Reflex Acetyl-L-Carnitine Description Acetyl-L-Carnitine is similar in form to the amino acid L-Carnitine & also has some similar functions, such as being involved in the metabolism of food into energy. It may boost the immune system, energy levels, stamina & production of ATP. It may also increase brain function alertness, elevated mood & focus as well as maintaining testosterone levels post workout. However, Acetyl-L-Carnitine is absorbed into the bloodstream more efficiently than L-Carnitine & more importantly, Acetyl-L-Carnitine passes more effectively through cell membranes & is utilized more efficiently in the mitochondria of the cell.