Nowadays more and more people are health conscious and interested in learning about the ingredients that they are using on their skin and hair. While cosmetic chemistry is broad and complex, in this article we will take a look at some common terms used in hair product formulation.
10 Common terms used in hair product formulation
1. Emulsion/ Emulsifier
An emulsion is a mixture of two or more liquids that are normally immiscible (tend to separate into 2 layers). For example: vinaigrette or mayonnaise. When the oil and water are shaken, the droplets of oils mixing in the water creates a cloudy mixture but eventually, the two layers separate. That’s where an emulsifier comes in handy. The role of the emulsifier is to keep the mixture uniform and prevent the separation into individual layers.
Examples of such emulsifiers in hair products are: ceteareth-25, PEG-40 Hydrogenated Castor Oil, cetearyl alcohol among many others.
Emollients have the ability to make the hair or skin soft and supple by creating a barrier that prevents moisture from evaporating too quickly.
Some examples of emollients are: cocoa butter, shea butter, certain oils like coconut oil, or fatty alcohols like cetyl alcohol.
Stabilizers maintain the function and activity of other ingredients present in the cosmetic formulation, like the pH value to check excessive acidity or alkalinity of the product. They assist the emulsifiers by preventing the emulsion from separating over time.
Examples: Glyceryl Stearate, Apricot butter …
Thickeners are added to enhance the stability and the overall performance of the cosmetic product. They give body to the product. As thickeners are derived from varied sources, they can be completely natural like waxes and also synthetic or semi-synthetic.
Examples: Olive butter, Guar gum, acrylates copolymer…
Also known as a dispersing agent, it improves the separation of particles in the emulsions and prevents settling or clumping. Dispersants consist normally of one or more surfactants.
Examples: Dimethylimidazolidinone rice starch, Propoxylated stearyl alcohol …
The word surfactant is short for ‘surface active ingredient’.
Surfactants are possibly one of the most common terms used in hair products formulation. When they are put into solutions, the molecules have a tendency to line up in a certain way depending on the solution composition, the concentration of the surfactant, and the temperature.
Surfactants have several uses with one of the most popular being as a detergent in products like shampoos for cleaning. The cleaning mechanism can be reviewed here. However, different surfactants have different structures with some being uncharged, others having a positive charge etc as shown in the image above. Choosing the appropriate surfactant will dictate its role in the formulation: as emulsifiers, foaming agents (create foam in the product), solubilizer (make product clear), and even as dispersants.
Examples: Sodium laureth sulfate, sodium cocoyl isethionate, decyl glucoside …
Quats are another way of referring to positively charged ingredients (quaternary ammonium compounds). These are mostly used in conditioning products since they deposit well on hair (which has a partial negative charge). Different quats have different feel and effects on hair. They can impart softness, antistatic properties, shine, detangling properties etc.
Some common ones used in conditioners are: Polyquaternium-4, Behentrimonium chloride, cetrimonium chloride …
Learn more about how conditioners deposit on hair here.
Humectants have the ability to retain or preserve moisture from hair or skin. Some compounds also have the ability to actively attract moisture. Humectants are also often used in hair care products to volumize the hair by attracting moisture which expands the hair shaft. With that being said, this might be a problem for those who suffer from frizz problems. Excessive amounts of those specific humectants can cause unwanted additional frizz.
Some examples of humectants include propylene glycol, glycerin, panthenol …
9. Fatty alcohol
Fatty alcohols are often confused as being similar to ethanol because of its name. Ethanol evaporates very quickly, and while it is useful in certain products like hair sprays, it can create a drying effect on hair. Fatty alcohols are in the alcohol family but are very different in properties due to their long chains of carbon. They are often used as emollients, emulsifiers, thickeners etc. Read here for a more detailed explanation of fatty alcohols.
Polymers are made from small identical units joined together chemically to form a larger structure (typically a chain-like structure). Polymers in the natural world have been around since the beginning of time. Starch, cellulose, and rubber all possess polymeric properties.
Polymers are present within many hair care products and are used to modify the appearance of hair, for example to make it straighter, shinier or to change its color among other things.
Examples of such polymers include silicones such as cyclopentasiloxane, Polyquaternium-10, Hydroxyethylcellulose, PEG-150 distearate …