Sunscreen
While maybe not the most exciting step in your routine, sunscreen is definitely the most important! Other steps in my routine get ignored here and there but I never leave the house in the daytime without an SPF. Sunscreen protects you from the sun's harmful UV rays that cause sunburns, hyperpigmentation, premature aging, and skin cancer. All the steps that are used in your routine before sunscreen are maintaining and correcting the damage that's already been done to your skin. So why wouldn't sunscreen, a step that prevents further damage, be more important?
First, The sunscreen Lingo
UVA, UVB, SPF, Broad spectrum & PA++++ - these are are the things you might find on the label of your sunscreen, but what do they mean?
UVA: the longest ultraviolet rays coming from the sun that penetrate deep into the dermis level of our skin. Commonly known as the UV Aging ray because it attacks the collagen (proteins that give the skin its structure) in the dermis and causes you to age prematurely.
UVB: the shorter ultraviolet rays from the sun that only penetrates the skin superficially, causing sunburns and the majority of skin cancers. This is why they're also known as the UV Burning rays.
SPF: stands for sun-protectant factor and is a measure of how many times longer a sunscreen will protect you from UVB rays than just your skin can. For example, if you usually burn after 10 minutes in the unprotected sunlight, but the sunscreen you're wearing is SPF 45, then that sunscreen will protect you from burning for (10mins x 45spf ) 7.5 hours!
PA+++: in the same way SPF measures protection from UVB rays, PA measures protection from UVA rays. The more plus symbols, the better so a sunscreen labeled PA+ provides low UVA protection while PA+++ provides high protection.
Broad Spectrum: means the sunscreen protects you from both UVB and UVA rays.
Physical vs. Chemical Sunscreen
Sunscreens are often categorized as either physical or chemical. Physical sunscreens are known as the classic thick, white formulas like the kind your parents used to lather you with as a kid that left you looking ghostly, while chemical sunscreens are known as the light, undetectable formulas like the Glossier invisible shield that truly is invisible when applied. The category “physical” likely came from the thought that zinc oxide and titanium dioxide create a barrier between your skin and the sun and physically block the UV rays while all the other UV protecting “chemicals” absorb the UV and convert it to a heat wavelength that isn’t harmful to the skin. This categorizing into “physical” and “chemical” sunscreens aren’t black and white because both of their ingredients are chemicals (anything you can touch is a chemical!) and both work mostly the same way when it comes to protecting you from the sun. However, these categories are what’s been historically used by the market so I’ll let them live!
Physical sunscreen filters: Zinc Oxide & Titanium Dioxide
Chemical sunscreen filters: everything else - Avobenzone, Octocrylene, Octinoxate, Octisalate, Oxybenzone, Homosalate, Mexoryl SX, Mexoryl XL, Tinosorb S, Tinosorb M
The physical sunscreen filters are white in color and often leave a white cast behind on your skin depending on how they’re formulated. They’re better for those with sensitive skin but are typically thicker, greasier formulas than the chemical ones.
Chemical filters are light-weight and more cosmetically elegant due to leaving no white cast on the skin. They protect better against UVA than physical filters but aren’t as photostable and can occasionally cause reactions.
How sunscreen works
Sunscreens undergo a chemical process to protect your skin - they absorb UV rays, convert them to heat, and then release the heat from the skin. Once applied, sunscreen starts protecting you immediately. Any rumors you’ve heard about wait times are only valid as far as allowing for the sunscreen to dry in an even layer.
All sunscreen ratings are measured for 2mg per square centimeter on the skin (for the average face this is about 1/4 tsp of sunscreen). So if you’re applying less than this, you’re not getting full protection! This goes for foundations too, which is why it’s important to wear an SPF under your foundation since its really unlikely you’re applying 1/4 tsp of foundation at a time.
Contrary to some info out there, sunscreen is designed to sit on top of the skin rather than penetrate it. Formulators minimize the amount that penetrates by making the filter molecules larger and including other ingredients that inhibit penetration. Because sunscreen sits on top of the skin, it’s prone to wearing off throughout the day and so it should be reapplied depending on your activities and time spent outside.
What Type of Sunscreen is Best?
The best type of sunscreen is the one that you’re going to wear! Both physical and chemical sunscreen filters have their pros and cons so it all comes down to what feels better on your skin. If you wear a full face of makeup to work 5 days a week that doesn’t sit well on top of those thicker physical formulas, then a sunscreen with a chemical filter base would suit you. But if you have sensitive skin that can’t tolerate the irritation that some chemical filters can cause then a sunscreen with zinc oxide or titanium dioxide would suit you better.
Physical sunscreen recommendations: La Roche-Posay Anthelios 50 Mineral Ultra Light Sunscreen Fluid, Etude House Sunprise Mild Airy Finish SPF 50 PA+++, Drunk Elephant Umbra Sheer Physical Daily Defense Broad Spectrum Sunscreen SPF 30, Farmacy Green Screen SPF 30, Supergoop Smooth & Poreless 100% Mineral Matte Sunscreen SPF 40
Chemical sunscreen recommendations: Bioré UV Aqua Rich Watery Essence SPF 50+ PA ++++, Shiseido Senka Aging Care UV Sunscreen SPF50+ PA++++, Glossier Invisible Shield SPF 35
Hybrid sunscreen recommendations: Innisfree Perfect UV Protection Cream SPF 50 PA+++, COSRX Aloe Soothing Sun Cream SPF 50 PA+++, Heimish Artless Glow Base SPF 50 PA+++, Tatcha Silken SPF 35 PA+++, EltaMD UV Clear Broad-Spectrum SPF 46