Dosages of PTH ranged markedly across trials. They were variously reported in micrograms or units per day in the different articles. Furthermore, because of different combinations across trials and different comparison groups, conclusions regarding dose effects are difficult. Three trials28,30,31 directly compared different dosages of PTH with each other. The first30 of the 3 compared 50, 100, and 200 U/wk SC for 48 weeks. Corresponding amounts of the peptide were 15, 30, and 50 µg, respectively. Increases in lumbar bone mineral density (BMD) were dose-related (range, 0.6%-8.1%), but there were no changes at the femoral neck with any PTH dosage. The second trial31 compared 50, 75, or 100 µg/d SC for 1 year, followed by alendronate alone for 1 year. Although all dosages increased spine and femoral neck BMD compared with placebo, specific dose-effect analysis was not presented. Increases in bone density ranged from 4.3% to 9.2% at the lumbar spine. Although there was no change at the femoral neck with PTH compared with placebo, the group treated with PTH followed by alendronate had better femoral neck bone density than the group treated with placebo followed by alendronate. The third trial28 compared 20 or 40 µg/d SC with placebo for 16 to 17 months. Both dosages increased spine and hip (total hip, femoral neck, and trochanter) BMD compared with placebo, but dose-effect analysis per se was not provided. Bone density increases with 20-µg dosaging were 9.7%, 2.6%, 2.8%, and 3.5% at the lumbar spine, total hip, femoral neck, and femoral trochanter, respectively. Corresponding values for the 40-µg/d dosage were 13.7%, 3.6%, 5.1%, and 4.4%. Both dosages were associated with decreases in radius BMD (−2.1% and −3.2% for 20- and 40-µg/d dosages, respectively) compared with placebo (Table 2).