Summer has officially arrived and with that comes trips to the beach, the park, the trail and countless other outdoor activities. It also comes with more exposure to sunshine. Given that sun exposure is linked to the vast majority of premature aging and most skin cancer, it’s wise to take precaution. Wearing protective clothing and avoiding direct sunlight between the hours of 10 and 2 are the best way to avoid getting too much sun, but when that’s not possible, a good sunscreen is your best bet. Store shelves are stocked full of sunscreen options this time of year, but before you just grab any ol’ bottle, it’s best to understand what kind of protection you’re getting.
First, let’s take a quick look at what’s going on with those sunshine rays. Sunlight shines down in several forms of radiation, but for the sake of this post we’ll only concern ourselves with UV-A and UV-B rays. These two types of ultraviolet light are the ones that most affect your skin.
UV-A rays have longer wavelengths and penetrate deeper into the lower dermis layer of the skin. These rays are responsible for damaging collagen, elastin and DNA and are the biggest culprit to aging of the skin. UV-A radiation can penetrate glass, and is fairly consistent in intensity through out the year and during the day. (So sunscreen up year round.)
UV-B rays are shorter and cannot penetrate as deeply into the skin. These rays are stronger however, and are what cause your skin to burn. They are also the main cause of skin cancers. UV-B radiation is higher during summer months and also during mid-day, but has the potential to burn and cause damage year round.
The active ingredients in sunscreens fall into two categories: mineral/physical sunscreens or “chemical”/organic sunscreens (organic here simply meaning that the compound contains carbon atoms). Most sunscreens use one or the other, though sometimes they combine both. These two types of ingredients work and perform very differently, so you may want to start looking at your ingredient labels. To decide which is best for you, let’s look at how they work.
First up, my personal favorite, the physical sunscreen ingredients. These ones are easy to recognize since there are only two, zinc oxide and titanium dioxide. These are inorganic compounds (no carbon) that physically block UV rays, much like tiny mirrors, by reflecting them away from your skin.
Zinc oxide is best, as it protects against the full range of UV-A and UV-B rays. Titanium dioxide does not protect from UV-A1. A combination of both is often seen in the ingredients. The physical sunscreens are very stable, as they do not degrade when exposed to UV rays. They are also effective immediately after applying. The only downsides to these guys are that they do rub off more quickly, and are solid white. Those with darker skin tones often appear a bit pasty with these guys.
The chemical or organic sunscreens work entirely differently than their physical counter parts. Rather than reflecting UV rays, chemical sunscreen molecules absorb the UV radiation and dissipate the energy as lower, less harmful energy rays. So, where physical sunscreens are mirrors, chemical sunscreens are more like sponges. You have to wait about 20 minutes after application for the ingredients to become active. One of the pluses is that these ingredients leave no white residue and are easier to spread across skin.
There are all kinds of complex sounding chemical sunscreens, though the most common are oxybenzone, octinoxate, homosalate and avobenzone. No single chemical sunscreen ingredient offers broad spectrum protection against UV-A and UV-B so they are often used in combination. Also, none other than avobenzone offer protection from UV-A1. However, avobenzone is notoriously unstable, meaning it degrades quickly after being exposed to UV rays. Because of that, additional stabilizers have to be added to keep it from degrading so quickly. Sound complicated? Yeah, it is. That’s why I prefer physical sunscreens.
The biggest reason I do not recommend chemical sunscreen is that, while the UV energy is dissipated, it is still held against your skin to a degree. Those with hyperpigmentation will often find the problem worsens from these types of sunscreens. The dissipated UV energy may not be strong enough to cause much damage, it does still however excite already overactive melanocytes. If you have melasma or another form of hyperpigmentation, definitely go with a physical sunscreen.
Regardless of which type you choose always make sure it says “broad spectrum protection” or “UV-A/UV-B protection”. SPF only refers to protection from UV-B rays, and as we just learned, that doesn’t entirely help. Then flip the bottle over and find the active ingredients so you know how that sunscreen is working with your skin.