Mineral vs chemical sunscreen filters: what the names mean

Two families of UV filter

EU law defines UV filters as substances meant mainly to protect the skin against certain UV radiation by absorbing, reflecting or scattering it (Article 2(1)(n)).¹ They come in two families. The FDA describes zinc oxide and titanium dioxide as inorganic, or physical, UV filters made of metal oxides, and oxybenzone, for example, as an organic, or chemical, filter that absorbs UV radiation.² The EU's ingredient database likewise describes Zinc Oxide and Titanium Dioxide as inorganic oxides.³⁴

"Mineral" and "chemical" are shorthand: both families are chemical substances. On the EU's list of permitted UV filters, titanium dioxide and zinc oxide are the two inorganic ones; the others, from Octocrylene to Butyl Methoxydibenzoylmethane, better known as avobenzone, are organic compounds.¹

How they work, as far as sources say

The FDA's 2019 proposal says sunscreen active ingredients protect by absorbing, reflecting and/or scattering radiation in the UV range, from 290 to 400 nanometres, and describes the two metal oxides as filters that primarily reflect or scatter UV radiation. It adds that zinc oxide's ability to reflect UVA is why it is frequently used to help give broad-spectrum protection.²

Measurement tells a more complicated story. A 2016 study, by authors from a consultancy and a consumer products company, measured how much UV titanium dioxide and zinc oxide transmit and reflect. Across the UV range they reflected only 4-5% on average; the rest of the protection they gave came from absorption, through their properties as semiconductors. Only at longer wavelengths, in the long UVA and visible range, did they act mainly as reflectors, at up to 60%.⁵ On that evidence, "minerals reflect, chemicals absorb" is a simplification.

Particle size changes how they look. The FDA notes that zinc oxide particles larger than about 100 nm can give a product an opaque, white colour, and that smaller particles are made to reduce it; titanium dioxide is likewise made at 15 to 50 nm to reduce its white appearance.² That is where nano forms come in, covered below.

Mineral and chemical filters side by side

In the EU: Annex VI and its limits

In the EU a sunscreen is a cosmetic⁸, and a cosmetic may contain only the UV filters listed in Annex VI, used within that annex's conditions (Article 14(1)(e)). Each entry sets a maximum concentration in the ready-for-use product, and some add limits by product type.¹ The sunscreen active ingredients guide lists the common filters with their entries and limits.

In the US: sunscreens are drugs

In the US, sunscreens are regulated as over-the-counter drugs.⁹ The monograph that came into being with the CARES Act in 2020 listed 16 active ingredients, among them zinc oxide and titanium dioxide at up to 25% each.⁶¹⁰

In 2019 the FDA proposed new conditions, carried into a 2021 proposed order that is substantively the same. It proposed that sunscreens containing zinc oxide or titanium dioxide, at up to 25%, are generally recognised as safe and effective (GRASE); that those with PABA or trolamine salicylate are not, because of safety concerns; and that twelve other ingredients, including avobenzone, octocrylene, homosalate and oxybenzone, need more data. The FDA says this is not a conclusion that those twelve are unsafe: it asked for data so that it can evaluate them.⁶

Two changes have followed. In June 2026 the FDA added bemotrizinol at up to 6%, the first new active ingredient in the sunscreen monograph since the late 1990s¹¹⁷; EU labels call it Bis-Ethylhexyloxyphenol Methoxyphenyl Triazine (Annex VI, entry 25).¹ In September 2026 it issued a final order removing PABA and trolamine salicylate from the monograph, and the FDA says it will address the other proposals in future orders.⁶

Nano forms and the (nano) label

EU law defines a nanomaterial as an insoluble or biopersistent, intentionally manufactured material with one or more external dimensions, or an internal structure, on the scale from 1 to 100 nm (Article 2(1)(k)). An ingredient present as a nanomaterial must be followed by the word "nano" in brackets on the ingredient list (Article 19(1)(g)).¹

The annexes do not cover nanomaterials unless an entry says so (Preamble to Annexes II to VI, point 3), so a nano filter needs an entry of its own. Titanium Dioxide (nano) and Zinc Oxide (nano) each have one, with conditions on purity, particle size and coatings, and neither may be used in applications that may lead to exposure of the user's lungs by inhalation (Annex VI, entries 27a and 30a).¹ The Titanium Dioxide page sets out its entry in detail.

On the label

• EU: the filters are part of the ordinary ingredient list, by weight and without percentages. Look for Annex VI names: Zinc Oxide and Titanium Dioxide for the minerals, names such as Octocrylene for the rest.¹
• US: the filters are the active ingredients in the Drug Facts box, each with its percentage.¹²
• (nano) after a name: the filter is present as a nanomaterial.¹
• "Mineral" on the front of a pack is the brand's description. The list shows whether an organic filter is in there as well.

Neither family is a verdict on a sunscreen, and no list tells you how well a product protects: that is measured by testing the finished product.⁸ To see every filter on a list at once, paste it into the skincare ingredient checker.