Journal of Advances in Medicine and Medical Research

Age-associated endocrine change is frequently described in the language of deficiency, yet a lower circulating hormone concentration does not necessarily establish disease or demonstrate that replacement will improve health. This critical narrative review examines the growth hormone–insulin-like growth factor-1, thyroid, gonadal and adrenal axes, focusing on the distinction between adaptive remodelling, pathological endocrine failure and potentially reversible effects of illness, adiposity, medication and altered feedback. Peer-reviewed observational studies, randomised trials, evidence syntheses and professional guidance were examined alongside developmental endocrinology literature, with evidence considered up to 23 August 2026. Across the four axes, the clinical implications of similar age-associated laboratory changes are strikingly different. Reduced somatotropic signalling may entail trade-offs between growth, metabolic maintenance and disease resistance, while growth hormone administration to otherwise healthy older adults has not shown compelling functional benefit. Mild thyrotropin elevation in later life often occurs without low free thyroxine, and trials have not demonstrated meaningful average symptomatic gains from routine levothyroxine in older adults with mild subclinical hypothyroidism. Ovarian menopause is a distinctive physiological transition for which hormone therapy may provide important symptom and skeletal benefits in appropriately selected individuals, whereas testosterone treatment requires biochemical and clinical evidence of hypogonadism and careful monitoring. Adrenal androgen decline is not equivalent to adrenal insufficiency, and replacement studies do not support indiscriminate use of dehydroepiandrosterone for healthy ageing. Developmental comparisons show why the same hormone concentration can represent normality, disease or treatment response at different life stages. A clinical decision framework is proposed that weighs trajectory, symptoms, feedback integrity, functional outcomes and intervention evidence rather than chronological age or a single assay result. Future studies should prioritise longitudinal within-person measurements, age-sensitive reference intervals, functional outcomes and life-course follow-up. Endocrine ageing is best understood as heterogeneous remodelling with discrete, clinically important exceptions requiring targeted treatment.