The Royal Glucosamine D contains both glucosamine and calcium to strengthen the bones and joints. The slogan of this product, written on the bottle is: Normal walking today. Glucosamine is a compound found naturally in the body : made from glucose and amino acid glutamine. Glucosamine is needed in the formation and repair of cartilage and other body tissues. Production of glucosamine slows down with age. Since the body's natural glucosamine is used to make and repair joint cartilage taking glucosamine as a nutritional supplement helps repair damaged cartilage. The body needs calcium to maintain strong bones - Almost all calcium is stored in bones and teeth, and it supports their structure and hardness.