You are not alone if you have heard the term ‘true soap’ and been confused by what it means. Soap is soap, right? Not really. It all comes down to FDA regulations and the composition of the “soap”.
The FDA makes a distinction between a traditional soap and synthetic detergents. A traditional soap is made by combining fats and oils (vegetable, animal or mineral) with lye. The chemical reaction, called saponification, that occurs when the lye is added to those oils produces soap.
While most of the products on the market today are called ‘soap’ they are actually made with synthetic detergents and do not meet the FDA regulatory definition of a soap.
So what is the FDA definition of a soap? According to the FDA Frequently Asked Questions
To meet the definition of soap in FDA’s regulations, a product has to meet three conditions:
What it’s made of: To be regulated as “soap,” the product must be composed mainly of the “alkali salts of fatty acids,” that is, the material you get when you combine fats or oils with an alkali, such as lye.
What ingredients cause its cleaning action: To be regulated as “soap,” those “alkali salts of fatty acids” must be the only material that results in the product’s cleaning action. If the product contains synthetic detergents, it’s a cosmetic, not a soap. You still can use the word “soap” on the label.
How it’s intended to be used: To be regulated as soap, it must be labeled and marketed only for use as soap. If it is intended for purposes such as moisturizing the skin, making the user smell nice, or deodorizing the user’s body, it’s a cosmetic. Or, if the product is intended to treat or prevent disease, such as by killing germs, or treating skin conditions, such as acne or eczema, it’s a drug. You still can use the word “soap” on the label.
Most of the soaps made by handcrafters are true soaps (the notable exception is melt and pour). As a consumer, it’s all about reading the label. True soap labels will list water, lye (sodium hydroxide or potasium hydroxide), common names of oils and fats (e.x. shea butter, olive fruit oil, coconut oil), and possibly fragrance or essential oil, and colors (e.x. mica, titanium dioxide). Other ingredients may indicate the product contains synthetic detergents or drug additives (you will have to research them to see what they are) and therefore is not classified as a true soap.