To understand what to look for in a sunscreen, we must first understand UV radiation and its different forms. This is because just about every sunscreen sold has some slightly different combination of active ingredients that act as filters. Each of these filters shields our skin from different forms of UV radiation at varying degrees of efficiency. What’s a consumer to do? Educate themselves.
UV stands for ultraviolet and is a form of light energy. It’s part of the solar spectrum and is harmful to us. It’s a proven carcinogen.
Sunlight is composed of the following: visible light, infrared light, and ultraviolet light (UV). The UV part is what we should be concerned with. If skin cancer isn’t enough to get you to wear sunscreen faithfully, the ugly things it can do to your skin should hopefully help.
Bear with me while I get a little sciencey and break down the three types of UV radiation. This will hopefully help inform your sunscreen choices down the road:
UV is measured in terms of wavelength or nanometers (nm).
There are 3 types of UV radiation, and each one covers a different range of the light spectrum.
UVA (320-400 nm)
UVB (280-320 nm)
UVC (100-280 nm)
We only need to be concerned with UVA & UVB. Luckily, the ozone layer blocks UVC from ever reaching us.
The “Aging Ray” (An easy way to remember this is to remember the A stand for “aging.”) This part of the spectrum causes the most long-term damage to our skin.
UVA rays are the longest of the rays. They are therefore able to penetrate deeper into the skin. They penetrate all the way into the dermis (the layer of skin below the epidermis) and into the hypodermis (the layer of subcutaneous fat).
When you consider that your dermis is 70% collagen and contains most of the collagen and elastin in your skin, this is a pretty big deal. The collagen and elastin found within the dermis create a ‘scaffolding’ that supports your skin and gives it structure.
When UVA rays reach the collagen and elastin fibers found within your dermis, they become dysfunctional and lose their shape, causing the ‘scaffolding’ to collapse over time. This is a huge reason skin wrinkles and sags. (Tan for a week = wrinkled and sagging for years to come!)
What most people fail to recognize is that UVA is present all the time, every day, rain or shine. Even on a very cloudy day, UV rays are doing damage to your skin. In fact, 80% of it passes right through clouds!
It’s a mistake to assume you only need sunscreen when you’re at the beach or planning to be in direct sunshine for a prolonged period of time. The sun doesn’t have to be visible for UVA rays to be present. So long as it’s daytime, they are lurking.
UVA is insidious—the damage it inflicts cannot be seen immediately. The cumulative effects show up later as thickened, wrinkled, lax, spotted, skin.
UVA penetrates right through window glass. Even if you don’t spend much time outside, it’s imperative to wear sunscreen daily—whether you’re leaving the house or not.
The “Burning Ray” (remember “B” for burning), UVB is the culprit anytime your skin burns.
UVB rays are shorter than UVA, and so they travel a shorter distance into the skin. They mostly inflict damage on the epidermis (the outermost layer of your skin), and can gradually do a smaller amount of damage to the dermis as well.
The radiation intensity of UVB is 1,000 times stronger than UVA’s intensity. UVB is more cytotoxic and mutagenic than UVA radiation, which means it can actually modify your cell’s DNA. Therefore, UVB is the major cause of skin cancer.
Unlike UVA, UVB does not penetrate glass.
Maybe you believe that you don’t need to worry about sun protection when you’re in a car or in the house. It’s true that you usually can’t really get a sunburn through glass. You can, however, get a significant amount of damage from UVA rays that will lead to premature aging or even cancer when you’re in a car or anywhere indoors that has windows.
As I mentioned previously, UVC radiation is absorbed by the ozone layer and doesn’t reach the ground. The ozone layer thankfully still protects us from UVC radiation. UVC radiation would literally kill us by cooking us to death!
UVA in Review
- UVA is what is primarily responsible for aging, inflicting major damage on collagen & elastin
- 95% of the sun’s radiation is UVA
- UVA goes right through clouds and window glass
UVA is always present during daylight. One of the main causes of skin aging is sun damage (mostly from UVA rays) and we can do something to prevent it. That something is proper sunscreen, sunglasses, protective clothing as well as sun avoidance during peak hours.
UVB in Review
- UVB primarily causes burning
- UVB is a major cause of skin cancer
- UVB is stronger during the summer and closer to the equator
UVA and UVB cause:
- skin cancer
- skin aging
- pigmentation (sun spots and melasma)
As soon as you get out of bed in the morning, you should put on that sunscreen! With such alarming consequences for failing to protect our skin, how do we know which sunscreen is best suited for the job?
Recall from this post, SPF is not a measure of protection per se. Rather, it indicates how long it will take for UVB rays to redden skin, as compared to how long skin would take to redden without the product.
For instance, someone using a sunscreen with an SPF of 15 will take 15 times longer to redden than without the sunscreen. An SPF 15 sunscreen screens 93 percent of the sun’s UVB rays; SPF 30 screens about 97 percent; and SPF 50, 98 percent.
“The most misunderstood part of sunscreen is UVA.” Explains Dr. Kundu, a board-certified dermatologist from Northwestern Medical Group in Chicago. “UVA is around every day; it can penetrate through window glass. Like UVB, it’s also related to an increased risk of skin cancer, but unlike UVB, it’s not filtered by the ozone at all. UVA doesn’t cause sunburn, but it really leads to skin darkening and aging, because it penetrates deeper into the skin and has more influence in the collagen.” Dr. Kundu warns.
Sunscreens typically contain several active ingredients (2-5 on average). These actives work in synergy to provide broader coverage than one ingredient can do alone, as well as add stability to the formula.
Don’t worry about learning all of them. Just pay attention to four key UVA ingredients. Most sunscreen formulas offer reliable UVB protection, so your focus should be on the UVA ingredients.
Which UVA Active Ingredients Are Most Effective? (*note-these are the most effective UVA actives available in the U.S. at the time of this writing)
There are four ingredients that will provide protection in the UVA spectrum (but not all equally)
1. Zinc Oxide
2. Titanium Dioxide
4. Ecamsule (often listed by its trade name, Mexoryl SX, patented by L’Oréal)
Your sunscreen must contain at least one of these four ingredients. So, which do you choose?
First, decide whether you want a physical or chemical sunscreen. If your skin is sensitive at all, you may do better with a physical sunscreen. You may want to try both to see which you like better.
If You Think You’d Like a Physical Sunscreen:
When looking at Zinc Oxide or Titanium Dioxide, Zinc Oxide is definitely the better choice. Many physical-only sunscreens are a combination of both filters.
- Zinc Oxide provides the most complete protection in the entire UVA spectrum (280-400 nm). It protects against both UVA-1 and UVA-2 rays.
- While Titanium Dioxide provides good coverage for UVA-2 (320-340 nm), it is weaker and provides insufficient protection for UVA-1 (340-400 nm).
- Zinc Oxide by itself in a formula isn’t sufficient if a high SPF is required (like you need high UVB protection because you’ll be in intense sunshine or you burn easily). For this reason, Zinc Oxide is often combined with UVB filters, such as Octocrylene. But if you don’t expect to be under intense sun for a long period, a Zinc sunscreen without an additional UVB filter is fine.
- You’ll want a minimum of 5% Zinc Oxide in the formula but ideally 10-20%
Physical sunscreens technically do not need to be reapplied every two hours, unless you are sweating, swimming, or they somehow get wiped off. They form a physical barrier over the skin. It’s not a bad idea to do anyway if you’re able to since your skin produces oils that may disrupt the original barrier formed. But since reapplication every two hours isn’t always realistic, it’s a good thing to know and often a reason to choose a physical sunscreen over a purely chemical one.
If you don’t like the feel or look of some of the Zinc based sunscreens you try, I suggest looking into nano-based Zinc formulas. I will go into this more in another post, but essentially there are newer Zinc based products made with nano-sized particles of Zinc that do away with the white look many of them impart. Alternatively, there are several tinted Zinc-based sunscreens (usually the tint is too dark for the pale set, however).
If You Choose to Try a Chemical Sunscreen:
- Avobenzone is a great UVA filter but it’s very photo-unstable, meaning it gets degraded by light quickly. This is addressed by adding photo stabilizers such as Octocrylene or encapsulating the ingredient into liposomes.
- Neutrogena’s patented Helioplex contains Avobenzone, Oxybenzone, and DEHN (diethylhexyl 2,6-naphthalatate). DEHN is an ingredient that stabilizes Avobenzone.
- Solastay (Ethylhexyl Methoxycrylene) is a photostabilizer for Avobenzone and Octinoxate.
- Ecamsule (Mexoryl SX) is limited to L’Oréal owned brands (e.g. La Roche Posay’s Anthelios SX line, Lancôme), since L’Oréal has the patent on this ingredient.
- La Roche Posay’s Anthelios SX contains Ecamsule, Avobenzone, and Octocrylene (to stabilize the Avobenzone).
Chemical sunscreens must be reapplied every two hours. They lose their ability to absorb UV rays after that time.
There are several decent sunscreens that contain a combination of both physical and chemical sunscreens. In fact, it’s my preference. It’s all about becoming a student of ingredients lists. It seems overwhelming at first, but it becomes second nature. Remember, the presence of the ingredient isn’t enough—-the percent is of vital import. Refer back here for this info. You can also check the quite helpful EWG.org’s yearly guide to sunscreen, where they compile a list of the very best each year.
If you recall this post, my favorite sunscreens are Japanese. I don’t spend more than around twelve dollars on a one to two-ounce bottle and am able to easily order them online. Hopefully, that doesn’t change before the FDA makes changes to the filters they will allow sunscreen manufacturers to use in the US. For information on where I get my sunscreen/what I use, send me an email at email@example.com.
The filters I’ve listed in this post will suffice when it comes to UVA protection, but if you want to get serious about protecting your skin from UVA rays (say you struggle with melasma, or are just crazy about your skincare/anti-aging) you’ll want to look into European or Asian sunscreens with high “PPD or PA” ratings. In Europe for example, you have options for UVA protection such as Mexoryl XL (patented by L’Oréal, the oil-soluble version of Mexoryl SX), Tinosorb S, and Tinosorb M.
With sunscreen offerings in the US being a bit subpar, we fortunately still have some other options to help us safeguard our skin. Protective clothing, sunglasses, avoidance during peak hours, and perhaps my favorite—the sun hat! If you don’t already have a large brimmed hat that you love (I know, for some women, this probably sounds like an oxymoron) you should get one! Avoid holes or gaps in the weave, and preferably get one with a UPF (ultraviolet protection factor) rating.
This is a great way to keep the sun off your face–picking up the slack for any shortcomings in your sunscreen. Perhaps this isn’t a look you see yourself in, but don’t dismiss it totally just yet. It kind of grows on you. (And it’s a far better look than sunspots or wrinkles, I promise you!) Here is some more hat-spiration for you…
All these ladies are missing now is their sunglasses. I wear my hat and sunglasses when driving and when I’ll be outdoors for an extended period of time. Don’t forget your hands and lips!
I’d love to hear from you. What’s your sun strategy? Scroll down the page a bit to comment!