Since 1947 Free Form Collagen Support Gluten, Wheat & Dairy Free Suitable For Vegetarians Kosher Parve Dietary SupplementL-Proline is an amino which serves as an important building block for collagen production. Collagen is the main structural protein found in connective tissue. L-Proline can serve to provide structural support. This product provides Free Form L-Proline to promote optimum absorption and assimilation.