Significance Proper functionality of the spermatozoa depends on the tight regulation of their redox status, at the same time these cells are very energy demanding, and in the energetic metabolism, principally in the electron transport chain (ETC) in the mitochondria, reactive oxygen species (ROS) are continuously produced, but also in the Krebs Cycle and during the beta-oxidation of fatty acids. Recent advances Additionally, in the glycolysis, elimination of phosphate groups from glyceraldehyde 3-phosphate and dihydroxyacetone phosphate originates as byproducts glyoxal (G) and methylglyoxal (MG); these products are 2oxoaldehydes. The presence of adjacent carbonyl groups make them strong electrophiles that react with nucleophiles of proteins, lipids and DNA, forming advanced glycation end products (AGEs). Critical Issues. This mechanism is behind subfertility in diabetic patients; in the animal breeding industry, commercial extenders for stallion semen contain a supraphysiological concentration of glucose that promotes methylglyoxal production, constituting a potential model of interest. Future directions. Increasing our knowledge on sperm metabolism and its interactions with redox regulation, may improve current sperm technologies in use, and shall provide new clues to for the understanding of infertility in males. Moreover, stallion spermatozoa due to its accessibility, intense metabolism, and suitability for proteomics/metabolomic studies may constitute a suitable model for studies of the regulation of metabolism and the interaction between metabolism and redox homeostasis.