In a previous pilot study in healthy subjects with decreased insulin sensitivity, the investigators found that 6-month treatment with Acetyl-L-Carnitine - an ester of l-carnitine - improved the glucose disposal rate, taken as a marker of insulin sensitivity. Amelioration of insulin sensitivity was associated with a significant and clinically relevant reduction in systolic blood pressure without appreciable changes in diastolic blood pressure. Whether blood pressure reduction reflected the amelioration of insulin sensitivity or, rather, a direct, specific effect of Acetyl-L-Carnitine is still unknown.The antihypertensive effect ensued progressively and slowly waned after treatment withdrawal as documented by a slow and progressive increase in blood pressure levels toward baseline levels over the recovery period. This finding provided convincing evidence that blood pressure reduction throughout the observation period was not explained by a "trial effect", but reflected a true treatment effect. Blood pressure was a secondary efficacy variable of the study and mechanisms underlying the antihypertensive effect of Acetyl-L-Carnitine (such as reduced peripheral resistances, decreased cardiac output, increased artery compliance and/or enhanced sodium excretion), in this population were not assessed.