CI numbers in makeup ingredients, explained

What a CI number is

The number comes from the Colour Index, a classification of dyes and pigments published by the Society of Dyers and Colourists and the American Association of Textile Chemists and Colorists. It lists each colourant under a generic name and a constitution number.¹

EU cosmetics law uses that numbering. An ingredient list must name colourants by their Colour Index number where one applies², and the EU's list of permitted colourants, Annex IV, records each one by its CI number, with its colour and any conditions of use.³ That is why an EU label can show CI 15850 where a chemist would write a long chemical name.

Only colourants in Annex IV may be used to colour a cosmetic, and only under the conditions written there.² An entry also covers the colourant's salts and lakes.³ A lake is a colour fixed onto a base so that it does not dissolve in water, which keeps it from bleeding, as in lipstick.⁴

Why they sit at the end of the list

EU rules let colourants be listed in any order after all the other ingredients², and US rules do the same for colour additives of any concentration.⁵ So the CI numbers cluster at the end, and their position is not a measure of amount: a colourant printed last is not necessarily a small part of the product.

In that example, CI 77891 is titanium dioxide, a white pigment that the EU ingredient database also lists as opacifying⁶, and CI 77491 and CI 77492 are the red and yellow iron oxides.³

"May contain" and "+/-" in a shade range

A foundation, lipstick or eyeshadow sold in many shades can print one list for the whole range. EU rules allow this for decorative products marketed in several colour shades: every colourant used across the range may be listed, provided the words "may contain" or the symbol "+/-" are added.² The CI numbers after that mark are the range's palette, not a list of what is in your shade.

US rules draw a finer line. In a branded shade line, colour additives found in every shade must be listed before "may contain", and only those that are not in every shade may follow it. A colour added to some batches only to match a shade can also be listed after "may contain".⁵

If you avoid a particular colourant, a "may contain" list cannot tell you whether your shade has it. Ask the brand about the shade you want.

Common CI numbers in makeup

The FDA's substance records match the synthetic colours to their CI numbers: CI 15850 and CI 15850:1 to D&C Red No. 6 and No. 7, CI 19140 to FD&C Yellow No. 5, and CI 42090 to FD&C Blue No. 1.^9101112 FD&C Yellow No. 5 is the certified form of tartrazine.⁴

Carmine comes from cochineal insects⁸, so CI 75470 in a "+/-" list is worth asking about if you avoid animal-derived ingredients.

On a US label

US packs name colour additives their own way. Synthetic colours carry a prefix (FD&C, D&C or External D&C), a colour and a number, such as FD&C Yellow No. 5, and may be listed by colour and number alone, as Yellow 5. Every batch of these colours must be certified by the FDA. Colours from mineral, plant or animal sources, such as iron oxides or carmine, are exempt from batch certification, but every colour additive still needs FDA approval for its use.⁴

The FDA tells manufacturers not to confuse certified colours with colours identified only by a CI number: a CI number does not indicate FDA certification.⁴ On a pack, a CI number is a name, not a certificate.

Permitted uses can differ by body area. In the US a colour additive may be used near the eyes only if its listing says so: FD&C Blue No. 1 and FD&C Yellow No. 5 are listed for eye area use, while D&C Red No. 6 and No. 7 are listed for cosmetics generally, which does not include the eye area.⁴⁷ In the EU, some Annex IV entries likewise limit a colourant to rinse-off products, or rule out eye products or products applied to mucous membranes.³

What to look for on the label

• At the end of the list: the CI numbers, in any order. Their position is not a measure of amount.²
• After "+/-" or "may contain": the colourants of the whole shade range, not necessarily of your shade.²
• "(nano)" after a name: the ingredient is present as a nanomaterial, which an EU list must state in brackets after its name.²
• CI 77891 or Titanium Dioxide: the same white pigment under two names. The EU lists it as CI 77891 among colourants and as Titanium Dioxide among UV filters, so the name depends on its job. See Titanium Dioxide.³⁶
• Mica: a silicate mineral that appears under its own name rather than a CI number, with colourant among the functions the EU ingredient database records for it.¹³

To see what each number on your own label is, paste the list into the ingredient checker, which matches CI numbers and US colour names to EU entries. For the order of the rest of a list, see the guide to ingredient list order, and for how label names work, what INCI names are.