CI Numbers in Cosmetics: How EU Annex IV Colorants Work

A colorant on a European ingredient list rarely has a name you would recognise. Instead you get a five- or six-digit number: CI 77163, CI 19140, CI 42090. That is a Colour Index (CI) number, and it is doing a specific legal job, not a stylistic one. This article explains what the number identifies, why EU law requires it, how to read the columns of an Annex IV entry, and what the site's own Annex IV data shows when you look up real entries — including one case where a well-known colorant is not in Annex IV at all.

What a CI number actually identifies

The Colour Index is a reference database of dyes and pigments, identifying each one by chemical constitution independent of any manufacturer's trade name. It is published by the Society of Dyers and Colourists (SDC) and the American Association of Textile Chemists and Colorists (AATCC); it now exists only online, at colour-index.com, having started as a printed reference in 1924. Each substance gets a Colour Index Constitution Number (the digits used on cosmetic labels, e.g. CI 77163) and, separately, a Colour Index Generic Name that groups it by end use.

For cosmetics, the CI number matters because it is chemically specific in a way common names are not. "Pigment Orange 5" or "Titanium Dioxide" can, in principle, be described loosely; CI 12075 and CI 77891 point to one defined substance each, checkable against the Colour Index's own records and against the CAS and EC numbers that regulators attach to the same entry.

Why EU ingredient lists use CI numbers: Article 19(1)(g)

Regulation (EC) No 1223/2009, the EU Cosmetic Products Regulation, sets the labelling rule in Article 19(1)(g). It requires a list of ingredients on the packaging, and for colorants it adds a distinct convention: colorants other than those intended to colour the hair may be listed in any order after the other ingredients, and "the CI (Colour Index) nomenclature shall be used, where applicable." So a colorant does not need to sit in the list where its concentration would otherwise place it — it can be grouped at the end, by CI number.

The "may contain" / +/- convention for decorative ranges

Article 19(1)(g) also covers a real formulating problem: a decorative product, such as an eyeshadow or lipstick, is often sold in several shades built from a shared base formula with different colorant combinations. Rather than print a separate ingredient list per shade, the same article allows all colorants used anywhere in the range to be listed together, provided the words "may contain" or the symbol "+/-" are added. That is a labelling shortcut, not a safety exemption — every colorant named still has to be one the product is legally allowed to contain.

How to read an Annex IV entry

Annex IV is the EU's list of colorants permitted in cosmetic products generally (as opposed to Annex III, which covers restricted substances including hair-dye colorants, and Annex II, which lists substances banned outright). The site's Annex IV table (cosingchecker.com/annex/IV/) currently holds 154 entries, each built from the same fields as the official annex: a reference number; substance identification, including the CI number and, where assigned, CAS and EC numbers; colour; field of application and, where the entry restricts it, product type or body part; maximum concentration in the ready-for-use preparation; other conditions; and the wording of any required warning.

In practice, most Annex IV entries carry only some of those fields filled in. Of the 154 entries the site holds, 60 carry a stated field-of-application or concentration condition and 53 carry an explicit warning or purity note; the rest are permitted with no extra condition beyond the general restriction to genuine, correctly identified CI substances. Reading only one field — say, just the CI number — is not enough: a colorant can be permitted in general but excluded from a specific use.

Field-of-application conditions: what actually appears

Checking the site's Annex IV data directly (rather than assuming a fixed wording) turns up three recurring field-of-application conditions attached to individual entries: "Rinse-off products" (or "Rinse-off product"), "Not to be used in products applied on mucous membranes", and "Not to be used in eye products". These are exactly the kind of restriction formulators need to check before using a colorant in a leave-on eye product versus a rinse-off shampoo, and they only apply to the specific entries that carry them — most Annex IV colorants have no field-of-application limit at all.

Purity is the other recurring condition. Many Annex IV entries — largely the food-colour-derived ones — carry a warning that reads "Purity criteria as set out in Commission Directive 95/45/EC", followed by the matching E-number (for example CI 15985 ties to E 110, CI 19140 to E 102, CI 75470 to E 120). A smaller group of entries set their own numeric purity limits instead: CI 20040, CI 21100 and CI 21108 each cap the 3,3'-dimethylbenzidine impurity at 5 ppm; CI 77510 must be free from cyanide ions; CI 77288 and CI 77289 must be free from chromate ion.

Worked example: CI 12075, and why it is not on Annex IV

CI 12075 is worth checking carefully because assuming it belongs on Annex IV would be wrong. The site's own record (cosingchecker.com/annex/II/ii-397-...) places CI 12075 on Annex II — the list of substances prohibited in cosmetic products — not Annex IV. The entry identifies it as "Colouring agent CI 12075 (Pigment Orange 5) and its lakes, pigments and salts", chemical name 1-[(2,4-dinitrophenyl)azo]-2-naphthol, CAS 3468-63-1, EC 222-429-4, Annex II entry 397, under Regulation (EC) No 1223/2009. The prohibition covers the colorant together with its lakes, pigments and salts, so a formulation cannot route around the ban by using a lake form of the same CI number.

That is the practical lesson: a CI number tells you which chemical substance is meant, but it does not tell you, on its own, whether the substance is allowed, restricted, or banned. The same identifier scheme is used across Annex II, Annex III and Annex IV, and a colorant can only be checked by looking at the annex it actually appears in — the site's search (cosingchecker.com/search/) is built to surface whichever annex a CI number is found on, rather than assuming it is on Annex IV by default.

Worked example: CI 77163, bismuth oxychloride

CI 77163 is on Annex IV, entry 123 (cosingchecker.com/annex/IV/iv-123-ci-77163/). The site records the chemical name as Bismuth chloride oxide, CAS 7787-59-9, EC 232-122-7, colour White, last updated 14 August 2020. This is the CI number generally associated with bismuth oxychloride, the pearlescent pigment used in eyeshadows and highlighters. The site's Annex IV record for this entry carries no stated field-of-application restriction, maximum concentration or purity note beyond the general Annex IV requirement that the substance match the identity given — so any specific concentration or use limit a formulator needs should be confirmed against the current consolidated EUR-Lex text of Annex IV, not assumed from the absence of a note in this record.

Worked example: CI 77891, titanium dioxide

CI 77891 is Annex IV entry 143 (cosingchecker.com/annex/IV/iv-143-titanium-dioxideci-77891/), chemical name Titanium Dioxide, CAS 13463-67-7, EC 236-675-5, colour White, last updated 21 June 2021. This entry is a good illustration of a multi-condition record: the site's "warnings" field carries two separate conditions — purity criteria as set out in Commission Directive 95/45/EC (the same purity standard used for food colour E 171), and a specific rule that titanium dioxide in powder form containing 1% or more of particles with aerodynamic diameter ≤ 10 μm must be used in compliance with Annex III, entry 321 (the entry that restricts titanium dioxide powder in loose face powders and hair aerosol sprays because of inhalation exposure). The record also cross-references Annex VI, entry 27, for titanium dioxide's separate approval as a UV filter — the same CI number and substance appears in more than one annex depending on the function it performs in the product.

A newer Annex IV entry shows the fuller structure: CI 77820

Most Annex IV entries in the site's data leave the product-type and body-part fields empty, meaning the colorant is permitted across cosmetic product types generally, subject only to whatever field-of-application or purity condition is stated. One current exception is CI 77820 (silver powder, entry 142, added by Regulation (EU) 2026/78, last updated 15 January 2026), which shows the fuller Annex IV table structure at work: product type restricted to "(a) Lip products" and "(b) Eye shadow", maximum concentration "For (a) and (b): 0,2%", plus the same Commission Directive 95/45/EC purity criteria (E 174) and an SCCS opinion cited as the scientific basis. It is the only entry in the current Annex IV dataset carrying a populated product-type field, which is itself a useful reminder that most colorants are not restricted to specific product categories — only check for one when the record states it.

Why hair dyes are not governed by Annex IV

Article 14(1)(c)(i) of Regulation (EC) No 1223/2009 requires cosmetic products to contain only colorants listed in Annex IV, used according to the conditions set out there — but the regulation states explicitly that this point does not apply to hair colouring products. Article 19(1)(g) reflects the same split at the labelling stage: it carves out "colorants intended to colour the hair" from the CI-nomenclature and "may contain"/+/- rules that apply to other colorants. Hair-dye substances are instead addressed through Annex II (where individual hair-dye substances have been banned) and Annex III (which restricts specific hair-dye substances and sets their conditions of use), covered in a separate site article on Annex III hair-dye rules.

Checking a CI number before you trust it

Because the same CI number can appear on Annex II, Annex III or Annex IV depending on the substance and its use, the practical check is always: look up the CI number, confirm which annex the record sits on, and read every populated field on that record — not just the ones you expected to see. The site's search takes a CI number directly:

curl "https://cosingchecker.com/api/v1/entries/?q=77163"
curl "https://cosingchecker.com/api/v1/entries/?q=12075"
curl "https://cosingchecker.com/api/v1/entries/?annex=IV&per_page=100&page=1"

A record returned by that search is identity evidence — it tells you what a regulator has published about a CI-numbered substance and where. It is not a safe/unsafe verdict, and the absence of a field (no stated maximum concentration, no warning text) means the site has no data recorded there, not that no condition exists in the underlying law. Annex IV, like the other annexes, is amended regularly — CI 77820 entered the list in a 2026 regulation — so a formulation dependent on a specific entry should be checked against the current consolidated EUR-Lex text before use, not against a cached copy.

Sources

• Regulation (EC) No 1223/2009, Article 19 (ingredient labelling, CI nomenclature, "may contain"/+/- convention) — https://www.legislation.gov.uk/eur/2009/1223/article/19
• Regulation (EC) No 1223/2009, Article 14 (general restrictions on substances used as colorants, Annex IV scope and the hair-colouring-products carve-out) — https://www.legislation.gov.uk/eur/2009/1223/article/14
• Regulation (EC) No 1223/2009, consolidated text — https://eur-lex.europa.eu/legal-content/EN/TXT/HTML/?uri=CELEX:02009R1223-20250901
• Regulation (EC) No 1223/2009, Annex IV (list of colorants allowed in cosmetic products) — https://www.legislation.gov.uk/eur/2009/1223/annex/IV
• Colour Index — organisation and publishers (Society of Dyers and Colourists / AATCC) — https://colour-index.com/ci-organisation
• CosIng Checker — CI 12075 (Pigment Orange 5), Annex II entry 397 — https://cosingchecker.com/annex/ii/ii-397-colouring-agent-ci-12075-pigment-orange-5-and-its-lakes-pigments-and-salts/
• CosIng Checker — CI 77163 (bismuth chloride oxide), Annex IV entry 123 — https://cosingchecker.com/annex/iv/iv-123-ci-77163/
• CosIng Checker — CI 77891 (titanium dioxide), Annex IV entry 143 — https://cosingchecker.com/annex/iv/iv-143-titanium-dioxideci-77891/
• CosIng Checker — CI 77820 (silver), Annex IV entry 142 — https://cosingchecker.com/annex/iv/iv-142-ci-77820/
• CosIng Checker — Annex IV listing — https://cosingchecker.com/annex/IV/
• CosIng Checker — search — https://cosingchecker.com/search/
• CosIng Checker API — live stats — https://cosingchecker.com/api/v1/stats/