). I began my shifts at 6:30 a.m. and sat in the sun for about 12 hours in 90-degree heat. On my right arm, I used Banana Boat Sport Performance SPF 30, a broad-spectrum chemical sunscreen. On my left, I used the broad-spectrum Alba Botanica Sensitive Mineral Sunscreen SPF 30. I reapplied each sunscreen every two hours as suggested to me by Rigel and other dermatologists I’ve spoken to previously. To keep the application amounts as similar as possible, I drew a single line across my arm from my T-shirt sleeve to my wrist and rubbed in each one completely, taking care to use only one hand for each arm.
Right away, I noticed that it was much harder to rub in the mineral sunscreen. I massaged my arm for a full minute, but it still had a white residue on top, making my arm look grossly pale. The chemical sunscreen, by contrast, disappeared after just a couple seconds of rubbing. The mineral sunscreen felt thicker and heavier on my arm, while the chemical sunscreen felt oilier. As soon as I started sweating, my mineral sunscreen arm got whiter, and it looked like the sunscreen would slough off if it brushed against anything.
In terms of protection, my mineral arm was red halfway through the first day. By the end of the first day, that arm was crisp, while my chemical arm was a deep tan. On the second day, my chemical arm turned a noticeable red, but my mineral arm was still significantly worse.
Why didn’t the mineral sunscreen work well in my test? Well, here’s the big caveat with those formulas: Mineral sunscreens easily wash off your skin. “They wash off because they are not absorbed [like chemical sunscreens],” Rigel says. “They are just on the surface.” Even though the mineral sunscreen I used was supposed to be water-resistant for up to 80 minutes (a standard Rigel says all sunscreens should hit), it couldn’t deal with my sweat in the California heat.
According to Consumer Reports, which performs a big sunscreen test each year, many mineral sunscreens, just like mine, have not lived up to their SPF ratings. In fact, this year, the mineral sunscreens faired so poorly that none of tested brands made Consumer Reports’ list of recommendations.
But before you give up on mineral sunscreen, know this: Cameron Rokhsar, another dermatologist and fellow of the American Academy of Dermatology who I interviewed for a previous article, said he considers mineral ingredients to be better at protecting your skin since they reflect UV rays instead of absorbing them. The problem seems to be in the application, not the actual ingredients. Also, another Outside writer just tested a slew of mineral sunscreens and found that many are more waterproof than the one I used.
Consumer Reports found that a majority of chemical sunscreens lived up to their SPF ratings, but some still failed. At the Environmental Working Group, which also tests sunscreens, there are concerns that certain ingredients in chemical sunscreens, namely oxybenzone, might cause hormone disruption, but that’s been disputed by dermatologists. There have also been reports of chemical sunscreens causing rashes.
So how the heck do you decide? Here’s some advice from the doctors.
- Rigel and Rokhsar say that regardless of which sunscreen you use, it needs to be at least SPF 30, because anything lower wears off too soon.
- Both doctors also say you need to religiously reapply every two hours, even if the sunscreen has a giant SPF rating (say 50-plus).
- Make sure your sunscreen is broad spectrum so it protects against UVA and UVB rays.
- Use more sunscreen than you think is necessary.
Based on my test, here are my suggestions.
- If you’re going to sweat a lot or be in the water, stick with chemical sunscreens that are rated as water-resistant for 80 minutes.
- If you’re not sweating or in the water, a mineral sunscreen should work just fine.
- Get a sunscreen that you like and will reapply.
Finally, here are some affordable sunscreens that scored near the top of Consumer Reports’ most recent test.