Is Glycine Good For Building Muscle? Human Performance Hub Swanson Sports Supplements Propionyl L Carnitine with Glycine 60 Veg Caps : Target L Carnitine 500mg ml 20ml Peptide Revolution Glycine Propionyl L Carnitine HCI GPLC If you are like a lot of people, you may have never heard of carnitine but this important nutrient is critical for our body's ability to optimally burn fat required for energy.