Soap is a kind of detergent which helps in removing greasy dirt. The three main ingredients used in soap are fat (or oil), lye and water
Warm fats(palm oil,olive oil,coconut oil according to our taste) which reacts with lye(sodium hydroxide NaOH) and then fatty acids are added to make it true commercial product.
Lye, distilled water & fat or oil. Whatever you do stay away from commercial soap; it is stripped of glycerin which occurs naturally in col process soap and has so many ingredients that consumers have never even heard of. It is very drying to the skin.