What it is
In the register’s words: “CI 42090 is classed chemically as a triphenylmethane colour.”
- EU register name (INCI)
- CI 42090
- CAS number
- 2650-18-2/ 37307-56-5/ 3844-45-9
- EC number
- -/ -/ 223-339-8
US labels use the US name where it differs from the EU one, so a label may say Blue 1 (CI 42090) where the register says CI 42090. Both are the same ingredient.
What the register lists it for
These are the uses the European Commission’s CosIng register lists for Blue 1 (CI 42090) in any cosmetic, hair roles first. They say why a maker might add it, not what it does in one formula, and they aren’t a safety rating.
- Hair dyeing
-
Colors hair. In these wash-day products, an ingredient with this role is usually there for a listed use of its own, not to dye your hair.
Register definition: “Imparting color to hair. Hair dyeing preparations may be temporary, semi-permanent, permanent, depending on the length of time the colorant remains on the hair.”
- Colorant
-
Colors the product itself, or the hair or skin. EU law allows only the colorants on its own list.
Register definition: “Exclusively or mainly intended to colour the cosmetic product, the body as a whole or certain parts thereof, by absorption or reflection of visible light; (precursors of oxidative hair colorants shall be deemed colorants). All authorised colorants are substances in the positive list of Annex IV to the Cosmetics Regulation 1223/2009.”
Where it sits on each label
US labels list ingredients from most to least, except that those at 1% or less may follow in any order. A name near the top is a large part of the formula. A label doesn’t mark where the 1% point falls, so further down, the order says little about how much is in it. Colors are a further exception: the FDA lets a color additive at any concentration be listed in any order after the other ingredients, so where Blue 1 (CI 42090) sits says nothing about how much is in it.
- Rinse-out conditioners 1 label First five names: 0 of 1 Rinse-out conditioners without it
- Leave-in conditioners 1 label First five names: 0 of 1 Leave-in conditioners without it
Every label, product by product (2)
- Aunt Jackie's In Control Moisturizing Softening Conditioner Rinse-out conditioner 39th of 39 names
- Aunt Jackie's Quench! Moisture Intensive Leave-In Conditioner Leave-in conditioner 31st of 31 names
Each line runs from the first name on a label to the last; a dot is where this ingredient sits. Makers change formulas now and then; if the list on your bottle differs, go by your bottle.
Your next step
Other hair dyeing ingredients on these labels
- CI 19140 (Yellow 5) 4 labels
Updated · The name, numbers and uses come from the European Commission’s CosIng entry (CC BY 4.0); we write the uses in US spelling and put the hair ones first. The labels are each maker’s own. The order rule is the FDA’s Cosmetics Labeling Guide. All our sources are on the Sources page.