As we shared in our previous article about the importance of sunscreen - the goal of our armour is to protect us from sun damage caused by all components of sunlight.
Let's recap - so UVB rays cause your skin to burn and UVA rays and HEV light causes your skin to age. How do we know how well a sunscreen is able to protect us from these components of sunlight?
Starting off we a familiar old friend - the SPF rating.
Rightfully mentioned by the MD Anderson Cancer Centre, a sunscreen’s SPF is merely a measure of how well it protects you UVB rays. A higher SPF number doesn’t necessarily mean better protection from sun damage as a whole! An SPF 15 sunscreen blocks 93% of UVB radiation, and SPF 30 blocks 97%. After that, the difference in protection is small. SPF 50 blocks 98%, and SPF 100 stops 99% of UVB rays from reaching your skin.
As most medical professionals will agree, a minimal rating of SPF 30 is required for adequate UVB protection, only if reapplied every 2 hours. Across the board, most of us are more comfortable having a SPF 50 rating but that does not mean slacking off on reapplication. It is CRUCIAL to note that the SPF rating only works with adequate amount of product so don't forget to use your sunscreen sufficiently.
However, this has no bearing on the product's protection against UVA rays and HEV light!
The worst part of all, is that UVA rays make up close to 95% of UV radiation in sunlight. How can we estimate the amount of protection the product accords us against UVA?
Unlike SPF ratings which are universal, UVA ratings differ from region to region.
- UVA in a circle symbol: used in Europe, means that UVA protection is at least 1/3 of the SPF.
- PPD (Persistent Pigment Darkening), mainly used by some French drugstore brands: equivalent to SPF, it tells you the exact number of UVA protection.
- The PA (+ to ++++): used in Japan and Korea, means Protection of UVA, and is based on the PPD.
- PA+ is PPD 2 – 4
- PA++ is PPD 4 – 8
- PA+++ is PPD 8 – 16
- PA++++ = PPD > 16.
So depending on the brand of product you purchase, the ratings may be expressed differently so do take note!!
Last but not least - protection against HEV light.
This is where things get tricky. Take a walk down the cosmetic aisle at any department store and almost every sunscreen product claims to be "blue light" protective. But this is not always necessarily true.
Like UVA rays, HEV light generates free radicals and cause skin cells to produce enzymes that break down the collagen and elastin that gives your skin its plump, youthful appearance.
Based on current literature, the two common strategies to protect your skin from visible light are - iron oxides and the presence of antioxidants. Let's break it down together.
Iron oxides are common ingredients in tinted sunscreens and enhance protection against HEV light, especially when combined with zinc oxide as shown in a 2021 study in the Journal of Cosmetic Dermatology by reflecting HEV light away from the skin, mitigating photoaging effects. However, the presence of Iron Oxides can give a tinted appearance which may not be suitable for skin types!
Another strategy is to include antioxidants in the product to minimize the oxidative stress caused by free radicals generated. Some common ingredients used include ferulic and caffeic acids, green tea and vitamins C and E.
But what makes a sunscreen a better bang for your buck? Not only preventing sun damage, but correcting existing sun damage such as hyperpigmentation from prolonged sun exposure. That’s why our bare screen. transparent gel sunscreen remains our favorite sunscreen! The addition of alpha arbutin helps to lighten areas of hyperpigmentation throughout the day while still protecting you from further damage! We worked so hard to give you the most all rounded sunscreen regardless of skin type or texture - so you can enjoy your time in the sun, stress free!
TLDR: an ideal sunscreen should have adequate protection against UVA, UVB and HEV light rays. A few common things to look out for: SPF 50, PA ++++, HEV light protection with iron oxides or antioxidants.