SPF, sun cream, sunscreen, sunblock… Whatever you call it, sun protection is hailed as the Holy Grail to keeping skin youthful. But, whilst wearing sunscreen is an age-old tip, even the most skincare savvy don’t necessarily know exactly what SPF is, what it stands for and what its benefits are. But, before we dive into why sunscreen is important, let’s look at the different types of UV radiation...
SPF: What, When, Where?
What’s the difference between UVA and UVB rays?
The sun emits several types of UV radiation, and two of these are harmful to our skin: UVA and UVB rays.
UVA is a long-wave light and can penetrate the skin pretty deeply, reaching the upper layers of the dermis (the second layer of skin). Whilst the harm that UVA rays cause might not be immediately visible, over time, they’re responsible for premature wrinkles and other signs of ageing (like pigmentation and loss of elasticity), even contributing to skin cancer.
UVB, on the other hand, is a short-wave light, so these rays mainly affect the epidermis (the outer layer of skin). They’re mostly responsible for surface skin damage like sunburn and these, too, can lead to certain types of skin cancer.
To keep it simple, think ‘A’ for ageing and ‘B’ for burning. So, where does SPF come in?
What is SPF?
These 3 letters are thrown about in the skincare world all the time, but what do they mean?
SPF stands for sun protection factor and indicates the amount of protection a sunscreen will provide against the sun’s harmful UVB rays (note: not UVA rays). So, wearing an SPF means you can stay out in the sun for longer with a lowered risk of getting sunburnt.
How does SPF work?
So, let’s look at how this magical product works - it all comes down to how long it protects the skin from the sun’s radiation by filtering out UVB rays.
By multiplying the number of minutes it normally takes you to burn without wearing sunscreen by the sun protection factor, you’ll get the amount of time your skin will be protected from the sun. Let’s look at an example...
If, say, you can typically be in the sun for 10 minutes before getting burnt (without sunscreen), wearing an SPF15 sunscreen will give you 15x10 minutes of sun protection. So, after a quick bit of maths, this means you’ll be protected for 150 minutes, or 2.5 hours.
How SPF works also depends on its type: whether it’s physical or chemical. Physical sunscreens (a.k.a. mineral sunscreens) keep the skin safe by creating a protective barrier on the skin that deflects sun rays. Chemical sunscreens, alternatively, are filled with ingredients that absorb UV rays.
What SPF should I use?
Okay, so you’ve probably guessed that the higher the SPF, the longer it will keep your skin safe in the sun (and the higher the percentage of UVB light it blocks). The level of protection SPFs provide range from low (roughly SPFs 4-10) to very high (SPFs 50+). Both the British Association of Dermatologists and the American Academy of Dermatology recommend using a sunscreen that has at least SPF30.
So, if SPF is all to do with protection from UVB rays, how can we protect ourselves against UVA rays? Let’s have a look.
What is a broad spectrum sunscreen?
To make sure you’re shielding your skin from both UVA and UVB rays, you need a sunscreen that’s labelled broad spectrum - this type of sunscreen offers both types of UV protection in one.
Using a broad spectrum sunscreen will help fend off both UVA and UVB rays. In the UK, you can check how well a broad spectrum sunscreen will defend against UVA rays by looking at its star rating, which ranges from 0-5 (with 5 indicating maximum protection). This star rating refers to the amount of sun protection a sunscreen provides in proportion to its UVB protection. It’s important that your sunscreen has a high SPF and a high star rating to make sure you’re getting the best protection - a minimum of 4 stars is often recommended.
When should I apply sunscreen?
Ideally, sunscreen should be worn every day for maximum skin protection - and this means on cloudy days too! This might sound silly, but UVA rays can reach us even through clouds and glass, so it’s best to have SPF at hand at all times.
And when it comes to how often you should apply your sunscreen, skincare experts typically recommend reapplying your sunscreen every two hours and if you’ve been swimming, you’ll need to reapply your SPF right away.
Where should I apply sunscreen?
It seems pointless to say it, really, but you should apply your sunscreen to all parts of the skin that could be exposed to the sun - face, arms, chest, legs… Anywhere that’s at risk of coming into contact with the sun.
What are the benefits of SPF?
Okay, so by now it’s probably pretty obvious why SPF is important, but I’ll sum everything up here anyway.
Using a broad spectrum sunscreen is vital if you want to keep lines, wrinkles and age spots away (that’s everyone, right?). UV rays can break down collagen and elastin, both of which keep our skin looking youthful, so it’s important to stop UV rays reaching our skin as much as possible. According to Mayo Clinic, exposure to damaging UV rays is the main cause of premature wrinkles - so you’ll definitely want to whip out the SPF! And one of the biggest SPF benefits is that it helps prevent sunburn and lowers the risk of developing skin cancer - so it’s a pretty great product for skin health. But, of course, keeping out of direct sunlight as much as possible and wearing protective clothing is also super important.
We’re probably all guilty of skipping SPF on some (most) days - I know I definitely am! But, now you know why sunscreen is a must. Making sunscreen an everyday skincare essential is one of the best ways you can avoid premature ageing and keep your skin happy and healthy. Looking for other ways to keep your skin healthy? Check out this list of vitamins for glowing skin.