Novel peptides are described which comprise an amino acid motif selected from the group consisting of "PG", "GP", "PI" and "IG" and having up to 10 amino acids upstream and/or downstream of the amino acid motif, wherein "P" in the motif is proline or hydroxyproline and the peptide stimulates the development, maintenance and repair of bone, cartilage and associated connective tissue. The invention further relates to pharmaceutical compositions of these peptides, as well as therapeutic and prophylactic uses of such peptides.