 A set of vitamers with related biological activity are grouped together by a general name, or "generic descriptor", that refers to similar compounds with the same vitamin function.For example, "vitamin A" is the generic descriptor for the class of vitamin A vitamers which include retinol, retinal, retinoic acid, and provitamin carotenoids such as beta-carotene among others.Vitamers often have subtly different properties from their primary, or most common form.