This is potentially the most important step of your entire routine so let’s do a deep dive into it.
What Is sunscreen?
This is a product that contain active ingredients which stop UV from getting to our skin.
Why is it important?
UVA and UVB are the ones of concern.You can remember their negative impacts as ‘A’ for ‘aging’ and ‘B’ for ‘burning’.
UV exposure can cause sun damage, premature aging and increase the risk of skin cancer.
Always go for broad-spectrum sunscreens. These protect you from both UVA and UVB rays.
Who needs to wear sunscreen?
Everyone above the age of 6 months should be wearing sunscreen. Having darker skin doesn’t exempt you from wearing sunscreen.
Sun protection factor is a measure of how much longer it takes for UV to burn your skin with sunscreen on versus without sunscreen on.
SPF depends on the amount of sunscreen applied which is why you should apply enough sunscreen.
- SPF 15 blocks 93% UV
- SPF 30 blocks 97% UV
- SPF 50 blocks 98% UV
Higher SPF means more sunscreen active ingredients and it could be greasier and more expensive.
Types of sunscreen
I do not want to oversimplify UV filters and the two types of sunscreen because that is a lot of biochemistry which is complex. Michelle of Lab Muffin Science did a detailed post on this that you can check out. I’ll highlight the main points here:
Chemical (organic) sunscreens
These sunscreens absorb the UV and convert it into less harmful forms of energy, mostly heat.
The active ingredients to look out for include:
- mexoryl SX
- tinosorb M
P.S: Avobenzone in particular is a less stable UV filter and a common irritant or allergen.
The main advantage of chemical sunscreens is that they are less likely to give you a white cast. The downside is that they can be irritating around the eyes.
There is a controversial discussion around the impact of certain chemical filters on coral reefs. Hawaii banned octinoxate and oxybenzone because they may cause coral bleaching.
As I discussed in my eco-friendly post, huge corporations and governments must step up when it comes to saving the planet. Sometimes, putting pressure on individual consumers diverts attention from the bigger environmental issues.
I will keep reading up on this. Some people are going the safe route and avoiding these ingredients, particularly when they go to the beach.
Mineral (physical or inorganic) sunscreen
They absorb UV rays like chemical sunscreens but they also scatter them.
The active ingredients are titanium and zinc oxide.
Pros: better tolerated around the eyes.
Con: They tend to give you a white cast (especially titanium based ones)
When should you apply sunscreen?
Every single day.
Many of us incorporate active ingredients like AHAs and retinoids which make our skin more sensitive to the sun so daily protection is a priority.
How to apply sunscreen
Sunscreen should be applied to your face and body as the last step in your morning skincare routine ( before makeup). Wait 5-10 minutes before applying your makeup so that it can form an even layer.
The rule of thumb is 2 milligrams of sunscreen per square cm which roughly translates to about half a teaspoon for both your face and neck or a shot glass for the entire body.
People use the 2 finger rule for their faces. I like to use two fingers from my finger tip to my palm for my face and neck.
Should you wear sunscreen indoors?
There’s no harm in applying your sunscreen while indoors so I’d say yes. UVA can penetrate through glass and you may spend a lot of time in front of windows.
Does it need to be separate from your makeup and moisturizer?
Yes. This will allow you to apply enough sunscreen for adequate sun protection.
Do I need to reapply sunscreen? If yes, how often?
There is a lot of debate around sunscreen reapplication at the moment.
The UV index is an international standard measurement that tells you the strength of sun-burn producing UV radiation at a particular place and time. This index determines how often we would need to reapply our sunscreen, especially when we are outside and exposed to direct sunlight.
This number varies quite a lot throughout the day but peak times are between 11 am and 4pm.
My two cents on keeping reapplication simple is to follow the directions given on the back of your sunscreen. It often instructs you to reapply:
- every 2-3 hours of sun exposure
- after swimming
- after sweating or any other form of exposure to water.
When I am my most disciplined self outdoors, I will apply sunscreen in the morning and reapply at lunch time but that’s about it.
When I am by the beach or at the pool, I will reapply more religiously.
I wear sunscreen every day even when indoors. Truthfully, I don’t reapply sunscreen while indoors but don’t do as I do.
How do I reapply sunscreen over makeup?
Here’s a video that goes into sunscreen reapplication methods for those of you who wear makeup on a day to day basis.
How to remove sunscreen
I addressed this in my first cleansing post. A gentle foam or gel cleanser with adequate surfactants can remove sunscreen even if it is waterproof.
Cleansing oils and balms are gentle additions to your routine that can be beneficial especially if you wear make-up.
Other sun protective measures
Sunscreen is only one aspect of sun protection. Remember to:
- Avoid prolonged sun exposure.
- Wear sun protective clothing : hats, long sleeved shirts, gloves and shades.
A quick summary
- Wear enough SPF 30/SPF 50 broad spectrum sunscreen as the last step of your skincare routine every day.
- Reapply sunscreen as instructed.
- Do not mix in any other products into your sunscreen because it may interfere with efficacy. This includes oils, moisturizers and makeup.
- Wait 5-10 minutes after application for an even film to form before applying makeup.
- Avoid prolonged sun exposure and wear sun protective clothing.
- Russak JE et al. A comparison of sunburn protection of high-sun protection factor (SPF) sunscreens: SPF 85 sunscreen is significantly more protective than SPF 50 (open access), J Am Acad Dermatol 2010, 62, 348–349. DOI: 10.1016/j.jaad.2009.05.025
- Williams JD et al, SPF 100+ sunscreen is more protective against sunburn than SPF 50+ in actual use: Results of a randomized, double-blind, split-face, natural sunlight exposure clinical trial (open access), J Am Acad Dermatol 2018, 78, 902–910. DOI: 10.1016/j.jaad.2017.12.062