Soap has evolved over time, however, there are very few true soaps on the market today. Most body cleansers, liquid and solid, are actually synthetic detergent products. Detergent cleansers are popular because they make suds easily in water and don't form deposits. Some of these detergent products are actually marketed as "soap", but are not true soap according to the regulatory definition of the word.
To meet the definition of soap in the 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.
The FDA does not regulate what "natural" or "organic" means, so commercial soap manufacturers are free to use the term "natural" and "organic", even though they use synthetic ingredients.
True soap is made by combining oils (fats) and an alkali (salts), such as lye (sodium hydroxide), which is known as the saponification process. The lye reacts with the oils, turning what starts out as liquid into blocks of soap. When made properly, no lye remains in the finished product and glycerin, a natural humectant and moisturizer, is formed. Commercial soap manufacturers often remove the glycerin, replacing it with synthetic ingredients which tend to be drying, and the extracted glycerin is sold as a separate product.
Our handmade soaps are free of parabens, phthalates and sodium lauryl sulfate, with no synthetic detergents or harsh chemicals added, and the natural glycerin is not removed from our products.
When selecting soap, a good rule to follow is the fewer the ingredients listed, the better.