L-proline (not to be confused with Prolene) is a nonessential amino acid that is used in the production of collagen in the human body. L-proline amino acid makes up about 15% of collagen in the body. L-proline amino acid works to protect and support the skin and fortify the joints.* It contributes to cardiovascular and heart health.* It also promotes a healthy gut and supports the digestive system.** These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease.