Human PTH-(1-31) is the 1-31 fragment of human PTH. Human PTH-(1-31) stimulates the release of cAMP and also is a weaker stimulator of the 25-hydroxyvitamin D-1α-hydroxylase. Human PTH-(1-31) induces bone formation without inducing bone resorption. Human PTH-(1-31) has the potential for the research of osteoporosis.