You can add glycerin and/or panthenol after dilution for their humectant properties. Remember that soap is a wash off product and really does not moisturize but it can be harsh in that it can strip your skin its natural oils or it can be gentle in formulations that do not strip the skin - and everywhere in between. You can formulate to have less cleansing qualities (less coconut or babassu oil for example) to create a more gentle soap.