Principles of Hormone Replacement

The aim of hormone replacement is to replace the missing physiological effects of a deficient hormone. The last century identified most of the endocrine hormones, which can now be replaced when deficient; however, the challenge of the twenty-first century is to optimize replacement. The guiding principle in hormone replacement is replicating the natural levels and rhythms of hormones at different ages but this requires a good understanding of physiology. There is a need for better biomarkers of hormone actions and using these to develop new ways to deliver hormone replacement tailored to the individual. This chapter discusses current approaches to this problem.