Let’s talk about protecting our skin from the sun. It’s a big job. A lot of people think, “well I don’t spend a lot of time in the sun.” But that’s just not true. The truth is you don’t have to be at the beach or sunbathing or even outside to be “spending time in the sun.” UVA rays can penetrate the windows of your home or car and are doing damage to your skin every day if you’re not wearing a good sunscreen.
Some people believe that if you don’t get a sunburn that means you aren’t getting sun damage. A sunburn means you’ve had an overexposure to UVB rays. But we are exposed daily to the sun’s UVA rays as well. In fact, 95% of solar radiation is UVA. Even on cloudy days, these rays get through enough to do damage. Just because you can’t see the sun doesn’t mean you don’t need protection.
Both UVB and UVA rays have been linked to skin cancer. And UVA rays are responsible for the majority of the extrinsic aging of the skin. Extrinsic aging is the aging or decline of the skin caused by external factors like sun damage, smoking, diet, etc. If you could prevent or at least slow this decline, wouldn’t you? Or if wearing a sunscreen every day could prevent skin cancer? Well, that seems like a no-brainer to me.
The Lie of SPF
SPF (Sun Protection Factor) is a measure of UVB protection. It doesn’t measure the level of protection from UVA rays. It’s technically a measure of redness. Moreover, it’s how long you can stay in the sun before getting burned. An SPF 15 means you can stay in the sun fifteen times longer while wearing the sunscreen than you could without it. An SPF 20 means you can stay in the sun twenty times longer. After SPF 30 it stops increasing linearly. So, SPF 100 will not allow you to stay in the sun 100 times longer, for example. Dermatologists recommend wearing a minimum of SPF 30.
In the US, there is not a quantitative UVA rating system like there is for UVB rays. Also, there are newer UVA filters available in many other countries that would greatly increase the UVA protection of American made sunscreens that the FDA has yet to approve. There has been much controversy and debate over UVA testing methods.
So, many sunscreens in the US will protect you from getting burned but not dependably from getting sun damage that will cause irreversible aging and potentially skin cancer.
There are some countries that do have quantitative UVA rating systems. Japan uses the PA+++ scale, Australia uses the PPD (Persistent Pigment Darkening) scale, and the UK uses the Boots 5-star rating system. I will explain how to understand these systems in a future post.
What can you do?
Here’s where you must be a savvy consumer if you want to really protect your skin: as of right now the U.S. FDA hasn’t approved more than two substantial UVA filters for use in sunscreens. (There are a couple more but they provide very limited protection in the UVA spectrum.) When you shop for sunscreen you want to look for these two specific UVA-blocking ingredients: Zinc Oxide and/or Avobenzone.
All sunscreens have to list their “active ingredients” separate from their inert ingredients, so it only takes a couple seconds to locate and discover what a sunscreen’s active ingredients are. Most sunscreens offer reliable UVB protection so you can just focus on finding these UVA ingredients.
Avobenzone is very photo-unstable, which means it degrades rather quickly in any type of light. It is easily stabilized in sunscreen formulations, however, by the addition of octocrylene. So, if your sunscreen relies on avobenzone for UVA protection, make sure there is also octocrylene in there. Neutrogena’s patented “Helioplex” contains a special ingredient called DEHN that stabilizes avobenzone. Or you may see an ingredient called Solastay (Ethylhexyl Methoxycrylene)—this is also an avobenzone stabilizer.
Zinc Oxide is commonly used at around 2-7% concentrations but you should look for 5% at a minimum with 10-20% being ideal. (25% is the legal maximum. At very high concentrations zinc-based sunscreens can make the skin appear white unless you get one with nano-zinc oxide, which I will explain in a future post.) Avobenzone is always used at 3%. If it says anything other than 3% you’ll want to avoid it.
Sunscreens that use zinc oxide alone as an active ingredient or zinc oxide and titanium dioxide are physical sunscreens. They are usually better tolerated by those with sensitive skin and their mechanism of action is to deflect and scatter rays. Any other sunscreen ingredient you might see is going to fall under the chemical sunscreen category. These sunscreens work by absorbing the rays (note how important it is that you have an ample amount on your face so that the sunscreen is absorbing the rays and not your skin.) Often sunscreens will be a mix of both chemical and physical active ingredients.
Shame on the FDA
Many sunscreens will say “broad spectrum” on them but this claim doesn’t mean much in the US at the moment. It is important that you check the ingredients.
British researchers looked at US sunscreens meeting the standard for FDA “broad spectrum” protection and estimated that “over a two-week vacation to a tropical latitude, a fair-skinned tourist could successfully prevent sunburn but receive as much UVA exposure as he or she would by visiting a tanning salon 10 times–for eight-minute sessions.”
These are the same sunscreens that can claim they help reduce the risk of skin cancer! This is what you’re getting when you simply grab any sunscreen with the words “broad-spectrum” on it in the US right now! This is why it’s SO important to know what UVA protective ingredients to look for. It sometimes takes a little hunting around, but your skin and your health are ultimately worth it. The Environmental Working Group’s website has several recommendations for truly broad-spectrum sunscreens. https://www.ewg.org/sunscreen/
I sincerely hope that the United States FDA will approve these newer UVA filters ASAP. In the meantime, we can make the most informed consumer decisions possible, wear sunglasses, hats and protective clothing, as well as seek shade whenever possible. And if you happen to be visiting Japan, Australia or the UK anytime soon I recommend picking up some sunscreen while you’re there! (Look for a high UVA rating in addition to the SPF. You will see ingredients you won’t see in the U.S.)
 Brian L Diffey et al., Suntanning with Sunscreens: A Comparison with Sunbed Tanning. Photodermatology, Photoimmunology & Photomedicine, 2015, 31(6), 307–314.