A coenzyme is a cofactor. A loosely bound cofactor is a coenzyme and a tightly bound cofactor is a prosthetic group. Cofactors are non-protein “helper” molecules that can be classified as organic or non organic ( sometimes restricted to inorganic substances only). Organic molecules are either vitamins or made from vitamins like the vitamins B1 , B2, B3, B5, B6 and Biotin on https://naturesblendshop.com Inorganic cofactors are usually metal ions like Mg2+