When ass essing the function of the endocrine system in elderly patients, it is important to distin- guish between the effects of aging per se on en- docrine physiology from those caused by disease- related changes. Notably, diagnosis of endocrine dysfunction in the elderly not always requires therapeutic intervention (e.g. in some cases of subclinical hypothyroidism). The age-related hy- pothalamic-pituitary-gonadal axis insufficiency in women is well defined and studied, and guidelines for HRT after menopause are well defined. On the other hand, the function of GH-IGF-1 system, of the male hypothalamic-pituitary-gonadal axis, and of zona reticularis (the layer of adrenal cortex syn- thesizing DHEA) decline progressively with age in most people and age-adjusted ranges of normal values for serum IGF-1, testosterone and DHEA concentrations can be defined. However, a routine replacement therapy with GH, testosterone and DHEA in the elderly remains a matter of debate and administration of such therapy is still not evidence- based. The secretion of other hormones is also
influenced by physiological aging but since these changes are much less predictable and still insuf- ficiently investigated, recommendations for routine supplementation cannot be formulated.