What is soap made of?
august.build
august.build
The soap itself is the bulk emulsifying agent, which in particular is the reaction product after treating rendered oils with an aggressive alkaline lye solution.
The strong lye seeks out weak points among the carbon chains of the mostly-saturated oil molecules, then reacts in those spots to end up with sodium salts of fatty acids, which imparts the property of water solubility to the former oil molecules. The resulting purified soap then can be conveniently used to remove plain oil & grease of many kinds by being mixed with the oil & grease to make the entire mixture soluble enough to wash away with water.
Therefore soap is not one particular chemical, but a particular class of chemicals. Traditionally made by treating rendered vegetable or animal fats. Caustic soda lye reacts with rendered oil to form sodium salts, caustic potash lye would yield the corresponding potassium salts.
Plus there are a number of other emulsifiers which can remove oil & grease and are chemically distinct from soaps. One of the major alternative classes is detergents. These are not soap at all even though they clean & foam.
Anyway on the list presented these are the items that stand out as actual soaps. Others I would put into the category of byproducts or additives:
Sodium Laurate
Sodium Stearate
Sodium Oleate
Sodium Palmate
Sodium Tallowate
Sodium Palm Kernalate
Sodium Cocoate
Notice these are all sodium salts of fatty acids derived from natural oils. If the pH is neutral enough no other additives or buffers may be necessary, that would be just plain soap.
But the raw oils as well as the acid forms of salts like this (a few can also be found on the list) can also be quite mild bulk commodities and certain amounts have often remained in, or found their way into, different formulations for different reasons.
A soap product itself may or may not be an irritant to different people at different times, but even if completely innocuous as a chemical, I would think it would be possible to overuse it habitually enough to compromise a protective layer of natural oils to a point which allows irritation to occur from exposure to completely unrelated agonists which otherwise do not act as triggers at all.