The hypothalamic clock controls circadian pain by rhythmically influencing pain sensitivity. The suprachiasmatic nucleus (SCN) in the hypothalamus is the main pacemaker of the mammalian circadian system and synchronizes circadian rhythms throughout the body. The SCN coordinates physiological rhythms including activity, sleep, body temperature, and hormone secretion. Hypothalamic A11 nuclei regulate the circadian rhythm of mechanonociception in the spinal cord via dopamine receptors and clock genes. A11 pathology disorder reduces dopamine content in the lumbar spinal cord, leading to loss of rhythm. On a fast time scale, hypothalamic clock circuits rhythmically inhibit sensitivity to nociceptive stimuli and determine when pain is most pronounced. These interactions show bidirectional relationships between circadian rhythms and pain.[1][2][4][5]