The purpose of this study is to compare the pharmacokinetics (blood levels) of two teriparatide products, PF708 and Forteo, in healthy subjects.

This is a double-masked, randomized, two-treatment cross-over study in healthy adult subjects. Half of the subjects will be randomized to receive PF708 first and Forteo second (Sequence A), and the other half will be randomized to receive the drugs in reverse sequence (Sequence B),

Inclusion Criteria:

• Male or female aged 18-50 years at the time of Informed Consent.
• Able to understand and sign the written Informed Consent Form (ICF).

Exclusion Criteria:

• History of or positive test result for human immunodeficiency virus (HIV), hepatitis C virus [test for hepatitis C virus antibody (HCV Ab)] or hepatitis B virus [test for hepatitis B surface antigen (HBsAg)].
• Female subjects who are pregnant or have a positive pregnancy test result, currently breastfeeding, or planning to become pregnant during the course of the study.
• Blood donation (greater than or equal to 500 mL) within 30 days prior to screening.
• History of Paget's disease of bone.
• History of prior external beam or implant radiation therapy involving the skeleton.
• Active urolithiasis or primary hyperparathyroidism.
• History of alcohol or substance abuse within 3 years prior to screening.
• Previous treatment, including for investigational purposes, with any products (e.g., Forteo, Natpara) derived from human parathyroid hormone (PTH).