Osteoporosis is characterized by decreased bone strength and it is prevalent among postmenopausal women but also occurs in men and women with underlying conditions or major risk factors associated with bone demineralization. Its chief clinical manifestations are vertebral and hip fractures, although fractures can occur at any skeletal site.The World Health Organization (WHO) operationally defines osteoporosis as a bone density that falls 2.5 standard deviations (SD) below the mean for young healthy adults of the same gender-also referred to as T-score of -2.5. Postmenopausal women who fall at the lower end of the young normal range (a T-score of >1 SD below the mean) are defined as having low bone density (osteopenia) and are also at increased risk of osteoporosis. More than 50% of the fractures, including hip fractures, among postmenopausal women occur in this group.

Teriparatide is one of the most effective treatment options for osteoporosis. But the cost of teriparatide is prohibitively expensive and in countries like India with limited personal resources of the individuals, its not a feasible option in the majority of the patients with severe osteoporosis. The investigators aim to compare weekly versus daily teriparatide therapy in an open label non inferiority trial and if successful, the investigators anticipate, the cost of treatment could be reduced considerably so that treatment becomes more affordable to a larger number of patients. Also with weekly therapy, number of multiple injections could be brought down.

Inclusion Criteria:

• Postmenopausal women of age group 50-70 having T score less than -2.5 SD or lower at lumbar spine or proximal femur.

Exclusion Criteria:

• Patients with renal dysfunction (serum creatinine >1.5)
• Primary and secondary hyperparathyroidism
• Secondary osteoporosis
• Unexplained elevated ALP (alkaline phosphatase)
• History of therapeutic radiation
• Active malignancy and patients having implant
• Patients who have received i.v. or oral bisphosphonates in their disease course