How to Take:
In general, L-carnitine will be absorbed faster and with higher peak plasma when ingested on an empty stomach, because it does not compete for absorption with other amino acids or peptides. When taken on an empty stomach, plasma levels of carnitine will remain elevated for 3-4 hours. If high blood concentrations throughout 24 hours are desired, carnitine should be taken multiple times per day in doses of 1-2 g, for example, first thing in the morning and around 2-3 hours after any meal or snack. It is not recommended late in the day due to its energizing effect. Do not take high doses too fast, as it may have a laxative effect.
Carnitine is especially useful to take right before exercise, for both resistance and endurance training. When taken with meals, it will achieve a lower but more prolonged elevated plasma level, about 7-8 hours, supporting at first the metabolism of the fat ingested with meals and subsequently that of the fat released from the adipose tissue.
It is important to keep in mind that when consuming an excessively high carbohydrate diet, fat release from the adipose tissue is impaired by high levels of insulin. In this case, fat cannot be transported into the mitochondria with the help of carnitine for it to be burned off, because it does not have a chance to first get in the bloodstream. The only benefit that carnitine can have in this case would be to support the transport of the fat absorbed from the meals into the mitochondria for burning. As a result, carnitine may reduce the chance of gaining body fat during a diet high in carbohydrates and fat, but fat loss is very unlikely in this metabolic situation. So, in order to maximize fat loss and benefit from L-carnitine supplementation, the amount of daily carbohydrate intake should be minimized and adjusted to match general activity levels and exercise type and duration.