Why it is used in post menopausal osteoporosis?

PTH analogue would promote bone resorption,then why it is used in post menopausal osteoporosis?What is the mechanism of action?

When under continuous exposure to PTH (e.g., hyperparathyroidism), bone undergoes resorption more than formation, while intermittent exposure to low-dose PTH (like daily administration of teriparatide) induces bone formation more than resorption.