The Truth About Sunscreen: Understanding Labels & Ingredients

(Last edited July 10th)

I am so excited to share this post about sunscreen with you. I've always had interest on the topic and have done minimal research in the past to answer my own questions. I really dove in the past couple weeks to write this, going through online sources and trying to decipher what is legitimate and what is not. Disclaimer: I am not a dermatologist or an expert on the matter. This post is based on what seems to be the most accurate, up-to-date information, and my conclusions are based on what I have read and my own discernment. Also note that I am not differentiating between sunscreen and sunblock when I say "sunscreen."

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It's always a great feeling when summer arrives in the pacific northwest because the sun finally comes out. But of course we need to be careful because skin cancer is much too common in the U.S., as 1 in 5 people develop it. It's so important to be mindful of sun exposure, but I won't be lecturing you on precautions to take (because you can find that information on the back of a sunscreen bottle). This post is all about one thing that we all heavily rely on (maybe a little too much over other protective measures) to protect us from the sun: sunscreen.

(And before I continue, if you don't use sunscreen because you think you don't need it, think again. The majority of people who get skin cancer are those who are actually less vulnerable to UV damage--people with more melanin. One major reason is because they tend to be less cautious about sun protection. Anyone can get skin cancer. Remember that.)

There are so many different sunscreen and SPF products out there and so much information on the internet about what ingredients you should avoid (I'm sure you've heard of our controversial friend oxybenzone)--it's all a bit overwhelming. That is exactly what inspired me to gather information to give you a comprehensive sunscreen guide. I will explain some science, clear up misconceptions, and tell you what to look for in a sunscreen.

"Broad Spectrum": UVA & UVB

A sunscreen is described as "broad spectrum" if it has active ingredients to protect you against both UVA and UVB rays. UVA is associated with skin aging and long term damage, as it penetrates deeper layers of your skin. UVB is associated with burning, since it affects the top layers of your skin. (If you're wondering which causes tanning, I'm not sure because some sources claim one or the other, so it seems like possibly both). Clearly, both are bad! UVA and UVB both contribute to skin cancer, which is why you can develop it even if you don't burn easily, so be sure to always get a sunscreen that is "broad spectrum."

SPF

SPF stands for Sun Protection Factor. It only tells you about the amount of UVB protection you're getting, since the scale if based off of how long it will take you to burn (but I wouldn't read into that so much). It's important to know that the SPF number is a logarithmic telling of protection, which means that as the number goes up steadily, the percent of UV protection increases more slowly. SPF 15 protects against 93% of UV rays, SPF 30 protects against 97%, SPF 50 protects against 98%, and SPF 100 protects against 99%. As you can see, after SPF 30, there is not much of a difference. The reason most people suggest that you stick to lower SPFs (between 30 and 50) is so that you don't get a false sense of security that can come with a sunscreen. To illustrate how powerful a "false senses of security" can be, I'll illustrate a hypothetical scenario.

Let's say you go into a store to get sunscreen without understanding the SPF scale. You see a product with SPF 30 next to one with SPF 60. You would probably think that SPF 60 would provide you with double the protection of SPF 30, so you get the SPF 60 sunscreen for your beach trip the next day. At the beach, you don't adequately apply the SPF 60 product or reapply it because you're subconsciously comparing it to the SPF 30 that you saw in the store. Before you know it, you get sunburned and wonder how that happened with your SPF 60. The fact of the matter is that there's just about a 1% difference of UV protection between SPF 30 and SPF 60, not 50%!

Most sources recommend a minimum of SPF 30, but besides this recommendation, what SPF you choose is up to what you believe you need. I you have albinism, a family history of skin cancer, or any condition that makes you especially vulnerable, it is recommended that you use higher SPF. Just be mindful to use the same precautions with a high SPF as you would with a low SPF.

Spray-On Sunscreen

I've always stuck to lotion sunscreen rather than aerosol sunscreen because I've heard that they are simply "better." But after researching, I can now explain why some people say this. Spray-on sunscreens are only effective if you use them properly, meaning that you need to make sure that you apply enough and rub it in. According to Harvard Health Publishing, most people only use about one quarter of the needed amount with aerosols; you may need to spray it on area of your body for up to six seconds to get adequate UV protection. As with all types of sunscreen, you should apply 1 once (enough to fill a shot glass) for your whole body with each application. You should also be careful not to inhale spray sunscreen. Besides these concerns, aerosol sunscreen can actually be advantageous in its convenience. Some people may not use sunscreen simply because rubbing in lotion is too much work, so use whatever kind of product you need in order to get your UV protection. My take on lotion vs. aerosol sunscreen is that lotion seems like a safer bet, but if the convenience of a spray means you'll wear sunscreen, then buy the spray.

Chemical vs. Physical/Mineral Sunscreen

If you don't know which of the two you use, it's probably a chemical sunscreen. These are relatively easy to rub in, don't leave your skin looking ashy, and usually include at least two of the following active ingredients: oxybenzone, avobenzone, octinoxate, octocrylene, octisalate, and homosalate. Chemical sunscreens basically work by absorbing UV. Mineral or physical sunscreens tend to be thicker, tend to make your skin look a bit ashy, and include zinc oxide and titanium dioxide as their active ingredients. There are also some mineral sunscreens that don't leave a white cast because they are made of nano particles. (I will discuss nano vs non-nano in the next section). Physical sunscreens work by blocking out UV rays. Also note that "organic" sunscreens are chemical, and "inorganic" sunscreens are physical. Don't be fooled by sunscreen packaging that makes a big deal out of it being "organic." That just means that it's a chemical sunscreen.

If you are comparing chemical and physical sunscreens, it's hard to say which one is "better." "Better" depends on your needs and wants. If you have sensitive skin, opt for mineral. I have also read that mineral sunscreens tend to be less pore-clogging, so you may prefer mineral for your face if you have acne. Besides these concerns, when deciding between which one you should get, I think it's important to consider the application. I admit that in the past I have skipped on using sunscreen because my mineral sunscreen that I had with me was a hassle to put on and would make me look ashy. So application is a downfall to non-nano mineral sunscreens. Also, they have been found to be not as protective as chemical sunscreens because chemical sunscreen products have outscored physical ones in consumer reports. However, you also need to look at the ingredients to decide for yourself which you would rather use.

Ingredients & Safety

What really sparked my interest long ago in researching about sunscreen was hearing from my friend that sunscreen is bad for you (or something like that; memory is fallible). Yeah, you read that right. That day, I was the only person putting on sunscreen before swim practice, and she told me that. Anyways, I was very confused, so I did some shallow research and, after reading some sources, I understood where this claim could have possibly come from. Most of the active chemical sunscreen ingredients out of the 6 listed above have been found in the human bloodstream, and some sources claim that a few of them are also hormone disruptors. However, it is unsure of whether or not these are actually hormone disruptors and are harmful to the body. I have found a lot of conflicting claims on the internet that make it unclear. Additionally, the American Academy of Dermatology Association, the Skin Cancer Foundation, and Harvard Health Publishing of Harvard Medical School say that there is no solid evidence proving these chemical sunscreen ingredients are harmful. (Please feel free to read the Harvard Health Publishing article for elaboration.) While the question of the safety of oxybenzone and other chemical sunscreen ingredients is a valid one, it is still just a question that needs more research to be answered. Because of misinterpreted information and hasty conclusions (like what my friend told me) that get passed around via the internet, moms, friends, etc., people have been scared into not using sunscreen, which is what I believe the 3 sources listed above are trying to combat

For now, we are not quite sure about oxybenzone's effects, but what we know for sure is that the FDA has named zinc oxide and titanium oxide (the two active ingredients of mineral sunscreen) as the only sunscreen ingredients that are "generally recognized as safe and effective" or GRASE. In 2019 the FDA called for more research to be conducted on 12 chemical sunscreen ingredients, including the 6 common ones I have listed above. This means that you can be sure that mineral sunscreens are safe.

And a word on nano vs non-nano mineral sunscreen. You may have seen "non-nano" on a label and wondered why that's significant. Nano is made with nanoparticles, which are defined to be 1 to 100 nanometers (nm) in size. Zinc oxide and titanium dioxide can be dangerous if they penetrate the skin; however, according to Nature Nanotechnology, nanoparticles above 30 nm act as non-nano particles when it comes to safety concerns (i.e., they don't penetrate the skin). It seems that nano sunscreen is widely accepted as being safe for usage. The Australian Therapeutic Goods Administration (TGA) says that we can be pretty sure that nanoparticle sunscreens are safe based on several studies that show that nanoparticles do not penetrate the skin. From my understanding, the (very) small amount of uncertainty comes with the vague definitions of nano and non-nano sunscreen (in regards to exact particle size and how much of the product is made of what particles), as the FDA does not define them. Since nano sunscreens are generally seen as being safe, you might be still If you're wondering why products will flaunt their "non-nano" formula on their packaging. I'll get into that in the next section. And if you are wondering how you can tell the general difference between the two if a product doesn't specify, you can be pretty sure that it is nano if the product is labeled as "invisible" or "clear."

That was a lot of information, but in short, if you have sensitive skin or acne concerns use mineral sunscreen, and if you are at all concerned about the safety of chemical sunscreen or nano mineral sunscreen (if you're pregnant or something), go for non-nano mineral sunscreen. If you cannot stand to use it, though, don't hesitate to use a nano mineral or chemical sunscreen. At the end of the day, remember that protecting yourself from the sun is your number one priority. So if you're in a situation in which you must choose between using oxybenzone or going without sunscreen, I'd go for the oxybenzone.

"Reef Friendly"

When I see "reef friendly" on a product, it definitely makes me want to buy it over another. This is exactly why brands use it as a marketing strategy. Don’t assume that a product that claims to be "reef friendly" absolutely does not harm reefs or any wildlife. There are no guidelines for when a product can claim that. Check the active ingredients to make sure that there is no oxybenzone or octinoxate because these have been found to bleach and harm coral, so you can be sure that they are not reef safe. Some places including Hawaii and Key West have even banned the use of sunscreens with these ingredients. As for other active sunscreen ingredients, levels of the chemicals have been found in the ocean, but it is unsure if their presence affects wildlife. More research needs to be done,

Nano titanium dioxide and zinc oxide have also been proven to be toxic. However, non-nano titanium oxide and zinc oxide are safe for marine life, or I should say that they are definitely the safest sunscreen ingredients. So if you are swimming in open water, use a sunscreen without oxybenzone, octinoxate, or nanoparticle mineral sunscreen ingredients, and if you want to be sure that you are using an absolutely reef friendly product, go for a non-nano mineral sunscreen.

"Sport" or "Active"

When a sunscreen says "sport" or active," that means it is water resistant. Generally, water resistant sunscreens need to be applied after 40 minutes of swimming or sweating, and "very water resistant" sunscreens need to be applied after 80 minutes. Also note that there is no such thing as water proof sunscreen. If you're going to be swimming or sweating, be sure to use water resistant sunscreen so that it doesn't slide right off your skin so quickly.

SPF in Makeup

If you'd prefer to use a foundation with SPF instead of sunscreen, be smart about it. Recall that SPF only protects you against UVB rays, so if you're looking for a foundation or BB cream or what not, make sure it's broad spectrum. If it doesn't say, check the active ingredients. Generally, if it contains zinc oxide then you are good to go because this ingredient protects against both UVA and UVB. If it lists chemical sunscreen active ingredients, I'd just do a quick internet search because certain ingredients need to be used in conjunction to get broad spectrum protection.

An important thing to remember is that no matter what form your UV protection is in, it will only last two hours max in the sun, so don't rely on your foundation with UV protection to work throughout the day. I haven't found an answer on how to get UV protection all day with makeup on besides reapplying your foundation or powder unfortunately. I would suggest using traditional sunscreen instead of makeup with UV protection if you know that you will be in the sun all day. If you do want to wear foundation, use other precautions like wearing a sun hat.

However, if you aren't in the sun all day, you may not need to constantly reapply throughout the day. I have read that sunscreen breaks down with sun light, not time. This makes sense since chemical sunscreens work by turning UV light into heat (but note that I haven't read if there is a difference in this between chemical and physical sunscreens). However, be cautious with this statement. Sunscreen also breaks down quite fast with sweat and water, and UVA rays can penetrate through windows. Generally, though, you don't have to worry about reapplying your daily face sunscreen throughout the day if you'll just be indoors.

Because of the reapplication issue, be careful to not rely on foundation with UV protection. However, the UV protection can be a why not bonus for your foundation if you don't wear sunscreen on your face anyways (even though you should!). So if you ever want a foundation with UV protection for certain occasions, find one that's broad spectrum and a high enough SPF (remember, SPF 5 doesn't do much; aim for at least 15). And if you'll be in the sun, be prepared to reapply or wear a hat.

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I learned a lot from writing this, so I hope this helps. I know it's a lot of information, but don't overthink when you're trying to decide on a sunscreen to get. Remember that at the end of the day it's important to get a sunscreen that you will want to use and actually use. My main goal was to inform you so that you can be deliberate in your sunscreen-related decisions. Let me know if you have any questions.

Stay safe!