The term ‘water based cream’ is a marketing strategy to make you believe that that cream is lighter to use. Every cream is an emulsion of an oil (lipid) phase and a water (aqueous) phase. You can pour the water into the oil or pour the oil into the water…the formula remains the same, the consistency changes a wee bit. In simpler terms, the oil phase may consist of 40% and the water phase 60%. You can pour one into the other but the amount of both phases is constant so the effect on the skin is the same.
A butter is purely the lipid phase with no water added. It consists of fats…butters, oils and sometimes bees wax for added protection for the skin.
So a water based cream simply means that it is exactly the same as an oil based cream, except that in this case the oil phase is poured into the water phase.