OK lets get into the law, "By law for an oil is to be classified as synthetic it must be made so every single molecule MUST be the same, all the properties of the substance must be the same, and is composed of one or two atoms. The manufacturer doesn't have to tell you what that molecule is, it could be made from cooking oil, or candle wax, and they can legally call it synthetic, as long as every molecule is the same. I like to know what im dumping in my engine, I want the best, I use "AMSOIL"