Almost every argument in the natural sun care category runs aground on a point of law that is not difficult and is rarely stated. A sunscreen sold in Great Britain is a cosmetic product. Cosmetic products may only contain ultraviolet filters that appear on a specific published list. That list is closed. If a substance is not on it, the substance is not a UV filter for regulatory purposes, whatever it does in a beaker.
The legal frame in one paragraph
Great Britain applies the Cosmetic Products Regulation, retained after EU exit as assimilated law and amended since. It sets out a general safety obligation, a requirement for a product information file and a safety assessment by a qualified assessor, notification before a product is placed on the market, labelling rules, and a set of annexes. Two of those annexes matter here. One lists substances prohibited in cosmetic products. Another lists the UV filters that are allowed, with the maximum concentration and any conditions attached to each entry. Enforcement sits with the Office for Product Safety and Standards at national level and with local authority Trading Standards services in practice.
Nothing in that structure makes a sunscreen a medicine. This is a genuine difference from the United States, where sunscreens are regulated as over the counter drugs, and it explains why the two markets have different filter lists and why importing a product from one to the other is not a simple matter. It also explains a persistent piece of confusion: the UK does not have a small permitted list because of caution. It has a list because the whole regulation works by positive listing.
What it takes to get on the list
A substance reaches the annex through a dossier. A manufacturer compiles physicochemical characterisation, purity and impurity data, ultraviolet absorption spectra, dermal absorption studies, toxicological studies covering acute and repeated dose toxicity, genotoxicity, and where relevant reproductive toxicity, phototoxicity and photogenotoxicity, and an exposure assessment. In the European system, the Scientific Committee on Consumer Safety reviews that dossier and issues an opinion. Listing follows, sometimes with conditions, sometimes with a lower concentration than requested, sometimes not at all. The process is slow, expensive and adversarial in the specific sense that the committee will ask for more data rather than assume the best.
This is the single most useful fact for anyone assessing the natural category. Every filter you are permitted to use has been through that. No plant oil has. That is not a conspiracy against botany, and it is not evidence that plant oils fail such a review. It is that nobody has run one, because there is no commercial route to recovering the cost of assessing a commodity oil that any competitor could then use.
The two mineral entries
Metal oxide filters
Zinc oxide; Titanium dioxide (both also listed in nanomaterial forms with separate conditions)Inorganic semiconducting particles, dispersed in the product rather than dissolved. Supplied as surface treated powders or as pre made dispersions in oil or water.
Attenuate ultraviolet radiation, predominantly by absorption across the band gap of the semiconductor, with a smaller contribution from scattering that depends strongly on particle size.
Loading is limited in practice by texture, whiteness and rheology long before the legal maximum is reached. Both are hard to keep dispersed and both interact with other formulation components.
Long term behaviour of the nanoscale forms in the environment; whether coatings remain intact through a product's life; and how the absorption to scattering ratio shifts as particles agglomerate on skin.
Both metal oxides appear on the permitted list, and both appear again as separate entries in their nanomaterial forms with conditions attached. The conditions typically concern the physical characteristics of the particles, their surface treatment, their purity and photocatalytic activity, and the forms of application for which they may be used. That last point matters: scientific opinions have advised against use in applications that could be inhaled, which is why the sprayable and loose powder question is treated differently from a cream.
The organic entries, briefly
The rest of the annex is organic chemistry: carbon based molecules that absorb ultraviolet photons through their conjugated electron systems. They fall into recognisable families. Cinnamates and salicylates are small, oil soluble and mainly active in the ultraviolet B region. Dibenzoylmethanes provide long wave ultraviolet A absorption and are photolabile, which is why they are always stabilised. Benzotriazoles and triazines are large, modern, broad in coverage and poorly absorbed through skin because of their size. Sulfonic acid derivatives are water soluble and used to build the aqueous phase of a formula. Camphor derivatives sit between these groups.
This publication uses International Nomenclature of Cosmetic Ingredients names throughout and does not use the trade names that suppliers attach to individual filters, because those are brands and this publication names no brands. The regulatory annex, the ingredient list on a pack and the scientific literature all use the same nomenclature, so nothing is lost.
What a permitted list does not do
It does not rank filters. It does not describe them as safe in the abstract; it describes them as acceptable under stated conditions of use, in a product whose safety assessor has signed off the whole formula. It does not guarantee that a product containing only listed filters performs. And it does not say anything at all about whether a filter is natural, sustainable, marine friendly or suitable for a particular skin. Those are separate questions, most of them handled by advertising law rather than by cosmetics law.
Mineral sunscreen is the only kind that is properly regulated
- What would have to be true
- That mineral filters were subject to a different or more demanding approval route than organic filters.
- That some organic filters on the market had escaped assessment, or were permitted by default rather than by decision.
- What is established
- Every UV filter permitted in Great Britain, mineral or organic, sits on the same annex, reached through the same dossier and opinion process.
- Both metal oxides have been through scientific committee review, as have the organic filters, and several entries have been amended as new data arrived.
- What is not established
- No regulatory instrument treats mineral filters as a distinct or superior class.
- There is no separate, lighter approval route for organic filters that a mineral formulation avoids.
Where this leaves the natural category
A product marketed as natural or mineral in Great Britain is, in filter terms, using one or both of two permitted inorganic entries. Everything else that distinguishes it is the rest of the formula: the emollients, the emulsifiers, the film formers, the preservative system, the fragrance if any. Those choices are real and they can be argued for on their own merits. What cannot be argued is that the product occupies a different legal or scientific category. It occupies a corner of the same list.
That framing runs through the rest of this section. The difference between mineral and organic filters is real but narrower than the marketing suggests. The word chemical as a sorting term does no work at all. And what a filter does to a photon, covered in how UV filters work, is the same physics in both cases.
This publication does not assess or recommend products, and it publishes no rankings. It examines the chemistry of a category and the claims that category makes. Where a question is clinical rather than chemical, it stops and says so.
Checking any of this for yourself
The permitted list is public. The consolidated text of the regulation as it applies in Great Britain is on the legislation website, annexes included, and the government publishes guidance on placing cosmetic products on the GB market. Scientific committee opinions are published in full, including the reasoning and the data gaps that the committee identified. If a claim about a filter cannot be traced to one of those, it is worth asking where it came from.