physical vs. chemical spf

As you’ve probably heard by now, sunscreen use is absolutely essential to healthy skin. When used correctly, it helps reduce the risk of skin cancer, skin damage, and even premature aging. 

When choosing a sunscreen, you can opt for either a mineral or chemical formula - and whatever your preference, there are strong pros and cons for each type. Here’s what we know about them.

SPF or sun protection factor

Let’s start with the basics! SPF or Sun Protection Factor is a measure of your sunscreen’s ability to protect your skin from UVB rays, which are responsible for sunburns. The SPF number on a sunscreen tells you how long the sun’s UVB rays would take to redden or burn your skin if you applied the sunscreen as directed, compared to the amount of time it would take without the sunscreen!

chemical SPF

Actives include: oxybenzone, avobenzone, octisalate, octocrylene, homosalate. These are all organic or carbon-based compounds.

How it works: chemical sunscreen actives absorb UV rays and convert them into heat, which is then released from the skin. They act as a protective shield by absorbing radiation before it has a chance to penetrate! 

One thing to note: chemical formulas require at least two different actives to protect skin against both UVA and UVB rays - a chemical like avobenzone to block UVA rays, a chemical like oxybenzone to block UVB rays, and so on.

Pros: chemical sunscreens generally feel more lightweight and less noticeable on the skin.  They’re compatible with all skin tones and it’s easier to develop water resistant formulas that are pleasant to use. 

Cons: chemical sunscreens typically take around 20-30 minutes to start protecting your skin.  Additionally, more people experience sensitivities to chemical sunscreen actives compared to mineral actives. 

There are some concerns about the body potentially absorbing chemical SPF actives and research has shown that some chemical actives do harm reefs and ocean life. Research is still being conducted on the impact of different sunscreen actives on coral reefs and the environment, but Hawaii has currently banned the use of sunscreens containing oxybenzone and octinoxate.

mineral SPF

Actives: titanium dioxide (TiO2), zinc oxide (ZnO). These are minerals (usually made in a lab) that are ground into fine white particles or powder.

How it works: physical or mineral sunscreens sit on the surface of your skin and absorb, scatter, and reflect UV rays away. They absorb approximately 85-95% of rays and scatter or reflect 5-15% of rays. 

To get more specific about how the mineral sunscreen absorption process works, the Clinical Guide to Sunscreens and Photoprotection states, “being small particulate crystals, these materials are semiconductors with high bandgap energy. UV radiation is absorbed by elevating an electron from the valence to the conduction band.”

Pros: physical or mineral sunscreens naturally provide broad spectrum protection, or protection from both UVA *and* UVB rays. They can be better for sensitive or breakout-prone skin, because they’re less likely to cause reactions or irritation. Zinc oxide even has some anti-inflammatory properties that help soothe the skin, which is why it’s often used in diaper rash creams.

Both of the main active ingredients used in mineral sunscreens (zinc oxide and titanium dioxide) are certified as GRASE, or Generally Recognized as Safe and Effective, by the FDA. 

Physical or mineral sunscreens also offer immediate protection (as soon as they’re applied) and are considered safer for the reefs and ocean, though the term “reef-safe” is still somewhat controversial

Cons: mineral sunscreens tend to appear chalky and are more prone to leaving a white cast, as their active ingredients are a white powder. While mineral formulations have come a long way,  it’s unfortunately not possible to create a completely sheer mineral sunscreen. In order to work for every skin tone, mineral sunscreens usually need to be tinted or incorporate chemical actives to create a more sheer application.  

Mineral formulas also tend to have a thicker consistency and feel more noticeable on skin after application. Additionally, when sweating or getting wet, physical or mineral sunscreens may cause “milky” drops on the skin. 

Mineral sunscreen is still not 100% reef or ocean safe, though it is considered the “better” option. 

so, which sunscreen should I use?

Whichever you will wear! There are pros and cons for each type of sunscreen, but the most important piece of advice we can offer is to choose one and make sure you wear it every day! 

According to the American Academy of Dermatology, “skin cancer is the most common form of cancer in the United States, and nearly 20 Americans die from melanoma — the most dangerous form of skin cancer — every day, per the Skin Cancer Foundation. The No. 1 cause of melanoma? Exposure to natural and artificial ultraviolet (UV) light; the same light you get from tanning beds and the sun’s rays.”

we hope you found this helpful! if you have any questions, feel free to shoot us a DM on Instagram or email!