Yes, we use caustic sodium hydroxide in our neem soaps – but the truth of the matter is that ALL soap makers use lye. A cleaning product made without lye is actually a detergent, made with surfactants like alkylbenzenesulfonates.
The lye, however, goes through a process called saponification, in which the strong alkaline reacts with triglycerides in fat to create a product similar to those used in ancient Rome. After saponification, there is no remaining lye because it has been chemically altered – albeit in a natural process.
And while we clearly identify sodium hydroxide as an ingredient, many companies chose to pretend that their soap does not contain lye. You’ll see ingredients like saponified oils, sodium cocoate, palmate or olivate. All use the same saponification process that turns lye and oil into soap, whether the ingredient is listed on the label or not. (Learn more at https://en.wikipedia.org/wiki/Soap.)
Over the centuries, soap makers have developed very clear charts that identify how much lye and oil must be mixed together to complete the process and end up with a soap that doesn’t burn skin. We take that chart one step further and add extra neem oil to “superfat” our soap. That means the neem oil still exists in its original form and makes our soaps extra rich and soothing for dry itchy skin.
Interestingly enough, the process of turning fat and an alkaline substance into a cleanser goes back nearly as far as the use of neem to treat skin disorders. The first records date back to about 2800 BC in ancient Babylon and a formula was documented on a clay table about 2200 BC. The ruins at Pompeii include a soap factory, and ancient Egyptians wrote recipes for soap on papyrus.