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In the following excerpt adapted from an article featured on the Chemist's Corner, Tony O'Lenick looks to Perry Romanowski to illustrate how names are assigned to cosmetic raw materials for the benefit of novice formulators. The cosmetics industry does not use the International Union for Pure and Applied Chemistry (IUPAC) naming system. Instead, it follows its own system as laid out in the International Nomenclature of Cosmetic Ingredients (INCI) dictionary. This dictionary is recognized worldwide by the cosmetics R&D industry, and is produced by a cosmetic industry trade group known as the Personal Care Products Council (PCPC).
List of Ingredients
The first thing to know about cosmetic ingredients is the ingredient list. In the United States, every personal care and cosmetic product is supposed to have its ingredients listed. In the business, this is referred to as the list of ingredients (LOI). Any ingredient above 1% is required to be listed in order of concentration by weight. At 1% or below, the ingredients can be listed in any order. Typically, preservatives and dyes are listed at the end. To be proper, companies should follow the naming conventions as laid out in the INCI dictionary.
Cosmetic Ingredient Naming Conventions
While many chemical names in the INCI seem arbitrary, there are some standard rules. The following conventions will help the reader make heads or tails of the ingredients on most LOIs. While all the conventions are not listed here, the major ones are, in addition to examples.
When the PCPC first developed the INCI dictionary, originally called the CTFA Cosmetic Ingredient Dictionary, in 1973, many cosmetic ingredients already had names. These common names were incorporated into the dictionary even though they did not follow specific naming rules. Therefore, the term glycerin is used rather than the more accurate glycerol, and menthol rather than (1R, 2S, 5R)-2-isopropyl-5-methylcyclohexanol. Common names are also used for various natural ingredients like lanolin and beeswax.
Probably one of the most important basics to learn about naming cosmetic ingredients is the list of hydrocarbon stem names. This is a bit different than the IUPAC. For example, in the case of a 16-carbon alcohol, it is called cetyl alcohol instead of hexadecanol. For an 18-carbon acid, stearic acid is used instead of octadecanoic acid.