In the first part of this cosmetic ingredient naming series we covered how the ingredients got their official names and some of the regulatory framework in the US that set it up. In this next section, we will cover what the ingredient names mean and how they relate to the chemistry of the ingredient. By knowing the structure and chemistry of ingredients you will be in better shape to figure out what the ingredient might do in your formula.
Common Trivial Names
Since the INCI naming system was only created in the 1970’s there were a number of compounds that already had existing names. So, rather than change what people already called these ingredients the system incorporated common names. Ingredients like Glycerin and Menthol are examples. Also, the INCI system used names for things that were already listed in sources like U.S. Pharmacopoeia (USP), National Formulary (NF), the Food Chemicals Codex (FCC), Merck Index, and more. Sometimes these names reflect the structure of the materials but usually they don’t. To learn what the material is you have to look it up.
A large portion of cosmetic ingredients are hydrocarbons. You may have first learned about naming hydrocarbons in Organic Chemistry. This is the IUPAC system and it allows you to figure out the chemical structure of any compound by its name. While this naming system is too complex for the cosmetic industry the INCI naming system did incorporate the old semi-systematic list of stem names to designate hydrocarbons.
On the right side of this post you’ll see a list of stem names used in the INCI system.
So, if an ingredient has 12 carbons you would use the terms “Lauryl” for the alcohol version and “Lauric” for the acid version. A 16 carbon ingredient is Palmitic for the acid and Cetyl for the alcohol It’s helpful for a formulator to memorize this list.
Some ingredients come directly from natural materials like coconut oil, palm oil or sunflower oil. While these ingredients have a primary component they usually a blend of multiple fatty acids. Rather than spell out every ingredient in the material they are simply named using the starting material name. So there is coconut acid, soy acid, or tallow alcohol. And derivatives of these materials also maintain the source stem name. Ammonium Palm Kernal Sulfate for a surfactant made from Palm Kernal oil for example. To be a great formulator you’ll want to learn the fatty acid distribution of different types of starting raw materials.
Hydrocarbons that contain nitrogen atoms are referred to as amides. Therefore, lauramide is used to describe a 12-carbon molecule (lauryl) that has an NH2 group on its end. If the nitrogen has other hydrocarbons attached, those are also named. So, lauramide DEA would be that same 12-carbon molecule attached to a nitrogen, which also has ethyl groups attached to it. When these nitrogen-containing compounds are turned into salts, the suffix -monium is added. So, a 16-carbon attached to a nitrogen with three methyl groups is cetrimonium chloride
A number of materials in the cosmetic industry are those that contain silicone. For these ingredients the phrase ‘-methicone’ is typically used. Common ingredients include Dimethicone, Cyclomethicone, and Phenyl trimethicone. The term ‘-silane’ is also used for materials that have silicone in them that is bonded to another silicone atom rather than an oxygen atom. There are some silicone polymers that are difficult to name using typical silicone terms so these ingredients are simply called Polysilicone with a number after it denoting the order in which it was registered in the INCI dictionary.
Speaking of polymers, there are a number of materials used in cosmetics that are polymers. Most of these are named following their common usage. This is typically a name that covers the starting monomers and includes ingredients like Polyethylene Glycol or Polyvinyl Alcohol. When a blend of monomers are used the term Copolymer is used and the names of the starting monomers are listed in alphabetical order. Acrylates/Acrylamide Copolymer is an example.
When there are four or more monomers the INCI system allows for using a shortened term like Polyquaternium or Polyester with an arbitrary number following. A common hair conditioner is called Polyquaternium 10.
To understand these ingredients and their effect on a formula you just have to look up the structure.
These days a lot of plant materials are being used in cosmetic formulation. There has been some confusion about how these should be named. According to the INCI conventions botanicals are considered ingredients have not undergone chemical modification and include extracts, juices, waters, distillates, powders, oils, waxes, saps, tars, gums, unsaponifiables, and resins. The naming of these ingredients is based on the Linnean classification system using Latin names. So, you get names like Sunflower seed oil and Foeniculum Vulgare Fruit Extract. It can get a bit more complicated based on whether the ingredient is a blend of botanicals or which part of the plant it comes from. Also, when using botanicals you typically will have to list the solvent the ingredient is delivered to you in.
The final topic we’ll cover are abbreviations. In cosmetic ingredient names you often find three letter abbreviations to replace much longer words. DEA replaces Diethanolamine. PEG replaces Polyethylene glycol. AMP means Aminomethylpropanol. The first section of the INCI dictionary lists all of the acronyms that are used. In this link you can find a description of ingredient naming from the PCPC which lists all these acronyms and more.
Knowing the names of raw materials you use for formulating cosmetics will make you a smarter, more versatile cosmetic formulator. Hopefully, this series has given you a glimpse at what they are, how they are named and it will inspire you to learn the system in even more depth.
If you could get to the point where you have a good idea of what an ingredient is from either its INCI name or its trade name, you will be well on your way to becoming a complete cosmetic chemist.
Are you looking to learn how to become a cosmetic formulator? You would benefit from taking our course Practical Cosmetic Formulating.