Sunscreen Basics: UV Filters, How It Works & What It DOESN’T Do

Sunscreen Basics: UV Filters, How It Works & What It DOESN’T Do

If I had to pick the greatest love of my life at this moment, my answer is definitely my dog. He’s my child. My mother, my partner, and all of my friends are totally fine with being number 2 to him. In the realm of skincare, sunscreen is the equivalent to my dog. Retinoids, cleansers, toners can all be less accepting than my family is of being second, but that will never change. With May being the Skin Cancer Foundation’s Skin Cancer Awareness Month, it feels like the right time to lay out some basics.

I want to make a disclaimer right off the top that I am not a dermatologist or a  chemist. My education is all in the realm of psychology and sociology, so I am not the person to look to for an in-depth breakdown of all the science behind sun protection. I’m here to follow derms and chemists and pour over research papers so you don’t have to if that’s not your thing. Please bring any serious concerns regarding sun protection and/or skin cancer to your medical professional(s).

In the realm of skincare, sunscreen is the greatest love of my life. And with May being Skin Cancer Awareness Month, it feels like the right time to lay out some basics.


What Sunscreen Does

You’ve probably heard of UVA rays and UVB rays, but what are they? They’re the two wavelengths of UV rays that our bodies are exposed to from the sun that sunscreen is made to protect against. I always remember UVA = aging and UVB = burning. UVA rays as the ones that get deeper in the skin and can cause premature aging (among other things). UVB rays on the other hand don’t get as deep and are primarily responsible for sunburns. After A and B, we get to C, which in this scenario stands for skin cancer, which both UVA and UVB rays contribute to.

The function that sunscreen fulfills is that it reduces the amount of UV rays that our skin is exposed to. They sit on top of your skin and in some cases scatter or reflect the UV rays, but they mostly absorb UV rays and convert them into something less harmful, like heat. This in turn will help prevent sun damage, sunburns, and mostly importantly, your risk of skin cancer. Everyone over the age of 6 months should be using one, but it’s especially vital if you are using skincare products that can increase your sun sensitivity, like a retinoid or exfoliant.


What Sunscreen DOESN’T Do

I could, and probably will, go on a much longer rant at some point about all the ridiculous things people claim sunscreens do but actually don’t. The fact of the matter is the current science does not support many common concerns about sunscreen people share online. There’s a lot to dive into with each of these concerns people raise, but here’s a quick rundown of things you don’t need to be stressed and scared about.

There is not evidence to support that sunscreen disrupts the hormonal activity in your body. I’ve seen people claim sunscreen enters your bloodstream and can do everything from impact fertility to disrupt thyroid function. There is no proof of this.

There also isn’t any evidence that sunscreen actually encourages cancerous growths. It is extremely unlikely you’re giving yourself cancer by applying sunscreen.

sunscreen filters

Most concerning, there’s “evidence” from the EWG (y’all know how I feel about them) people love to quote that states sunscreens don’t protect you from UVA and UVB rays and there is no strong evidence connecting UVA/UVB exposure and increased rates of melanoma. I promise y’all that this is not the case.

There are way more sunscreen myths out there, but these are the most common ones I’ve heard every summer for the last few years. For the love of all that is dewy, please do not be scared of sunscreen.


What Sunscreen Options There Are

This is a common sentiment among the skincare community online, and I couldn’t agree with it more: The best sunscreen is the one you’ll actually wear. There’s a lot of options as far as sun protection goes nowadays, but there are two major categories all of our sunscreen filters fall under.

sunscreen filters

1. Physical (aka Inorganic) Sunscreen Filters

Physical sunscreen filters, aka inorganic filters, are the stereotypical white, thick, paste type sunscreens you see in older movies and TV. Zinc oxide and titanium dioxide are the only two members of this family, and they’ve been around for a very long time. There’s a misconception inorganic filters reflect UV rays away from our skin instead of absorbing them, but we know now that this is not the case.

These filters are also marketed as being better for sensitive skin, but zinc oxide in particular has astringent and antiseptic properties that can actually feel drying and irritating on the skin. That doesn’t mean they will definitely irritate or dry out your skin. It just means they’re not inherently “better” for sensitive skin.

Traditionally, sunscreens with these filters end up leaving a white cast on your skin and aren’t the easiest to spread out. Thankfully there’s been a lot of advances in cosmetics that help mitigate these issues, but it’s still an inherent property  of inorganic filters.

2. Chemical (aka Organic) Sunscreen Filters

Chemical sunscreen filters, aka organic filters, are pretty much every other type of sunscreen filter you see in products on the market. They also work by absorbing UV rays and prevent them from getting to your skin. These are often loved for their cosmetic elegance. We’re talking low to no chance of white cast and much better spreadability on the skin.

These frequently get advised against because of their potential for irritation or for being “toxic.” As I always say, chemicals are not something to be scared of (we’re literally made of them) and are not inherently negative. With the variety of organic filters available, especially in Europe and Asia, there’s a definite chance you’ll run into one your skin doesn’t agree with. That’s just the nature of the situation when more choices are available. Do not feel like you must avoid these filters for any reason or that physical/organic sunscreen filters are somehow “better” than their chemical/inorganic counterparts.

So now that we have the foundation down, in the next part of this sunscreen basics series, I’ll discuss application (and reapplication!) techniques.


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