Levocarnitine propionate or Propionyl L-carnitine (PLC) is the propionyl ester of L-carnitine. Propionyl-L-carnitine stimulates energy production in ischaemic muscles by increasing citric acid cycle flux and stimulating pyruvate dehydrogenase activity. The free radical scavenging activity of the drug may also be beneficial. Propionyl-L-carnitine improves coagulative fibrinolytic homeostasis in vasal endothelium and positively affects blood viscosity. It exhibits a high affinity for the muscle enzyme, carnitine acyl transferase, and as such readily converts into propionyl-CoA and free carnitine. Most studies of the therapeutic use of PLC are focused on the prevention and treatment of ischemic heart disease, congestive heart failure, hypertrophic heart disease, and peripheral arterial disease. PLC is marketed under the trade name Dromos®. It is indicated for patients with peripheral arterial occlusive disorders and for exercise intolerance enhancement in patients with chronic congestive heart failure. Dromos is marketed in Italy.

Tartaric acid is found in many plants such as grapes, tamarinds, pineapples, mulberries and so on. Wine lees (called mud in the US), the sediment collected during the fermentation of grapes, contains potassium bitartrate (potassium hydrogen tartrate) as its major component. L-(+)-tartaric acid is an enantiomer of tartaric acid. Twenty five years before the tetrahedral structure for carbon was proposed in 1874 to explain the optical activity and other properties of organic compounds, Louis Pasteur discovered the existence of enantiomerism in tartaric acid. L-(+)-tartaric acid is widely used in food and beverage as acidity regulator with E number E334.

L-carnitine (L-beta-hydroxy-gamma-N,N,N-trimethylaminobutyric acid) is conditionally necessary for mitochondrial transport and metabolism of long-chain fatty acids, and thus for myocardial energetic metabolism. D-carnitine is not biologically active and might interfere with proper utilization of the L isomer, and so there are claims that the racemic mixture (DL-carnitine) should be avoided. The pharmacological effects of carnitine are stereospecific: L-carnitine was effective in various animal and clinical studies, while D- and DL-carnitine was found to be ineffective or even toxic to some cells and tissues, such as muscle cells and the myocardium. DL-carnitine caused symptoms of myasthenia and cardiac arrhythmias, which disappeared after L-carnitine administration.