Swanson AjiPure L-Proline is a uniquely effective amino acid for health, thanks to its involvement in the many processes that produce and maintain connective tissues. Produced through fermentation using raw ingredients of non-animal origin, AjiPure amino acids are 99 to 100% pure. Impurities in other brands can be six times higher! AjiPure amino acids stand for purity, efficacy and safety. Ajinomoto is the leading supplier of amino acids for medicinal use, so you can be sure to trust the best.