Collagen MD Products are all-natural, do not contain sugar and are gluten free. They work to relieve pain and help make skin look brighter and fuller. Collagen MD Advanced Connective Tissue Formula works to regenerate cells, helping to promote better looking skin. Collagen II Joint Formula is an amazing product that helps to reduce stiffness in joints. Collagen is naturally produced in your body, but over time your body makes less of it.