How to Choose Sunscreen: SPF, UVA & UVB Protection & What the Labels Really Mean
As a holistic facialist, I'm often asked for advice on sunscreen. To keep up to date, I've trawled through the latest fact-based research in an industry that is forever changing and advancing. Here, I'm sharing the results. Sources include the NHS, Met Office, British Association of Dermatologists, British Beauty Council, Cosmetic Toiletry & Perfumery Association, Which?, skincare charity MSCED , Leaping Bunny, Science Direct, clinical studies and more.
How Sunscreens Work
There are two main classifications of UV filter and many sunscreens today contain a combination of both. They work in similar, but slightly different ways.
“Mineral” filters (often called "physical" in the past). In chemistry, "inorganic" refers to substances that do not contain carbon-hydrogen bonds. Zinc oxide and titanium dioxide are inorganic chemicals that act as sun filtes to primarily absorb UV radiation and convert it into harmless heat, so that skin cells are not damaged. There is also a smaller contribution from scattering and reflection of UV rays. More recently, these filters are engineered into microscopic particles that don't leave an old-fashioned white cast on the skin - these are called nano particles.
"Chemical” filters are carbon-based molecules and in chemistry are known as “organic”. Examples of older generation chemical filters are avobenzone, oxybenzone, octisalate and octinoxate. More recent advances have seen 'new/next generation' filters with greater photostability entering the market, such as Bemotrizinol (Tinosorb S) and Bisoctrizole (Tinosorb M).
How to Choose Your Sunscreen
Some factors in decision making when choosing sunscreen include the level of protection (SPF, UVA & UVB), skin & eye sensitivity, texture and feel, ethics around environmental protection & animal testing, health concerns, brand reputation & cost. We'll touch on some of these briefly below.
Level of Protection
To protect you adequately, sunscreen should offer broad-spectrum protection including adequate UVA coverage and at least SPF 30 or SPF 50 for UVB protection.
When you choose a product, the packaging should indicate the protection level from both UVA and UVB. If this information isn't available, it's harder to judge how much UVA protection it provides. So be cautious about products called "SPF moisturiser" and always check for a clear indication of UVA protection.
UVB: The SPF number (Sun Protection Factor) indicates protection against UVB, which primarily causes sunburn and contributes to skin cancer. The number measures how much longer skin is protected compared to no sunscreen. Choose SPF 30 or higher. SPF30 filters out about 97% of the sun's rays while for SPF50 it's about 98%.
UVA: Protection from UVA radiation is equally as important as UVB, as this penetrates deeper into the skin, contributing to ageing, DNA damage and skin cancer. Look for one of these alongside your SPF:
⭕ UVA
★★★★★
PA++++
BROAD SPECTRUM
These classifications are all different because regulation differs across the globe. Sunscreens in the UK & EU come under the scope of "cosmetic products" & have a similar precautionary cosmetic safety system. In the US, sunscreens are regulated as "over-the-counter drugs" & in Australia as "therapeutic goods." In Asia the categorisations vary. So decoding labels can only be done when you understand the symbols. Here's what they mean:
· The UVA circle logo ("UVA" letters enclosed in a circle) is a standard marking on sunscreen packaging indicating that the product meets the European Commission's minimum standard for UVA protection (the 1/3 rule where the product's UVA protection factor must be at least one third of its labeled SPF). A product displaying SPF30 or SPF50 along with the UVA in a circle symbol is a good indication that the product meets the European minimum standard for UVA protection relative to its SPF.
· The UVA star rating (up to 5 stars *****) pioneered by Boots and common in the UK, indicates the balance between UVA & UVB protection. Preferably, choose at least SPF30 and 5 stars displayed together.
· The PA system (Protection Grade of UVA up to PA++++) originating in Japan & Korea is based on the Persistent Pigment Darkening (PPD) method, which tests how much UVA exposure is required to cause persistent pigment darkening in skin. This is indicated by the letters PA and then up to ++++ with 4 being the highest protection. The PA system is independent of the SPF rating. SPF30 or 50 alongside PA++++ is preferable.
· In Australia & the US, sunscreen shows the words “Broad spectrum” to indicate protection against both UVA and UVB is present. However this is based on different regulatory testing with Australia requiring UVA protection to scale proportionally with SPF, while the US uses a “critical wavelength test” (at least 90% of the sunscreen's total UV protection must cover wavelengths up to 370 nm for adequate UVA coverage). The US system doesn’t use the 1/3 rule and so is less rigorous.
Additionally, if you see the term "broad spectrum" used in general terms, this simply means that a product contains both UVA & UVB protection, but it doesn't guarantee specific levels.
Use by dates: Sunscreen use-by dates also matter, as efficacy can decline after expiry. Take a note of the use-by date or PAO (Period-after-opening symbol - an open jar that gives an indication of how many months to keep a product after opening). Storage away from heat, such as in hot cars, is also important.
Skin/eye sensitivity
True sunscreen allergy is rare, but irritation and sensitivity reactions to sunscreen are relatively common. If you have eczema-prone, reactive or highly sensitive skin, choosing your sun protection is often trial and error. Some people find that mineral sunscreen is less likely to cause a reaction. Scientific sources behind patch testing for sunscreen allergens show chemical filters, especially the older ones such as oxybenzone (benzophenone-3) and octinoxate (ethylhexyl methoxycinnamate) may be problematic for some people, although there are newer generation sunscreens that may be well tolerated. Get to know your triggers and keep a list of anything you wish to avoid. The only way to be absolutely sure of ingredients is to study the INCI list (International Nomeclature of Ingredients) on the product packaging.
If you’re unsure about a product, seek out trusted reviews from real customers (not incentivised with free products). Read the one star reviews as well as the 5 stars.
Ethics about environmental protection
Increasingly we hear that certain sunscreen ingredients are potentially harmful to the planet. Some places such as Hawaii have banned chemical sun filters oxybenzone and octinoxate to protect coral reefs and some sunscreens call themselves 'marine-safe', although it's not a regulated term. The environmental effects of sunscreen ingredients including nano mineral particles remain an area of active research.
There's plenty to read online if you're interested. Originating in the US, the "HEL" list was created by the Haereticus Environmental Laboratory (a non-profit scientific organisation). It identifies chemical ingredients that act as acute toxins or endocrine disruptors in marine life, freshwater streams, rivers, and coral reefs.
Ethics about animal testing
If we care about animal testing, we can’t always rely on brand owners to be transparent. Sunscreens sold in China may still require animal testing under certain regulatory pathways.
As well as reading brand statements I like to check independent databases to discover whether brands or their parent companies support animal testing. Look at Leaping Bunny, Peta and Cruelty-free Kitty for reliable information.
Health concerns
Another complex subject worth being aware of is whether certain ingredients may have wider implications for health. For example, the EU has prohibited 4-MBC (4-Methylbenzylidene camphor, or enzacamene) in cosmetics and the UK is aligning. This is an organic UVB filter compound with endocrine-disrupting potential and insufficient safety data regarding genotoxicity. Certain other ingredients continue to be under review, such as octocrylene.
Brand Reputation
Recently there have been some independent reports of sunscreens not performing as indicated, which led to some brands disputing the testing & others withdrawing products. Separating headlines from factual evidence isn’t always easy, so choosing how to read these reports is another personal choice.
Cost
You can pay £5 or £50 for your sunscreen, so it all depends on your budget and your criteria.
In the UK sunscreen is still classed as a cosmetic, so we pay standard VAT. There are campaigns being run by charities and other organisations to remove this tax, but in the meantime you can often find retailers offering 20% off sunscreen as a matter of principle, or as a promotion.
How To Apply
Sunscreen is needed when the skin is exposed to UV light. This includes when you’re sitting by a window or driving, as UVA penetrates glass.
Sunscreen needs an even, uninterrupted layer to work properly. Clean your skin & moisturise first, then apply sunscreen as the final step of skincare before makeup. If you wish to wear foundation or tinted moisturiser on top of your sunscreen, you can apply this very lightly once the sunscreen has ‘set’. Never mix your sunscreen with other products as this reduces its effectiveness. Reapply sunscreen approximately every 2 hours and after swimming/sweating, as it gradually wears away.
Never rely just on sunscreen. Hats, protective sunglasses, staying out of the sun especially during peak hours - all of these are important, too.
An easy way to remind yourself whether sunscreen is necessary is to look at The Met Office website or download their app. They have a useful UV index showing radiation levels on any given day. Even when it's cloudy the UV can be high, so just look up the weather for your location & you’ll be given a rating and advice.
Thank you for reading & enjoy the outdoors!
Lucy Stevens MFHT
April 2026 updated June 2026
References
If you’d like a list of references for this blog, do get in touch.
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