It is estimated that about one third of the population worldwide complains of sleep deprivation or the feeling of insufficient or non-restorative sleep. Some common consequences of insufficient or disturbed sleep include reduced mental alertness and habitual performance, lower productivity, greater difficulty in getting along with family members, colleagues and friends, higher risk of accidents and falls, especially in older people, greater fragility to external influences.

The guardian of sleep is melatonin, which is enhanced by a number of plants promoting physiological restorative sleep.