Part of what I enjoy about making soap is the simple natural chemistry of it all. To make soap you add lye (originally the lye was derived from wood ash from a fire), water and fat together in very precise amounts which combines to create a new molecule we call soap and another called glycerine. The new soap molecule helps attract dirt and with the addition of running water (your shower) will wash the dirt off the body. Glycerine is another byproduct that acts as a humectant (ie. retains moisture on the skin). Many commercial soap companies extract the glycerine from their soap and either put some back in the soap or sell it for use in other products for many different industries. Hand made soap retains all of the glycerine produced plus most handmade soap makers, including myself, add a little extra fat in their soap that help replenish any natural oils lost in the washing process.
Detergents are a different kind of product all together. Some commercial mass produced soaps would be considered detergents. If you want to know the difference just look at the labels of the products you buy (if they list them). To make a long story short detergents were created in 1916 as a result of the lack of fats for soap making and the need for a cleaning substance that would work better for washing in water that was mineral rich. So, without getting into too much detail, just know that there is a difference between soap and detergents and your skin can react differently to both. If you are interested in the history of soap there is lots of information on the internet. But I found this very simple and easy to read article on the history of soap from the cleaning institute.org link below:
My brief synopsis is a very simplified explanation of the soap making process but gives you a good idea of what its all about. My hope in this page about soap is that you simply understand what it is you are using to clean yourself and your family and realize the quality of handmade soap for your skin.