Nano and Ultrafine Zinc Oxide as a UV Filter: What EU Annex VI Actually Says

Zinc oxide (CAS 1314-13-2) sits in EU cosmetics law under three separate entries at once: two in Annex VI as a UV filter, one in Annex IV as a colorant. Suppliers and formulators often describe the fine-particle grade as "ultrafine" or "micronised" zinc oxide, but neither term has any legal standing in the EU Cosmetics Regulation. What has legal standing is whether a given batch meets the definition of "nanomaterial" in Article 2(1)(k), and, separately, whether it meets the narrower physical-characteristic conditions written into Annex VI entry 30a. This article is about how those legal categories are built, not about sunscreen safety or SPF performance.

"Nanomaterial" Is a Legal Term. "Ultrafine" and "Micronised" Are Not

Article 2(1)(k) of Regulation (EC) No 1223/2009 defines "nanomaterial" as "an insoluble or biopersistant and intentionally manufactured material with one or more external dimensions, or an internal structure, on the scale from 1 to 100 nm." That is the only definition that carries legal weight under EU cosmetics law. The regulation also allows the Commission to adjust this definition to technical and scientific progress and to definitions agreed at international level (Article 2(3)).

"Ultrafine zinc oxide" and "micronised zinc oxide" are industry and marketing descriptions of particle size, used inconsistently across suppliers and safety data sheets. Neither term appears in Regulation 1223/2009 and neither automatically maps onto "nanomaterial" or onto the Annex VI nano entry. A grade sold as ultrafine could be below, at, or above the 1-100 nm nanomaterial scale, and even if it is within that scale it may or may not match the additional conditions Annex VI sets for zinc oxide specifically. The only reliable test is the substance's own measured particle size distribution, crystal structure and other properties checked against the Annex VI text, not the name on a supplier's spec sheet.

Two Annex VI Entries for One CAS Number

Annex VI is the EU's positive list of substances permitted as UV filters in cosmetic products; the current list holds 33 entries (cosingchecker.com/annex/VI/). Zinc oxide is covered by two of them:

• Entry VI/30, "Zinc oxide" - the non-nano form
• Entry VI/30a, "Zinc oxide (nano)" - the nanomaterial form

Both entries carry the same maximum concentration: 25%, with a combined-use condition that if both the non-nano and the nano form are used in the same product, their sum must not exceed 25%. Both entries also carry the same restriction on application: "Not to be used in applications that may lead to exposure of the end-user's lungs by inhalation." That wording excludes spray and powder formats capable of reaching the lungs from both entries' authorisation, whether the zinc oxide used is nano or not.

What Makes a Zinc Oxide "Nano" Under Annex VI

Entry VI/30a does not authorise any zinc oxide particle merely because it falls under 100 nm. It authorises only nanomaterial zinc oxide meeting a specific set of physical-characteristic conditions written into the entry itself:

• Purity of at least 96%, wurtzite crystalline structure, physical appearance as clusters that are rod-like, star-like and/or isometric shapes, with impurities limited to carbon dioxide and water and any other impurities below 1% in total
• Particle number size distribution: median diameter D50 (50% of particles below this size) greater than 30 nm, and D1 (1% below this size) greater than 20 nm
• Water solubility below 50 mg/L
• Uncoated, or coated with one of four named substances only: triethoxycaprylylsilane, dimethicone, dimethoxydiphenylsilane/triethoxycaprylylsilane cross-polymer, or octyltriethoxysilane

A zinc oxide that is nanoscale but fails any part of this bundle - the wrong crystal structure, an uncoated form that isn't listed as an allowed exception, a size distribution outside the D50/D1 window - is not covered by entry VI/30a and has no separate Annex VI authorisation as a UV filter in that form. The bundle is what "nano zinc oxide" means in this specific regulatory context; it is narrower than the general Article 2(1)(k) nanomaterial definition.

The Same Substance Also Has a Colorant Entry

Zinc oxide is separately listed in Annex IV, the EU's positive list of permitted colorants (cosingchecker.com/annex/IV/), as entry IV/144, identified there by Colour Index number CI 77947. Annex IV currently holds 154 colorant entries. The Annex IV entry for zinc oxide carries no maximum concentration figure, but it repeats the same restriction found in the UV filter entries: not to be used in applications that may lead to exposure of the end-user's lungs by inhalation.

One CAS number, three separate legal identities: non-nano UV filter (VI/30), nano UV filter (VI/30a) and colorant (IV/144, CI 77947), each with its own conditions and none interchangeable with another. The zinc oxide ingredient record, with links to all three entries, is at cosingchecker.com/ingredients/38968-zinc-oxide/.

Labelling: The "[nano]" Requirement

Article 19(1)(g) of Regulation 1223/2009 states: "All ingredients present in the form of nanomaterials shall be clearly indicated in the list of ingredients. The names of such ingredients shall be followed by the word 'nano' in brackets." A product formulated with the entry VI/30a grade must show the ingredient with a bracketed nano marker in its ingredient list; "ultrafine" or "micronised" on a label is a marketing choice, not a substitute for it. Non-nano zinc oxide used under entry VI/30 does not take the bracket - including in a product where nano zinc oxide is also present and does take it.

Notification: Article 16 and Its UV-Filter Carve-Out

Article 16 sets a general notification duty for cosmetic products containing nanomaterials: the responsible person must notify the Commission electronically at least six months before the product is placed on the market, with information on identification, particle specification, estimated annual quantity placed on the market, toxicological profile, safety data and reasonably foreseeable exposure conditions.

But Article 16(2) carves out an exception: "The provisions of this Article do not apply to nanomaterials used as colourants, UV-filters or preservatives regulated under Article 14, unless expressly specified." Zinc oxide (nano) used as a UV filter is regulated under Article 14 through Annex VI entry 30a, so the general Article 16 notification route does not apply to it unless the Annex VI entry itself expressly requires it - and, as recorded, entry 30a does not add such a requirement. For nano zinc oxide used as a UV filter, the operative control point is compliance with entry VI/30a's own conditions, not a standalone Article 16 filing.

The SCCS Opinions Behind the Entries

Both Annex VI zinc oxide entries carry references to opinions of the Scientific Committee on Consumer Safety (SCCS) and its predecessor committees, as recorded against the entries: an opinion and statement on zinc oxide used in sunscreens, an opinion on the safety of nanomaterials in cosmetic products, a clarification of an earlier SCCNFP opinion on zinc oxide, and an addendum to opinion SCCS/1489/12 specifically addressing zinc oxide's nano form. The physical-characteristic bundle written into entry VI/30a - purity, crystal structure, particle size distribution, solubility, permitted coatings - reflects the particular grades the SCCS assessed in those opinions. A grade with different physical characteristics has not been assessed under this entry and has no basis for relying on it.

A Verifiable Difference: The US Record Covers Only a Color Additive

Cosingchecker's jurisdiction data for zinc oxide's US record returns a single entry: the FDA color-additive listing at 21 CFR 73.2991, which permits zinc oxide "in amounts consistent with good manufacturing practice" for coloring purposes, including in eye-area cosmetics, with no maximum concentration figure and no nano-specific particle size, crystal structure or coating conditions comparable to EU Annex VI entry 30a. That is a difference in the data cosingchecker holds for the US color-additive framework specifically; it describes what this site's US dataset contains, not the complete body of US law on zinc oxide in every regulatory context outside that dataset.

What This Record Is and Isn't

An Annex VI or Annex IV entry for zinc oxide is evidence of the substance's identity and the conditions attached to a specific use - it is not a safety verdict and not permission to use any particular product formulation. Absence of a condition from these entries is not proof that no condition applies; it means the condition is not recorded in this entry. Readers assessing a specific formulation should check the current consolidated Annex VI and Annex IV text on EUR-Lex directly, alongside the SCCS opinions cited against the entry, rather than relying on any single secondary source, including this one. For the full list of substances permitted as UV filters beyond zinc oxide, see the separate overview of Annex VI.

Sources

• Regulation (EC) No 1223/2009, Article 2(1)(k), Article 2(3), Article 16, Article 19(1)(g) - https://health.ec.europa.eu/system/files/2016-11/cosmetic_1223_2009_regulation_en_0.pdf
• Regulation (EC) No 1223/2009, consolidated text - https://eur-lex.europa.eu/legal-content/en/TXT/?uri=CELEX%3A32009R1223
• Commission Regulation (EU) 2016/621 amending Annex VI to Regulation (EC) No 1223/2009 - https://eur-lex.europa.eu/legal-content/EN/TXT/HTML/?uri=CELEX:32016R0621
• CosIng Checker, Annex VI (UV filters) - https://cosingchecker.com/annex/VI/
• CosIng Checker, Annex IV (colorants) - https://cosingchecker.com/annex/IV/
• CosIng Checker, zinc oxide ingredient record - https://cosingchecker.com/ingredients/38968-zinc-oxide/
• CosIng Checker API, entries by CAS 1314-13-2 - https://cosingchecker.com/api/v1/entries/?cas=1314-13-2
• CosIng Checker API, zinc oxide jurisdictions - https://cosingchecker.com/api/v1/ingredients/38968-zinc-oxide/jurisdictions/
• CosIng Checker API, site stats - https://cosingchecker.com/api/v1/stats/
• US FDA, 21 CFR 73.2991 color additive zinc oxide - https://www.ecfr.gov/current/title-21/chapter-I/subchapter-A/part-73/subpart-C/section-73.2991