Published on: August 20, 2020
What's the difference between sunscreens and antioxidants?
You've always heard antioxidants are photoprotective, so why aren't they classified as sunscreens? I'll answer that question and more here.
Let’s talk about sunscreens first. There are two types of sunscreens: physical and chemical. And, there’s a difference in how they work to protect skin from UV rays. We’ll start by looking at physical sunscreens.
How Physical Sunscreens Work
Remember Chief Brody in Jaws? Do you remember his white nose? Yep, that’s a physical sunscreen.
Zinc oxide and titanium dioxide are both physical sunscreens intended to sit on top of the skin, and they act by reflecting UV rays off your skin, which keeps those rays from penetrating into the skin where they can damage cells. Since zinc and titanium are both minerals, physical sunscreens are also called mineral sunscreens.
Even though they’re referred to as physical sunscreens, there’s still a chemical component to the way they block UV. I’ll mention this again later, but I won’t bore you with the chemistry of it here (although if you want to read more, check out this link).
Before we talk about chemical sunscreens, let’s take a step back for a second and look at how UV rays can damage skin.
How UV Rays Can Damage Skin
UV rays can damage skin in one of two ways:
- The highly energetic ray can hit DNA causing damage directly to the DNA strand. Simply enough, this is referred to as direct UV damage.
- The UV ray can also generate free radicals within skin cells, and these free radicals can cause DNA damage. This is known as indirect UV damage because the UV ray itself doesn’t cause the damage, but rather, it generates a free radical that causes the damage.
How Chemical Sunscreens Work
Chemical sunscreens react with UV rays to form free radicals and heat. Now, that sounds really bad (our cells may not be getting direct DNA damage from UV, but free radicals can cause indirect DNA damage), however, the idea is that chemical sunscreens sit on the surface of our skin, above the dead skin cells, so those free radicals would not reach our living cells as long as that sunscreen isn’t absorbed.
Common chemical sunscreens are: oxybenzone, avobenzone, octisalate, octocrylene, homosalate, and octinoxate.
How Are Antioxidants Different Than Sunscreens?
Rather than react with the UV rays, antioxidants destroy free radicals, or rather, they absorb free radicals offering protection from indirect DNA damage by soaking up free radicals.
While physical and chemical sunscreens are most effective sitting on the surface of our skin and work by blocking UV rays (physical sunscreens) or reacting with UV rays to form something else (chemical sunscreens), antioxidants protect our body from the effects of UV rays, specifically free radicals.
I mentioned earlier, but it’s worth mentioning again: chemical and physical sunscreens are designed to sit on the surface of the skin. That’s where they’re most protective for our skin. However, chemical sunscreens are often absorbed into the skin and nano-particle physical sunscreens have also been shown to absorb into the skin, and that’s a problem.
You’ll notice from the diagram above that chemical sunscreens generate free radicals, and while that’s fine sitting on the outside of our body where the sunscreen is in contact with our dead skin layer, that’s a HUGE problem when the sunscreen is absorbed and is in contact with our living skin layers. Multiple studies show that chemical sunscreens actually increase the amount of free radicals in skin tissue, and this is why I avoid them.
Physical sunscreens are a better option, however, more and more companies have moved to nano-particle zinc oxide and titanium dioxide because those leave less of a white cast on the skin. And, the problem with nano-particles is that they can be absorbed by the skin.
While physical sunscreens technically work by reflecting UV light back off the skin, I didn’t mention the rest of the story.
Zinc oxide and titanium dioxide can also react with UV rays, just like chemical sunscreens, and just like chemical sunscreens, these physical sunscreens can also generate free radicals and other reactive oxygen species (ROS) when they react with UV light, and while that’s fine sitting on the surface of your skin, it’s not what you want going on in your living skin layers.
So, if you opt for a physical sunscreen, non-nano is the best choice, white film and all.
Okay, so, what about antioxidants?
Think of antioxidants kind of like a sponge, they soak up free radicals near them, but they can only soak up so many before they become saturated and have to be rejuvenated (or like a sponge, squeezed out & dried) before they can soak up more free radicals. Many anti-oxidants help rejuvenate each other.
For example, glutathione, a naturally occurring antioxidant in the body, can rejuvenate a Vitamin C molecule that’s spent (technical word for this is oxidized) converting it back to its antioxidant state so that it can soak up more free radicals.
And, many antioxidants also naturally occur within our bodies. Coenzyme Q-10, melanin, alpha lipoic acid, and glutathione are all made by our body. Vitamins C & E are common in foods.
The beauty of our body making its own antioxidants and getting antioxidants in our diet is that these antioxidants are available to help protect skin cells from free radical damage (the effects of UV) when we’re out in sunlight.
However, since these antioxidants can be rapidly depleted when we’re bombarded with sunlight AND because antioxidants do not offer protection against direct UV damage to DNA, it’s important to:
- apply antioxidants topically & frequently when outdoors
- use photoprotective clothing or non-nano physical sunscreens
Why antioxidants don't have SPF Ratings
Lastly, if you’ve ever wondered why products containing antioxidants don’t list an SPF (sun protection factor), here’s why: since antioxidants don’t technically block UV rays, you won’t find a sun protection factor (SPF) listed on products rich in antioxidants. Antioxidants only protect from the effects of UV and don’t stop UV rays from penetrating the skin. As for SPF, well, by now you know I like schematics so here’s another one:
Also, SPF only applies to UVB rays and not UVA rays unless the sunscreen specifies broad spectrum.
Which is better? Antioxidants or sunscreens?
I really feel the choice of sunscreen, antioxidants, or both is one you have to make for yourself, and above all, protective clothing and shade is hands down THE best choice.
I always like to couple protective clothing and shade with antioxidant protection, but again, that’s me, and don’t be surprised if you see a future post about the best non-nano physical sunscreens just in case you choose to incorporate sunscreens into your sun protection.
In the next post in this series, I’ll share more about antioxidants – both dietary and topical including one that will surprise you. In the meantime, go (safely) enjoy some sunshine!
About the Author
Brandy's a formulation scientist and self-proclaimed health geek who loves hiking, gardening, bird-watching, and body boarding.
Her struggle with acne during her teens and 20s led to a holistic and healthy approach to skincare, embracing skin as an organ to be loved and cared for rather than a canvas to wage war on.
Since 2008, she's been developing all-in-one products for a simple routine at home, & Rain Organica started when her backpacking friends asked for a portable skincare routine to keep their skin healthy & happy on and off the trails.
You can try Rain Organica for yourself with The Essentials Kit, a complete skincare routine in just 3 steps.
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