Dietary Supplement. 275 MG L-Proline / 275 MG L-Lysine. L-Lysine is one of 9 essential amino acids that cannot be made in the body. It is the basic raw material for carnitine synthesis. L-Proline can be made in the body but low protein/vegetarian diets may not always promote optimal L-Proline production. L-Lysine and L-Proline amino acids are the precursors of hydroxylysine (HL) and hydroxyproline (HP) two constituents of collagen. Collagen is an essential component of arterial linings. Vitamin C a strong antioxidant is also essential for the production of collagen. Hawthorn berry and grape seed extract are potent natural antioxidants due to their high levels of proanthocyanidin. These proanthocyanidin-esters are excellent free radical scavengers.