Acetylcarnitine (ALCAR)

Acetyl-L-carnitine or ALCAR, is an acetylated form of L-carnitine. It is naturally produced by the body, although it is often taken as a dietary supplement. Acetylcarnitine is broken down in the blood by plasma esterases to carnitine which is used by the body to transport fatty acids into the mitochondria for breakdown. ALCAR is an acetylated derivative of L-carnitine. During strenuous exercise, a large portion of L-carnitine and unused acetyl-CoA are converted to ALCAR and CoA inside mitochondria by carnitine O-acetyltransferase. The ALCAR is transported outside the mitochondria where it converts back to the two constituents. The L-carnitine is cycled back into the mitochondria with acyl groups to facilitate fatty acid utilization, but excess acetyl-CoA may block it. Excess acetyl-CoA causes more carbohydrates to be used for energy at the expense of fatty acids. This occurs by different mechanisms inside and outside the mitochondria.