Given the choice, I will ALWAYS choose a mineral sunscreen instead of a chemical one.
That means I look for products that contain zinc oxide, or a combination of zinc oxide and titanium dioxide.
Yes, even though they're hard to find—and even harder to formulate well. Mineral SPF has a bad rep for giving a white cast to the skin (although that's becoming less of an issue with some of the newer products), and there's also that whole nanoparticle thing to worry about. I get the issues about minerals, I really do.
But even so—I still think that mineral filters (a.k.a. physical sunblocks) are a better choice than chemical (also confusingly called "organic") sunscreens.
The most common chemical SPF ingredients include oxybenzone, avobenzone, octisalate, octocrylene, homosalate and octinoxate, usually found in combination. And there are some very legit reasons for avoiding them.
Here's why you might want to make the switch from chemical to mineral sunscreen:
1. Chemical sunscreen absorbs into your bloodstream.
Mineral sunscreen is the safest because it acts like a physical block. It sits on top of your skin, and works by reflecting away the sunlight.
Chemical sunscreen, on the other hand, actually penetrates* right into your bloodstream. It works by absorbing the UV rays and converting them into heat that is released through the skin. But did you know that chemical ingredients such as oxybenzone can linger in our bodies for five days after a single application? It has been detected in breast milk, blood and urine. This study found it in the urine of 96 percent of 6 to 8 year old girls.
I don't know about you, but if I have the choice, I'd much rather avoid products that enter and stay in my body. Plus, these researchers discovered something else: chemical sunscreen ingredients can act as penetration enhancers, helping any other chemicals you use to enter the skin.
* An exception is encapsulated octinoxate, found in Cyberderm Every Morning Sun Whip SPF 25. Encapsulation makes it act like the large molecules of mineral filters, which remain on the outer layer of dead skin instead of absorbing into the body. Because this technology is more expensive, you won't find it in mass-market sunscreens.
2. Chemical sunscreen is linked to hormone disruption.
One of the biggest concerns with chemical sunscreen is that it might mimic, block or alter hormone levels—also known as endocrine disruption. Although there are no definitive answers YET, these researchers found that oxybenzone, homosalate and octinoxate affected thyroid and reproductive hormones in multiple animal and cell studies. This year, an Endocrine Society study reported evidence that eight chemical sunscreen ingredients interfere with human sperm cell function. So it's not a stretch to conclude that chemical SPF could be affecting our fertility.
There is no evidence for any hormone-disrupting effects from using zinc oxide or titanium dioxide.
3. Chemical sunscreen can cause cell damage.
Another problem with chemical sunscreen is that it's linked to oxidative damage, thanks to inadequate protection from UVA rays. No doubt you've heard the words "free radicals" before, and know they're enemy number one in terms of skin aging. But what does that term really mean? It refers to highly reactive oxygen molecules—chemical byproducts that are generated from exposure to environmental factors such as smoking, pollution, and (you guessed it!) UV radiation. Free radicals encourage premature aging by attacking cell structures and degrading collagen and elastin fibres.
Because some sunscreen chemicals are not very photostable, they can amplify free radical production, releasing these harmful byproducts when they absorb UVA energy. In fact, this study found that some chemical filters may cause more free radicals to form than no sunscreen at all!
What's even more disturbing is that chemical sunscreen could cause gene mutations. Several studies (see here, here, here and here) have found that certain SPF ingredients generate DNA damage in human skin cells upon UV exposure. That means potential carcinogenicity. SCARY.
To suppress this cascade of free radical formation, you need a sunscreen with strong UVA filters. Zinc oxide is the best option because it offers broad-spectrum protection against both UVA and UVB rays. (Don't rely on titanium dioxide, as it's inadequate on its own for UVA protection.) Check out this table, via the U.S. Environmental Protection Agency, to see how the ingredients compare (I wish Health Canada had such a user-friendly chart!):
4. Chemical sunscreen may trigger skin reactions and acne.
If you have sensitive skin or are prone to allergies, mineral sunscreen is definitely the way to go. (Although I always say that it's good to err on the side of gentleness with your skin, in general, no matter what your skin type.) Chemical sunscreens are much more likely to trigger contact dermatitis; the symptoms can include rashes, itchiness, blisters and swelling. Oxybenzone is the worst culprit, but avobenzone, octinoxate and octocrylene are known to cause allergic skin reactions, too.
There are no cases of skin allergy from zinc oxide or titanium dioxide.
If you're acne-prone, mineral filters are also best, because they're less comedogenic (pore-clogging) than chemical ingredients. Zinc oxide and titanium dioxide can even be slightly drying on the skin, making them ideal for normal to oily types—or anyone who wants to avoid a greasy feel. (Note: You'll of course want to check the other ingredients in any mineral formula for comedogenicity.)
5. Chemical sunscreen doesn't protect you right away, and needs frequent re-application.
Remember how I said that mineral sunscreen sits on top of your skin, whereas chemical sunscreen must be absorbed? Well, that means the minerals will start protecting you from the sun immediately, as soon as you apply them. With chemical SPF, you need to wait about 20 minutes before you're considered protected.
Many chemical sunscreens are also unstable, so they don't work for very long. They start to break down quickly in the sun, losing their effectiveness—which is why dermatologists are so adamant that we re-apply them often. Even though there are options that won't mess up your makeup, let's face it: re-application is kind of a pain!
In contrast, mineral sunscreen lasts longer, provided you're not getting wet or excessively sweaty (which might make it wear off). Every two hours is the "golden rule" for sunscreen re-application, but if you did a thorough application of mineral sunscreen in the morning and then spent most of the day indoors, then you're probably still adequately protected (as Dr. Cynthia Bailey suggests here). However, to be on the safe side, I would still re-apply mineral SPF when outdoors for long periods of time.
Natural Sunscreen Recommendations
Here are a few of the mineral sunscreens in my rotation. Keep in mind that the higher the zinc oxide concentration, the better. I also avoid any products with polyunsaturated oils, as they, too, interact with radiation to cause cellular damage. I'll be sharing more product recommendations soon in a separate post!
- Cyberderm Simply Zinc Sun Whip SPF 25: The best, most elegant formula I've found. It's a whopping 22 percent zinc oxide in an olive oil base with anti-aging peptides and NO silicones. Also non-whitening and free of nanoparticles.
- Badger All Season Face Stick SPF 35: You have to rub this in to get rid of the white layer (and it's probably not great for darker skin tones), but I love the VERY short organic ingredients list, and high (22.5 percent) zinc oxide content.
- Attitude Little Ones Mineral Sunscreen SPF 30: This is 20 percent non-nano zinc oxide with a short, safe ingredients list (no silicone, no fragrance). It's affordable and great on face or body.
- Juice Beauty SPF 30 Oil-Free Moisturizer: Based on the oil-free natural ingredients list and 20 percent zinc oxide content, this is a winner.
- Aveeno Baby Sensitive Skin Mineral Sunscreen SPF 50: One of the few mineral options at the drugstore, with 8 percent titanium dioxide and 3 percent zinc oxide. It's by no means perfect (there's not enough of the active ingredients to offer full protection), so I use this on my body—not face.
Are you on board the mineral sunscreen train with me? I hope these points have at least given you some food for thought.
Obviously, some sunscreen is better than no sunscreen—if the alternative is a burn!—and the best sunscreen is the one you will actually wear. (Which is why I included both mineral and chemical options here.)
But given the many safety concerns I outlined, I do think it's well worth taking the time to find a mineral formulation that works for your lifestyle, skin and budget. I'd love to help you out with that, so stay tuned for more product suggestions! In the meantime, let me know what you think:
Do you use natural sunscreen?
Found any good ones I should know about?