Monitoring the effects of therapy is one way of demonstrating the value of treatment to patients. Since the effect of antiresorptive and anabolic therapy is bone-specific, there is an intuitive appeal to perform serial monitoring to assess clinical effectiveness. The longer term effects of therapy can be monitored by BMD measurements, and over a shorter period of time, by measuring bone turnover markers. Both measurements are used in clinical trials, but their application to individual patients is less clear cut.