Synthetine is injectable L-carnitine is a trimethylated amino acid that plays essential roles in many areas of the body, including fatty acid translocation and muscle function. Carnitine is also acetylated into the ester Acetyl-L-carnitine (ALCAR) in the brain, liver, and kidney. ALCAR also plays a variety of roles in the body, including increasing acetylcholine production and stimulation of protein and membrane phospholipid synthesis.
Carnitine's primary job is in the regulation of cellular metabolism, and it closely interacts with coenzyme A in a variety of reactions. It is required for fatty acid oxidation, and this is the primary theoretical reason for improved exercise performance, as improved fatty acid oxidation will preserve muscle glycogen and improve ATP production.
Carnitine is a potent antioxidant (especially in combination with ALA) and there is evidence that it increases exercise performance for this reason. .