A lotion is a low-viscosity topical preparation intended to smooth, moisturize and soften the skin. A body butter, in contrast, is thicker and has a consistency similar to the butter we eat. A body lotion/butter doesn't just add water back into your skin, it also traps in the water you already have to plump it up and protect it. Being your biggest organ in your body (yes, skin is the biggest human organ) it needs water to function properly. And the easiest way to provide water to your dry, tired skin is to generously apply body lotion or butter.