SPF Terms Made Simple

how to decode your spf

Do you find SPF terms confusing? If yes – I’m not surprised! There are lists of countless ingredients that we’ve all probably only come across in our chemistry exam. Along with mysterious abbreviations, star ratings and measurements. And, if that wasn’t enough, what do you prefer to use, chemical or mineral SPF? What does it all mean?

Well, I’m here to help you decode SPF and all of its variations. In this edit, I’ll be tackling some of the key questions you’ve been searching on Google…


#1 What is SPF and why do I need it?

SPF stands for sun protection factor, and it’s how effectively your skin is protected against harmful UVB rays, which help to prevent skin damage (burning leads to sensitivity, premature ageing and brown spots) that can lead to more serious skin conditions such as skin cancer.


#2 What SPF should I be using?

The easy answer is anything above SPF 30 because it blocks 97% of UVB rays. And, if you’re looking for maximum protection choose a broad spectrum, SPF 50, which blocks 98% (so there’s actually only 1% protection between them!).

Note: For a high protection SPF, take a look at the Ultrasun collection, which features a wide selection of Broad Spectrum sunscreen.


#3 What is broad spectrum SPF?

Broad-spectrum is a must for all-round protection. It protects you from the main two types of UV rays, UVB and UVA (both are not good for the skin). It also protects against HEV rays (High Energy Visible Light) produced by the sun, your phone, tablet or computer, which means it can reach you at all times of the day (if you struggle with hyperpigmentation, HEV rays are something to look out for).

FDA approved, Broad-Spectrum means that it contains UVA protection equivalent to its UVB. And, if it’s not broad-spectrum, it means you won’t be protected against UVA rays.


#4 What’s the difference between UVB and UVA rays?

UVB, also known as ultraviolet B short-wave rays, penetrate the first level of the epidermis and are responsible for skin burning. In short, if you don’t want to become red, burnt and sore from the sun, you need to get an SPF 30 or higher to keep you protected from harmful UVB rays.

Tip: An easy way to remember UV-B – “B” is for burn.

Where to find: you can usually find the level of UVB protection on the front next to or under the factor rating.


Worried about premature ageing? UVA protection is the one to watch. UVA rays are long-wave rays that penetrate deeper into the epidermis, causing premature ageing such as wrinkles, dark spots, loss of elasticity and firmness. Unlike UVB, UVA rays can penetrate through glass, which means that they can still affect you while you’re inside or driving.

Tip: A good way to remember UV-A – “A” is for Ageing.

Where to find: you can usually find the level of UVA protection under or next to the factor rating.


#5 What is PPD?

PPD stands for is persistent pigment darkening, a measurement of protection against UVA exposure. Basically, this means how quickly you tan if you were wearing an SPF (in some countries PPD, is also known as PA+).

Where to find: you can usually find the PPD number on the front or under the ingredient on the back of the label.


#6 What Is PA+?

PA is a protection grade of the UVA in your SPF. You can remember PA by remembering ‘premature ageing’. The letters “PA” are usually followed by plus signs that are ratings (PA+, PA++, PA+++, and PA++++). PA+ offers low UVA protection,  whereas PA++++ offers extremely high protection. As you know UVA penetrates deeper into the skin, causing collagen to break down, and for this reason, a high PA rating is a great option if your main concern is premature ageing.

Where to find: you can usually find the level of PA+ protection next to the SPF rating on the front of the bottle.


#7 What Is UVAPF?

Ultraviolet A Protection Factor, also known as UVAPF is another measurement of UVA protection. But, it has to be labelled differently because whereas PPD and SPF are based on results from humans, UVAPF is measured on the amount of UVA light that passes through translucent plastic.

Where to find: If the brand supplies it you can find it on the front of the SPF. If not, UVAPF is at least ⅓ of the SPF value, so if for instance, it’s SPF 30, you know it’s UVAPF 10.


#8 What is a UVA rating?

The star rating measures the level of protection from UVA light. The scale is from 1 to 5, with 3 stars being good, and 4 to 5 being excellent.

Where to find: you can usually find the UVA rating on the back of the bottle near the ingredients (a circle with UVA, and star symbols to match the rating).

Note: For high UVA protection try out any of Eucerin‘s range of innovative SPFs.


#9 What’s the difference between mineral and chemical, and which one should I use?

Mineral SPF is a physical block UV Filter that sits on top of your skin and protects it by reflecting or blocking the rays. How can you tell if it’s mineral? You’ll spot UV filters titanium dioxide (TiO2) and zinc oxide (ZnO) in the ingredients.

Mineral SPFs


• Photostable, mineral UV filters don’t break down when you’re in the sun
• Zinc oxide is gentler on the skin (good for sensitive, reactive and acne-prone skin types)
• Mineral SPF works straight after applying
• Usually reef-friendly

• It can give the skin a white cast appearance because it sits on top of the skin, (rather than absorbed)
• Titanium dioxide can cause some people to break out. So, if you get spots from using mineral sunscreen and makeup Titanium dioxide is the one to avoid
• Rubs off easier

Note: If you’re looking for a sunscreen high in natural ingredients, you’ll love Clarins’s collection of plant-based SPFs.


Chemical SPFs

Chemical SPF contains chemical active UV Filters such as avobenzone, octocrylene and oxybenzone that work to absorb the sun rays rather than reflect.

• The thinner consistency of chemical sunscreen tends to work better cosmetically, especially worn under makeup.
• Chemical sunscreens tend to offer a wider cover against UVA and UVB.
• Your skincare can be easily applied after.

• You also have to wait 20 minutes for it to fully absorb into the skin before going in the sun.
• Chemical sunscreens are more irritating for the skin, and can sometimes cause allergic reactions. (If your skin is sensitive, try minerals first.)
• Most are photostable, but not all are. If you don’t want to constantly be reapplying watch out for unstable chemical ingredients like Avobenzone, which break down in sunlight.
• Ingredients commonly found in chemical SPFs such as oxybenzone and octinoxate are linked to coral bleaching.

Note: If a reef-friendly SPF is your main concern, then try Caudalie and Avene for SPF that are made to respect marine biodiversity.


Over to you!

Have you got any questions? Tweet me for an instant answer, or comment below and I’ll get back to you there.


Discover more:

5 SPFS for People Who Hate Wearing Sun Cream
The Best Facial SPF Mists You’ll Actually Want To Wear

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