Pro-Rite combines L-lysine and L-proline as free-form amino acids. L-lysine is an essential amino acid that’s a necessary building block for all protein in the body. L-proline is a major amino acid found in cartilage that’s important for maintaining healthy joint function and a healthy heart muscle. Without adequate protein, our body can’t build the structures it needs to make up our cells, tissues, and organs. It also can’t generate the substances needed for healthy function, muscle contraction, and immune support. L-lysine and L-proline are two key ingredients of collagen, an essential component for maintaining healthy arteries. Support your and joint health with one advanced formula.