As we have already seen, carnitine may have a positive influence on aerobic endurance performance. In view of its lipid-carrying capacity in muscle, and thus its ability to facilitate fat oxidation, this amino acid may also have a slimming function. More specifically, the theory is that a higher intake of carnitine equates to greater fat oxidation and, consequently, easier disposal of excess fat deposits. Research, however, has shown conflicting results, so that the theoretical assumptions are not always confirmed: Villani (2000) does not detect any acceleration of fat loss in some overweight women; Schaffhauser (2000) observes different results in some obese people. Kajac (2001) noted that carnitine works better in people with high fat mass percentages than in those with lower percentages. It is likely that carnitine only works where the hormonal situation is conducive to slimming: if the balance in the leptin-grelin axis is too unbalanced in favour of the latter, if the secretion of thyroid hormones is too low, if there is insulin resistance or, in any case, if there is some biological condition whereby lipid disposal is hindered, increasing carnitine intake will not help. In fact, carnitine has no direct influence on cells: it does not promote the emptying of adipocytes, just as it does not directly promote lipid β-oxidation. It merely transports fats. Therefore, in the absence of a willingness on the part of the adipocytes to release the fats contained therein into the blood stream and on the part of the peripheral cells to pick them up and oxidise them, an increase in carnitine intake will in no way benefit the slimming process. Added to these limitations are the negative effects already seen in the section on performance-enhancing supplementation products. Finally, as far as optimal dosages for slimming are concerned, research in which carnitine supplementation has been successful suggests taking 2 to 4g/day, divided into two daily intakes (remember that carnitine supplements are commercially available in tablet and soluble powder form). If your training regime includes sessions devoted to endurance, especially general (aerobic) training, it is advisable to take the product 30 to 60 minutes before the session.