INS and hypogonadism: In conclusion, by comparing metabolic pathways recorded in those with IS and IR hypogonadism before and after testosterone restoration, it can be affirmed that testosterone deficiency (independent of the presence or absence of insulin) causes a decrease in lactate and acetyl-CoA, TCA cycle reduction, blockage of the production of acetyl-Carnitine and consequently of β-oxidation, and blockage of collagen synthesis and carnosine production.