What is Soap?
Soap can be many things depending on who you ask. There is bar soap, liquid soap, body soap, dish soap, true soap and more! In this article, we will be diving into definitions and eliminating the confusion!
The regulations surrounding soap pertain mostly to how they are marketed and labeled. The claims that the company is making define what the product is and how it is regulated more so than the ingredients used. For example, if a product is marketed to make you smell nice, like a cologne or perfume, then they are considered a cosmetic. If the product claims it can treat or cure any type of ailment then it becomes a drug. Some products can even be both! This is a "cosmeceutical" and all regulations for both cosmetics and drugs apply.
The FDA defines these as follows:
Cosmetic: Articles intended to be rubbed, poured, sprinkled, or sprayed on, introduced into, or otherwise applied to the human body...for cleansing, beautifying, promoting attractiveness, or altering the appearance [FD&C Act, sec. 201(i)].
Drug: articles intended for use in the diagnosis, cure, mitigation, treatment, or prevention of disease" and "articles (other than food) intended to affect the structure or any function of the body of man or other animals" [FD&C Act, sec. 201(g)(1)].
Soap: the bulk of the nonvolatile matter in the product consists of an alkali salt of fatty acids and the product's detergent properties are due to the alkali-fatty acid compounds, and the product is labeled, sold, and represented solely as soap [21 CFR 701.20].
Now you may have more questions than when we started, but let's clarify some things! According to the FDA: If a product intended to cleanse the human body but does not meet all the criteria for soap it is either a cosmetic or a drug.
If a product
consists of detergents, or primarily of alkali salts of fatty acids, and
is intended not only for cleansing but also for other cosmetic uses, it is regulated as a cosmetic.
Examples of cosmetic uses include making the user more attractive, by acting as a deodorant, imparting fragrance to the user, or moisturizing the skin.
If a product
consists of detergents, or primarily of alkali salts of fatty acids, and
is intended not only for cleansing but also to cure, treat, or prevent disease, or to affect the structure or any function of the human body, it is regulated as a drug, or possibly both a drug and a cosmetic.
Examples include antibacterial cleansers and cleansers that are also intended to treat acne.
If a product
is intended solely for cleansing the human body,
has the characteristics consumers generally associate with soap, and
does not consist primarily of alkali salts of fatty acids, it may be identified in labeling as soap, but it is regulated as a cosmetic
Aside from the claims about what a product does, the recurring detail is the "primarily of alkali salts of fatty acids". What are alkali salts and fatty acids?
Alkali Salts: Salts that are the product of incomplete neutralization of a strong base and a weak acid.
Fatty Acids: A building block of fats. For my chemistry fans: A carboxylic acid consisting of a hydrocarbon chain and a terminal carboxyl group, especially any of those occurring as esters in fats and oils.
In soap making, the staple ingredients are fats/oils (fatty acids themselves) and sodium hydroxide (strong base). When these are combined, the mixture goes through a process called saponification. Saponification is a reaction in which free hydroxide breaks the bonds of ester between triglyceride fatty acids and glycerol, resulting in free fatty acids and glycerol.
I hope this helped clear up what soap really is. I know some of the chemistry can make things even more confusing, if you have any questions please reach out through the "Contact Us" link at the top of the page. I will respond directly and use your questions to create better articles!