48 patients scheduled for cementless total hip arthroplasty (THA) were randomized to be postoperatively administered either daily subcutaneous teriparatide, weekly oral alendronate, or no medication. The purpose of this study was to measure and compare periprosthetic bone mineral density, defined by Gruen Zones, between groups over 48 week follow-up. In addition, serum levels of procollagen type-1 N-terminal propeptide (P1NP) and N-terminal telopeptides of type-1 collagen (NTx) were measured and assessed during follow-up. The largest decrease in BMD in all three groups was observed in Gruen Zone 7, and the degree of this decrease was significantly smaller in both the teriparatide group and alendronate group compared to the no medication group, though the difference between the teriparatide and alendronate groups was not statistically significant.