Mineral vs Chemical Sunscreen: A UK Guide

Why we stock what we stock

Choosing a sunscreen should be simple. But with terms like mineral SPF, chemical sunscreen and non-nano in circulation, it is hard to know what actually matters for your skin.

When I opened the CONTENT store in 2008, we quickly became a destination for people who found themselves reacting to ingredients in their clean beauty products. I have always enjoyed the detective work of helping customers pinpoint the cause.

Every cosmetic product sold in the UK must pass a safety assessment before it goes on sale, and the great majority of people use synthetic sunscreens with no trouble at all. But a minority do react, and the number of customers telling me about reactions to synthetic filters, some of them severe, was enough to shape what we put on the shelves. I decided early on that mineral sunscreens would be the standard here, so that anyone shopping with a known sensitivity had somewhere to start.

Sunscreen is a complicated category and my position on it has evolved as the sunscreens available have. A handful of newer synthetic filters have proved much better tolerated, and we now stock two of them. What follows is how each type works, what the science currently says, and where the regulations in the UK, the EU and the US diverge, so you can decide for yourself.

One thing is not in question. The sunscreen you will actually wear, every day, is the one that will do you the most good.

What is mineral sunscreen?

Mineral SPF, sometimes called physical sunscreen, uses one or both of two UV filters: zinc oxide and titanium dioxide. These are the only two filters classified as mineral by regulators.

Zinc oxide covers the broadest range of UV wavelengths, with particularly consistent UVA protection. Titanium dioxide skews towards UVB, which is why the two are often paired.

Both mineral and synthetic filters work largely by absorbing UV and releasing it as heat. Mineral filters also reflect and scatter a proportion of UV away from the skin, which synthetic filters do far less of, though absorption does most of the work in both cases. That reflection is also part of why mineral formulas can leave a cast: the same particles bounce back a little visible light along with the UV.

Nano and non-nano: what it means

Nano refers to particle size. Nano particles of zinc oxide or titanium dioxide measure under 100 nanometres; non-nano particles are larger.

UK and EU labelling rules require nano-materials to be declared on the ingredient list, with the word in brackets after the ingredient name, so you can always tell which you are buying:

Titanium Dioxide [nano]
Zinc Oxide [nano]

Smaller particles disperse more finely, which is why nano formulations tend to look sheerer on the skin. Studies of cream and lotion formulations indicate the particles stay on the skin's surface rather than passing through it. The clearer concern is inhalation, which is why loose powder and spray formats containing nano particles carry more scrutiny than creams.

Certified natural does not mean non-nano

This trips people up, so it is worth explaining. Natural and organic certification does not rule nano out of sun care.

COSMOS, the standard that BDIH and the Soil Association feed into, prohibits nano-materials as a general principle. But it made a deliberate exception for mineral UV filters, on the grounds that they meet the standard's requirements for natural ingredients, contribute significantly to sun protection, and have been assessed by the EU's Scientific Committee on Consumer Safety and found to no pass the skin barrier on healthy skin. Certified sun creams may therefore contain nano zinc oxide or titanium dioxide where other certified products could not.

Standards differ from one another, and they change. So if non-nano matters to you, the certification logo is not the thing to read. The INCI list is: look for [nano] in brackets after the filter name, which UK and EU law requires.

Our position: the majority of our sun care is non-nano, with one exception quietly, the Weleda UV Glow Fluid SPF30 combines non-nano zinc oxide with titanium dioxide [nano], and we stock it because a genuinely cast-free mineral fluid solves a real problem for people who would otherwise skip SPF altogether. Everything else in the range is non-nano throughout. Our preference is partly about the inhalation question and partly about the marine research discussed below, where the evidence on nano particles is less settled. It is a buying preference rather than a verdict on safety, and if non-nano matters to you, the ingredient list will always tell you.

But don't mineral SPFs leave a white cast?

They can, though far less than they used to. Roll back to 2008 and I will happily admit mineral sunscreen was hard work: thick, chalky and reluctant to rub in.

Modern formulas use finer dispersions, tinted bases and better emulsifiers to reduce or remove the cast. Many now blend in cleanly and wear comfortably under makeup.

If white cast is your sticking point:

Look for formulas described as sheer, tinted or invisible finish
Tinted versions work hardest on deeper skin tones
Warm the product between your fingers before applying, and apply in thin layers rather than one thick one
Try a sample first; the difference between brands is much bigger than the difference between SPF numbers

What is chemical sunscreen?

What is usually called chemical sunscreen uses synthetic UV filters. They absorb UV radiation and release it as heat, in broadly the same way the mineral filters do.

These formulas tend to be lighter and more fluid, which is why they disappear so well on the skin and why they dominate the mass market. Several of them also deliver excellent, highly photo-stable broad-spectrum protection.

The reasons some people avoid them fall into two categories, and it is worth separating them.

Tolerance. A minority of people react to particular synthetic filters, most often with contact dermatitis. I am one of them. This is a minority experience, not a general risk, but if you are in that minority it matters a great deal.

Absorption. A 2019 study published in JAMA found that four synthetic filters, applied under maximal use conditions, reached plasma concentrations above the threshold at which the FDA would normally require additional toxicology data. The filters were avobenzone, oxybenzone, octocrylene and ecamsule. Importantly, exceeding that threshold triggers a request for more data; it is not a finding of harm. The FDA has said as much, and has asked the industry to supply it.

The synthetic filters you will see most often

All of these are legal in the UK within set concentration limits. Where a filter has been restricted or questioned by a regulator, that is noted; where the evidence is animal data or laboratory work, that is noted too.

Filter	Also listed as	What it does	Current position
Oxybenzone	Benzophenone-3 (the INCI name on UK labels), 2-hydroxy-4-methoxybenzophenone, Escalol 567	Broad UVB and some UVA	Banned in Hawaii and Palau on environmental grounds; a recognised contact allergen; endocrine activity raised in some studies
Octinoxate	Ethylhexyl Methoxycinnamate (the INCI name on UK labels), octyl methoxycinnamate, OMC, Parsol MCX	UVB	Banned in Hawaii and Palau; can cause allergic contact dermatitis in some people
Avobenzone	Parsol 1789	Broad-spectrum UVA	Photolabile unless stabilised by other ingredients; may irritate sensitive skin
Octocrylene	—	UVB and short UVA; stabilises avobenzone	Permitted to 10% in the UK; ECHA has proposed an EU-wide restriction to 0.001%, which would effectively remove it from cosmetics, with a decision not expected before 2027
Homosalate	—	UVB	Restricted in the EU to face products at a maximum of 7.34%; Great Britain has diverged and still permits 10% in all cosmetic products

Homosalate is worth highlighting because it is where the UK and the EU have genuinely parted company. The EU restriction applied to products placed on the market from January 2025 and to products made available from 1 July 2025. Great Britain did not follow it. The UK's Scientific Advisory Group on Chemical Safety in Consumer Products reviewed homosalate in May 2025 and concluded it is safe at up to 10% in all cosmetic products, and the CTPA has confirmed the EU limit does not apply here. A sunscreen sold legally in London may therefore contain more homosalate than the same brand's formula in Dublin.

The newer filters, and why we changed our minds

The filters above are mostly from a past generation. Several have been in use since the 1970s and 1980s, and much of the concern attached to them reflects that age rather than anything unique about synthetics as a class.

A newer generation, developed in Europe, performs considerably better: more photostable, broader spectrum, and better tolerated by sensitive skin and are popping up in clean beauty brands.

Filter	Also known as	Notable for
Diethylhexyl butamido triazone	Iscotrizinol, Uvasorb HEB	Strong UVB protection, high water resistance, photostable
Diethylamino hydroxybenzoyl hexyl benzoate	Uvinul A Plus	Long-lasting UVA protection, photostable, suitable for sensitive skin
Bemotrizinol	Tinosorb S	Broad-spectrum, stabilises other filters
Bisoctrizole	Tinosorb M	Broad-spectrum, both absorbs and scatters

We now stock the first two in a small number of products. In the years we have carried them, we have had no reported reactions. They leave no cast, which makes them a genuine option for deeper skin tones where mineral formulas can still struggle.

If you are shopping and want to know whether a sunscreen uses the newer generation, these names on the INCI list are the signal.

Sunscreen and the ocean

This is the part of the conversation where marketing might have run a little ahead of the evidence, so we want to be careful.

What is established

Oxybenzone and octinoxate have been linked to coral bleaching and to effects on marine organisms in laboratory studies. On that basis, Hawaii and Palau have legislated against sunscreens containing them. If you are travelling to either, you need a formula without both.

A word on names, because this catches people out. Oxybenzone and octinoxate are the American names and will not appear on a UK bottle. UK and EU labels use INCI names, so what you are looking for is Benzophenone-3 (oxybenzone) and Ethylhexyl Methoxycinnamate (octinoxate). Benzophenone-4, -5 and -9 are different ingredients and are not covered by the Hawaii or Palau legislation, so the number matters.

What is not established

Mineral filters are not environmentally neutral. In laboratory experiments, uncoated zinc oxide nanoparticles caused rapid and severe bleaching in Acropora corals by disrupting their symbiosis with zooxanthellae, while two coated titanium dioxide forms tested alongside them did not. The honest summary is that the effect of sunscreen on reefs, relative to warming sea temperatures and agricultural runoff, is still an open research question for every filter type.

What does the phrase "reef-safe" mean

A phrase commonly used by brands that don't contain oxybenzone and octinoxate, it is not a regulated term, there is no agreed standard behind it, and no sunscreen has been shown to be free of any effect on marine life.

What we can tell you instead is that our sun care is free from oxybenzone (Benzophenone-3) and octinoxate (Ethylhexyl Methoxycinnamate), and compliant with the Hawaii and Palau legislation. Where a formula is independently certified as biodegradable, we say which certification and link to it.

That is less catchy than a badge. It also happens to be true.

Why UK and US sunscreens are different

If you have ever bought a sunscreen abroad and found the same brand's formula unrecognisable at home, this is why. The EU and UK regulate sunscreens as cosmetics. The US regulates them as over-the-counter drugs, which means every UV filter must clear a drug approval pathway.

That pathway has moved very slowly. Only zinc oxide and titanium dioxide are proposed as generally recognised as safe and effective; a long list including avobenzone, homosalate, octinoxate, octisalate, octocrylene, oxybenzone and ensulizole sits in a category awaiting more data. In September 2026 the FDA finalised the removal of PABA and trolamine salicylate from the permitted list altogether. No new filter has been added through the monograph route since 1999, which is why several filters used routinely in Europe and Asia, including Tinosorb S and M and the two newer filters we stock, are unavailable in American formulations.

Choosing what's right for you

If this is you	Start here	Why
Known reaction to a synthetic filter	Non-nano mineral	Removes the filter class you react to entirely
Reactive skin, no known trigger	Non-nano mineral, or a newer-generation synthetic	Both are well tolerated; patch test either way
Deeper skin tone, cast is the dealbreaker	Tinted mineral, or a newer-generation synthetic	Newer synthetics leave no cast at all
Wearing SPF under makeup daily	Newer-generation synthetic, or a sheer mineral	Lighter textures layer better
Swimming or sport	Check the water-resistance rating, not the filter type	Both types are formulated for water resistance
Babies and young children	Non-nano mineral cream	Simplest ingredient list; avoid sprays and loose powders for inhalation reasons
Travelling to Hawaii or Palau	Any formula without Benzophenone-3 (oxybenzone) or Ethylhexyl Methoxycinnamate (octinoxate)	This is a legal requirement, not a preference

Two things that matter more than any row in this table: use roughly two fingers' length of product for your face and neck, and reapply throughout the day or after swimming or sweating. Most people apply around a third of the amount the SPF rating is tested at, which means a well-chosen SPF 50 can perform like a modest SPF 15 in practice.

Final thoughts

Mineral and synthetic sunscreens both protect your skin, they differ in how they feel, how individual skin tolerates them, and how different regulators treat them.

We stock our mineral sunscreen collection because of what customers told us over the years, and we have added two newer synthetic filters because they offer real options for people that can't tolerate or do not want to use mineral SPF. If your skin is happy with a formula that is not on our shelves, that is a good formula for you.

According to Cancer Research UK, sun protection is one of the most effective ways to reduce your risk of skin cancer, alongside shade and covering up. The sunscreen that delivers that is the one you will reach for tomorrow morning, and the morning after.

Looking for a mineral SPF?

Browse our sun care collection: mineral formulas and a small selection of newer-generation synthetics, chosen for how they wear, how they are tolerated, and what we can honestly tell you about them.

SHOP SUNSCREEN

Sources