UC-II 40 mg 120 CapsulesDietary Supplement Undenatured Collagen Joint Comfort! Cartilage is the connective tissue that covers the ends of your bones to form a smooth, shock absorbing surface for your joints. Years of stress from our own immune system can wear away cartilage and limit joint flexibility. UC II, or undenatured type II collagen, when taken orally, helps support a healthy inflammatory response, immune function, and increased joint flexibility and mobility.