Artificial light at night and melatonin suppression: an underrecognized neuroendocrine risk factor

Artificial light at night (ALAN) has become an unavoidable feature of modern living, yet its biological consequences remain underestimated in clinical and public health discourse. Chronic exposure to nocturnal light disrupts melatonin secretion, alters circadian signaling, and interferes with neuroendocrine homeostasis. Emerging evidence links ALAN-induced melatonin suppression to sleep disorders, metabolic dysregulation, immune dysfunction, and increased risk of neuropsychiatric and cardiometabolic diseases. This Letter highlights ALAN as a modifiable environmental exposure with significant neuroendocrine implications and emphasizes the need for translational research and preventive strategies.