They should make this a sticky because the newbies always ask this question. I'm a pharmacist in PA. I'm going to copy and paste a post I wrote in another subforum:
Go to the skin care aisle of most any pharmacy and you'll find a small(usually 6oz) bottle labled Glycerine, USP(Some pharmacies don't carry outright , but will special order for you). The label may have it listed as CVS Glycerine, USP or Rite Aid Glycerine, USP or Humco Glycerine, USP or Family Pharmacy Glycerine, USP etc.. you get my point. Whatever it's labeled, it's Glycerine, USP 99.5% anhydrous(meaning 0.5% water). It will cost anywhere from $3 to $6 for 6oz.(CHEAP) This is vegetable glycerine, absolutely, positively, no doubt. How do I know this? I'm a pharmacist. All OTCglycerine,USP is made by 1 single manufacturer, HUMCO. It is then contract packaged into the different pharmacy labeled bottles. I've personally called HUMCO and spoke with their QA(quality assurance) person. He assured me that HUMCO's Glycerine is in fact Vegetable source Glycerine. The reason it's labeled Glycerine and not Vegetable Glycerine is because #1 it is listed in the USP as Glycerine, USP and therefore(in order to keep the USP certification) must be labeled as it's listed in the USP. #2 it would cause confusion as Glycerine is Glycerine(regardless of the source - chemically 1,2,3-propane triol also sometimes referred to as Glycerol), to add the moniker VEGETABLE, makes it sound like it's two different and distinct products, it isn't. Also, USP grade Glycerine is the purest you can get. Food Grade "vegetable Glycerine" you get in health food store saying 99.9% is BS. Since they do not have to meet any standard(such as USP standards) they could say anything, they could say 10000% pure. If you get USP grade, you know you are getting exactly what is labeled(within allowable USP limits) and it is made to most stringent requirements available in the US. (i.e. USP stands for United States Pharmacopeia- drugs have meet higher standards then foods do). Kashrut(kosher) laws are Jewish religious dietary laws having to do with the preparation of food products and really have nothing to do with the labeled purity of the product. Also, Kashrut(kosher) laws are jurisdictional(handled differently in different places). In some cases a rabbi must come to the manufacturer and verify processes and equipment conform to kosher law and in some places it's enough that the manufacturer says or thinks he is conforming to the kosher laws. In any case USP and Kosher are 2 different things. There is no such listing in the USP for "Kosher Glycerine". To the people who are feeling naseous using pharmacy bought Glycerine, USP, it may be a placebo effect(thinking your not using the real VG) or you may have a sensitivity to Glycerine(unlikely). But it is not because the Pharmacy bought Glycerine,USP is inferior or NOT Vegetable Glycerine.
------Yeah! What he said.