Well if it's a body butter soap, it's not actually soap. It would be cosmetic.
How FDA defines "soap"
http://www.fda.gov/Cosmetics/GuidanceCo ... 074201.htmNot every product marketed as soap meets FDA's definition of the term. FDA interprets the term "soap" to apply only when --
* The bulk of the nonvolatile matter in the product consists of an alkali salt of fatty acids and the product's detergent properties are due to the alkali-fatty acid compounds, and
* The product is labeled, sold, and represented solely as soap [21 CFR 701.20].
So, if you are calling it body butter soap and it's intended use is to clean and help moisturize, then it's a cosmetic. The only other special thing that is required for you to do when making cosmetics is that you list all ingredients on your labels. So, if you were already listing all ingredients, then really there's nothing for you to change
Remember that drug and cosmetic are completely different things. A lot of us sell cosmetics (lip balms, lotions, bath salts, bath bombs, etc.). Drugs are something that you cannot sell without registering with the FDA.