Yes. All true soap is made with lye. Most big-brand, store bought soap isn't true soap, but rather a chemical surfactant with additives. True soap is the final product resulting from a chemical reaction called saponification. Saponification occurs when a lye solution (sodium hydroxide for bar soap, or potassium hydroxide for liquid soap) is mixed with triglycerides (fat or oil). Once saponification is complete, the lye no longer remains and you're left with natural glycerin and soap.