The present invention provides novel short-chain peptides, which primarily act as parathyroid hormone (PTH/PTH-1) receptor agonist. These short-chain peptides exhibit increased stability to proteolytic cleavage. Most of short-chain peptides were found to be stable in rat plasma up to 24 hours (in vitro), showed increased stability against GIT enzymes such as pepsin and acidic stomach pH and also against liver microsomes (in vitro). Due to increased metabolic stability, other than parenteral route of administration, some of the short-chain peptides can also be delivered by oral routes of administration, for the treatment/prevention of hypoparathyroidism and diseases characterized by bone mass reduction, such as osteoporosis, postmenopausal osteoporosis and for stimulating bone repair. A-Z1-Z2-Z3-Z4-Z5-Z6-Z7-Z8-Z9-Z10-Z11-Z12-Z13-Z14-Z15-B