Glycation reactions, such as those seen in late diabetes, can be mimicked in purely chemical systems. The glycation is time-dependent, and in in vitro systems it can continue for days. Ascorbate seems to enhance the reactions. The reactions are associated with free-radical formation through transformation of an Amadori product to (deoxy-)glycoson, catalysed by heavy metals. Ascorbate enhances the reaction by a factor of 5-10 compared with in vitro systems without ascorbate. In vitro systems containing bovine serum albumin retard the formation of free-radicals, because of the formation of advanced glycation products.