The category that calls itself natural, taken at its word
A field guide to mineral and natural sun care, written for readers who prefer this kind of product and would rather have the chemistry stated than flattered. What the permitted filters actually are, what zinc oxide and titanium dioxide actually do, and which of the category's claims survive being set against the evidence. No brands, no products, no rankings, and no money from anyone selling sun care.
From what a filter is, to what the category says about the sea
The permitted filters
Only substances on a published annex may be used, and no plant oil is among them
02Zinc and titanium
Two metal oxides, examined on their optics, their chemistry and their limits
03The word natural
An undefined word, and the claims that have been built on top of it
04Reefs and the sea
Reef safe has no criteria, and mineral filters are not the free pass they are presented as
05Skin and health
Tolerability, children and vitamin D, with the clinical questions handed over
A claim, what would have to be true, and what is actually established
Every claim examined on this site is recorded with a status word from a fixed published vocabulary. The full register runs to 35 entries.
Which UV filters are permitted in the UK, and how that list works
Sunscreen in Great Britain is a cosmetic product, and only UV filters on a published annex may be used. What that means for the mineral and natural category.
Mineral and organic UV filters: the difference that is real, and the one that is not
The division between mineral and organic UV filters describes a genuine chemical difference. It does not describe a difference in safety, in naturalness or in regulatory status.
Why chemical sunscreen is a category that describes nothing
Every ingredient in every sunscreen is a chemical, including zinc oxide and water. Sorting sunscreens into chemical and non chemical does not describe a real division.
How a UV filter actually works, in both classes
Absorption, scattering and reflection are three different physical processes. Understanding which one a filter relies on explains almost every practical difference between products.
Ultraviolet A, ultraviolet B and what broad spectrum means on a UK pack
The UVA logo in a circle is not decoration. It records a defined relationship between ultraviolet A protection and the sun protection factor, and it applies to mineral products too.
Photostability, and why a formulator never uses one filter alone
A filter that degrades in sunlight stops protecting. Photostability explains why formulations combine filters, and why the mineral category's stability advantage is real but narrow.
What zinc oxide actually does in a sunscreen
Zinc oxide is a semiconductor that absorbs ultraviolet across its band gap. What that means for coverage, for texture and for the rest of the formula.
What titanium dioxide actually does in a sunscreen
Titanium dioxide is the strongest white pigment in industrial use and a competent UV filter. The two facts are connected, and they explain both its strengths and its problems.
Editorial disclosure. This article contains no commercial links. Nothing on it has been paid for, no company has been given sight of it, and no brand or product is named anywhere on this site. This publication takes no money from sunscreen or skincare companies at any price, and the reasons are set out in what we refuse to sell. Published by Northbank Media.
The dispatch
A monthly note: what has been published, what has changed in a claim's status, and one piece of working. It carries a single clearly labelled sponsor line, at a published rate that cannot influence any status recorded here. Unsubscribe whenever you like.
Your address is used for the dispatch and nothing else. See privacy.