Background
Per- and polyfluoroalkyl substances (PFAS) are a large family of chemicals in which most of the hydrogen atoms are replaced by fluorine. Currently, there are more than 12,000 different PFAS identified by the US Environmental Protection Agency (EPA). However, only a few hundred of those identified PFAS have been used commercially including multiple intentional uses in cosmetics. Due to the strength and stability of the carbon-fluorine bond, PFAS tends to be very stable and chemically inert. This makes them both very useful in multiple applications and very persistent in the environment, hence their label as forever chemicals. Depending on the length of the carbon chain, they may also be very persistent in the human body once they have been ingested. Ways of ingesting PFAS include as contaminants in food, drinking water or house dust, or inhalation through the air.
Use in Cosmetics
PFAS have been used in the formulation of cosmetics and other personal care products to perform a variety of functions. Some of these functions include acting as emulsifiers or lubricants and to control product consistency and texture. They are also used to make cosmetic products more durable and more resistant to water, weather, sweat and tears. Additionally, they are used to both add a shine to the skin and aid in the penetration of the surface of the skin. Finally, they are used in hair conditioners, to assist in combing wet hair and making them resistant to oils.
Detection in Cosmetics
There are two main classes of PFAS: fluoropolymers (those with very large molecules) and non-fluoropolymers (those with relatively small molecules). Fluoropolymers account for the bulk of industrial production, while non-fluoropolymers make up the majority of individual PFAS in the EPA’s database. Basic fluoropolymers such as polytetrafluoroethylene (PTFE) tend to be completely inert and non-toxic. However, non-fluoropolymers tend to display a wide range of chemical reactivity and potential toxicity. Fluoropolymers like PTFE have been widely used in cosmetics, even being the most common ingredient found in most cosmetics. Current testing methods do not appear to be capable of identifying fluoropolymers necessarily, but testing can identify a short list. This list of targeted non-polymeric PFAS measures what is known as Total Organic Fluorine (TOF) contained within the chemicals. A high TOF content in a cosmetic may not be so much of a cause for concern from a toxicity perspective. Currently, however, there is no easy way to determine if that is the case.
