To investigate the influence of high hydrostatic pressure on the reactions of glyoxal with lysine residues, the formation of end-products, namely N-epsilon-(carboxymethyl)lysine (CML) and 1,3-bis(5-amino-5-carboxypentyl)imidazolium salt (GOLD), was studied in model systems via LC-MS. Following a kinetic interpretation, reaction volumes were calculated. Corresponding values of +5.4 (CML) and +9.9 cmA(3)/mol (GOLD) indicate a suppressive effect of pressure on the formation of these glycation compounds. Above this, several other known end-products, namely N(6)-glycoloyllysine (GALA), N(6)-[2-[(5-amino-5-carboxypentyl)amino]-2-oxoethyl]lysine (GOLA), and reaction intermediates, were qualitatively monitored and proofed a similar behavior compared to the GOLD formation pathway. The reasons for the influence of pressure are discussed in the context of the reaction mechanism.