Welcome to our Derm Knows Best series, in which a dermatologist takes over the Good Skin blog to share his expertise on important skin care topics. This time we hear from board-certified dermatologist Dr. Karan Lal, DO, MS, FAAD.
Read on as he explains the differences between chemical and mineral sunscreens, and how to choose the best SPF for your skin. The importance of daily sun protection. Let's start with the basics.
Every day, whether it’s sunny, rainy, snowy or cloudy, skin is exposed to ultraviolet rays (also known as UV rays). Not only are UV rays considered carcinogenic, but they can also cause skin damage such as premature wrinkles, hyperpigmentation, and more.
Many factors affect the amount of light that reaches your skin at any given time (eg: do you work outdoors or spend more time indoors with the blinds drawn?), but regardless, it's virtually impossible to completely avoid these rays. This is where sun protection comes into play.
Types of sunscreen. The most important thing when choosing a sunscreen is to find one that you want to apply (and reapply) every day to thoroughly protect your skin from sun damage. However, there are two types of SPF: chemical sunscreen and physical sunscreen.
Chemical sunscreen. If you see ingredients like avobenzone, oxybenzone, octinoxate, octyl salicylate, octocrylene, or homosalate, you may be using a chemical SPF. After application, these ingredients are absorbed into the skin. When UV rays hit the surface of the skin, they are converted into heat and released back into the atmosphere.
One of the great things about chemical sunscreen is that the effectiveness of the formula is less likely to be affected by sweating and swimming over time because it is absorbed. This also means chemical sunscreens tend to be less visible, especially on darker skin tones, reducing the likelihood of white spots appearing.
However, research shows that ingredients in chemical sunscreens are not only absorbed into the skin but also enter the bloodstream, becoming potential triggers for people with sensitive skin or those with inflammatory conditions like eczema.
"The results of this publication indicate that when sunscreen is applied to the skin, blood concentrations of the active ingredients can be measured with just one application of all six tested active ingredients and all formulations," the FDA said.
But don't throw away your tube just yet. Although these test results were released in 2020, the FDA is still investigating whether these ingredients may cause side effects in the body.
Mineral sunscreen. While chemical sunscreens are absorbed into the skin, physical sunscreens (as opposed to the term "mineral sunscreen") primarily remain on the skin. When physical sunscreen is applied, UV rays "bounce" off the skin's surface and back into the atmosphere.
Most physical sunscreens are made from zinc oxide (found in Guards Up Daily Mineral Sunscreen) and titanium dioxide, two ingredients considered "safe and effective for use in sunscreen" by the FDA.
Another benefit of many mineral sunscreens like Guards Up is that they're formulated with iron oxide, an ingredient known for preventing blue light damage (like dark spots) caused by tech devices like phones, computers, and tablets.
Physical sunscreens, on the other hand, are known to leave a white cast, especially on darker skin tones. This is because zinc oxide and titanium dioxide are naturally white and do not disappear easily into the skin.
However, many physical sunscreens now use micronized or non-nano zinc oxide (meaning they have smaller molecules), which can effectively reduce whitening.
One of the great things about chemical sunscreen is that the effectiveness of the formula is less likely to be affected by sweating and swimming over time because it is absorbed. This also means chemical sunscreens tend to be less visible, especially on darker skin tones, reducing the likelihood of white spots appearing.
However, research shows that ingredients in chemical sunscreens are not only absorbed into the skin but also enter the bloodstream, becoming potential triggers for people with sensitive skin or those with inflammatory conditions like eczema.
"The results of this publication indicate that when sunscreen is applied to the skin, blood concentrations of the active ingredients can be measured with just one application of all six tested active ingredients and all formulations," the FDA said.
But don't throw away your tube just yet. Although these test results were released in 2020, the FDA is still investigating whether these ingredients may cause side effects in the body.
Mineral sunscreen. While chemical sunscreens are absorbed into the skin, physical sunscreens (as opposed to the term "mineral sunscreen") primarily remain on the skin. When physical sunscreen is applied, UV rays "bounce" off the skin's surface and back into the atmosphere.
Most physical sunscreens are made from zinc oxide (found in Guards Up Daily Mineral Sunscreen) and titanium dioxide, two ingredients considered "safe and effective for use in sunscreen" by the FDA.
Another benefit of many mineral sunscreens like Guards Up is that they're formulated with iron oxide, an ingredient known for preventing blue light damage (like dark spots) caused by tech devices like phones, computers, and tablets.
Physical sunscreens, on the other hand, are known to leave a white cast, especially on darker skin tones. This is because zinc oxide and titanium dioxide are naturally white and do not disappear easily into the skin.
However, many physical sunscreens now use micronized or non-nano zinc oxide (meaning they have smaller molecules), which can effectively reduce whitening.
Which sunscreen is best for your skin?
Bottom line: You should use the sunscreen that works best for your skin. Do your research and read the ingredient list to make the best decision for your skin and body.
I generally recommend chemical sunscreen for active people who spend a lot of time outdoors, sweating, or in the water. For people with sensitive skin, eczema, melasma, or hyperpigmentation, I recommend a physical sunscreen that contains iron oxide to not only protect your skin from the sun, but also from other external factors . However, don’t forget to use half a teaspoon daily and reapply every two hours.
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