In order to define the relationship between growth hormone (GH) and peak bone mass, and the importance of the role played by GH in reaching optimal peak bone mass, several questions, discussed in this article, have first to be answered. Although the answers to some of these questions are already becoming apparent, some await the findings of further research. It is doubtful whether the results of these studies, which by definition should be long-term because of the long lag between the end of linear growth and the attainment of peak bone mass, will soon be available. In the absence of evidence-based medicine one can, however, conclude that long-term GH replacement therapy for GH deficiency in adults has no deleterious effects on bone. Indeed, despite an increase in bone turnover and an increase in remodeling space, bone mineral density and bone mineral content have been shown to increase slowly over time and to the same degree in both controlled and uncontrolled studies.