Iron Oxides: Reading CI 77491, 77492, and 77499 on Labels

If you make mineral makeup, tinted moisturizers, or colored soap, you have run into those cryptic CI numbers on supplier spec sheets and wondered why colorants get a numeric code instead of just a name. Here is what they mean and how to handle them correctly on a filing.

What a CI number actually is

CI stands for Colour Index, an international classification system for dyes and pigments that predates modern cosmetic regulation by decades. It exists because a single pigment can be sold under many trade names across industries (textiles, paints, cosmetics), and the CI number pins down the exact chemical identity regardless of what the marketing label says. On a cosmetic ingredient list, colorants are typically identified by their CI number, sometimes alongside or instead of an INCI name.

Iron oxides are some of the most common colorants in cosmetics precisely because they are naturally derived, stable, and produce dependable earth tones without the regulatory complexity that surrounds some synthetic dyes.

The three iron oxide numbers you will see most

CI Number	Common name	Typical color	Typical use
CI 77491	Red iron oxide	Red to reddish-brown	Blush, lipstick, foundation, soap colorants
CI 77492	Yellow iron oxide	Yellow to golden	Foundation, concealer, soap colorants
CI 77499	Black iron oxide	Black to dark brown	Mascara, eyeliner, foundation, soap colorants

In practice, most "iron oxide" shades used in makeup and cold-process soap are blends of these three in different ratios to hit a target shade, similar to how a painter mixes primary colors. A supplier's "terracotta iron oxide" or "chocolate brown mica blend" is not itself a CI number, it is a proprietary blend name that needs to be broken down into its actual iron oxide components (and often other colorants or fillers) for a proper filing.

How they show up on a Cosmetic Notification Form

When you are filing in Canada, ingredients generally go by INCI name with a concentration or concentration range. Colorants including iron oxides are typically referenced by their CI number since that is how they are formally classified, and your supplier documentation should provide that number directly. Do not guess at a CI number from color alone. Confirm it from the supplier's certificate of analysis or safety data sheet, since two "red" pigments can be chemically different colorants entirely.

A few practical habits that keep this clean:

• Ask suppliers for CI numbers on every colorant, not just the trade name, at the time you first source the ingredient
• Keep the supplier's documentation on file, since it is your evidence for what you declared
• If a blend is proprietary, ask for the percentage breakdown of each colorant inside it, so you can carry the real concentration through to your finished product

Natural does not mean unlimited

Iron oxides are widely permitted, but "naturally derived" is not a blanket exemption from oversight. Cosmetic ingredient rules still apply to purity and permitted use categories, and the Cosmetic Ingredient Hotlist may carry specific restrictions or purity criteria for colorants depending on the market and product type. This is worth checking against the current Hotlist rather than assuming a mineral pigment gets a free pass just because it sounds inert.

Soap makers have a special wrinkle

If you are coloring true soap (an alkali salt of fatty acids sold only with a cleansing claim), the regulatory treatment of the finished bar may differ from a cosmetic. But the moment that same bar carries a cosmetic-type claim, moisturizing, exfoliating, anti-acne, it is treated as a cosmetic and the colorant declaration rules that apply to any cosmetic apply to it too. A lot of soap makers get tripped up here because they assume "it's just soap" protects them from ingredient declaration requirements once they start making skin-benefit claims on the label.

Making the paperwork match the pigment

Where this tends to go sideways is when a maker sources a pretty blended pigment under a fun trade name, uses it across five different product shades, and never actually documents the underlying CI numbers anywhere except a forgotten supplier email. When it comes time to file, that becomes a scramble. Cosmetic Comply matches colorant entries to their correct CI designation as part of screening your ingredient list, so that scramble happens once, carefully, rather than every time you launch a new shade.