Suncream explained: SPF, PA ratings, and more
In the late spring, summer, and early autumn, Brits have to take care when spending time outdoors. Though sunny weather can be fantastic for our mood, and give us a big boost of vitamin D, it can also be damaging for the skin because of the ultraviolet (UV) radiation.
UVB radiation in sunlight causes redness and burning, while UVA radiation is responsible for skin ageing and pigmentation. Both types can also cause skin cancer – although the majority of skin cancer cases are caused by UVB.
Between late March and early October, when UV radiation is the strongest in the UK, it’s really important to practise sun safety. Even overcast days can be risky, as UV rays can still burn and damage your skin through clouds.
According to the NHS, it’s best to avoid strong, direct sunlight during the hottest part of the day - between 11am and 3pm. During these hours, aim to spend some time in the shade, or cover up with clothing and a wide-brimmed hat.
Understanding SPF, UVA ratings, and PA ratings
There are many different sunscreens available in pharmacies and supermarkets. You might find it hard to know which one to pick, especially if you aren’t sure what all the markings, symbols, and scientific jargon on the label means.
The good news is, the basics of sunscreen are pretty easy to understand once you know what to look for.
Sun protection factor (SPF)
A bottle of sun cream will nearly always have the letters “SPF” on the front – this stands for sun protection factor. SPF indicates the level of protection against UVB radiation – the type that leads to burning and increases your risk of skin cancer. The higher the number, the better the level of protection.
The NHS recommends always using a sun cream with an SPF of at least 30.
In the UK, the level of protection against UVA rays will usually be represented with a star rating out of five. As with SPF, the higher the rating, the better the level of protection.
Alternatively, some sun lotions available in the UK may represent their UVA rating with the letters “UVA” in a circle. This is a European marking indicating that the UVA rating meets European standards.
The NHS recommends always using a sun cream with at least a four-star UVA rating, or the European approval mark.
The term “broad spectrum” sometimes appears on sun cream labels that offer both UVA and UVB protection. Looking for this term can be a handy way to find a sunscreen that offers adequate protection – although it’s still a good idea to double check the SPF and UVA rating before you buy.
The PA rating is sometimes seen on international sunscreens – especially those from Japan. It’s another way of rating the UVA protection offered by a sunscreen.
Rather than scoring out of five stars, the PA system gives one of four ratings: PA+, PA++, PA+++ or PA++++. As expected, a sunscreen rated with PA++++ offers the most UVA protection.
There’s disagreement about how reliable this system is, which is why it isn’t used on sunscreens made in the UK or Europe. However, you might see it used on sunscreens that you buy overseas.
Understanding ingredients and formulas
There are two main types of sunscreen, chemical and mineral. Chemical sunscreens tend to be more widely available.
This type of sunscreen works by absorbing UV light and releasing it as heat. The ingredients commonly used in chemical sunscreens are oxybenzone, avobenzone, octisalate, octocrylene, homosalate, and octinoxate.
Chemical sun creams are thinner in texture than mineral sun creams, and are designed to be absorbed into the skin. They don’t work immediately and need to be applied before you plan to go out in the sun. Chemical sunscreens also need to be reapplied regularly.
This type of sunscreen sits on the skin and creates a physical block, helping to deflect UV rays. The main ingredients in mineral sunscreens are titanium dioxide and zinc oxide.
Unlike chemical sunscreens, mineral sunscreens can provide immediate protection after application, and tend to last longer. They also tend to be less irritating on sensitive skin.
A downside to this type of sun cream is that they can leave a white cast on the skin.
Reapplying sun cream (even when you’re indoors)
Reapplication of sun cream is really important – no matter what type you’re using.
Chemical sunscreens need to be reapplied regularly as they absorb into the skin quickly. Mineral sunscreens can last longer but they should also be reapplied as they will rub off over the course of the day.
The NHS advises that if you’re going to be out long enough to burn you should apply your sun lotion twice: 30 minutes before you leave, and then once again just before you go out the door.
Once you’re outside, it’s a good idea to reapply every two hours, or if your sun cream gets rubbed or washed off. Other than that, follow the instructions on the bottle.
As for the question of wearing sunscreen indoors? The British Skin Foundation advises that UVA rays can travel through glass, so if you’re going to be inside spending time next to a window, it can be a good idea to wear sunscreen – and to reapply it throughout the day. The same goes if you’re taking a long car journey.
How to look for a quality sun cream
Whether or not you’re preparing for a beach holiday, it’s important to make sure that you’ve got plenty of sun lotion stocked up for the spring, summer, and early autumn.
When looking for your perfect product, remember the NHS guidance:
- SPF of at least 30
- UVA rating of at least four stars
Beyond that, it’s a case of personal preference!
If you have sensitive skin, you’ll probably benefit from using a mineral sunscreen – so look for titanium dioxide or zinc oxide on the label. If you’re buying sunscreen for your kids you might want to opt for a higher SPF, and buy a product that shows up clearly on their skin so you don’t miss any spots.
Our last piece of advice? Buy more sun cream than you think you need! The NHS recommends that an adult needs two whole tablespoons to cover their entire body when wearing a swimming costume, and two whole teaspoons to cover just the face, head, neck, and arms.