Sleep-inducing effects of low doses of melatonin ingested in the evening*

Abstract

We previously observed tht low oral doses of melatonin given at noon increase blood melatonin concentrations to those normally occurring nocturnally and facilitate sleep onset, as assessed using and involuntary muscle relaxation test. In this study we examined the induction of polysomnographically recorded sleep by similar doses given later in the evening, close to the times of endogenous melatonin release and habitual sleep onset. Volunteers received the hormone (oral doses of 0.3 or 1.0 mg) or placebo at 6, 8, or 9 PM. Latencies to sleep onset, to stage 2 sleep, and to rapid eye movement (REM) sleep were measured polysomnographically. Either dose given at any of the three time points decreased sleep onset latency and latency to stage 2 sleep. Melatonin did not suppress REM sleep or delay its onset. Most volunteers could clearly distinguish between the effects of melatonin and those of placebo when the hormone was tested at 6 or 8 PM. Neither melatonin dose induced "hangover" effects, as assessed with mood and performance tests administered on the morning after treatment. These data provide new evidence that nocturnal melatonin secretion may be involved in physiologic sleep onset and that exogenous melatonin may be useful in treating insomnia.

Effect of melatonin administration on subjective sleep quality in chronic obstructive pulmonary disease

“…When used near the time of habitual sleep, melatonin has produced less consistent results. Nocturnal administration has been reported to promote sleep (23,24), to have no significant clinical benefit (25) or to even increase wake time after sleep onset (26). Such variability may be related to differences in inclusion and exclusion criteria, outcome measures, hormone dose, and routes and timing of its administration.…”

Unveiling the role of melatonin MT2 receptors in sleep, anxiety and other neuropsychiatric diseases: a novel target in psychopharmacology

“…In cats, exogenous MLT (0.01-1 mg/ kg) significantly increased SWS, but the effect was weak and lasted for only 2 hours. 72 There is a large body of research demonstrating hypnotic effects of MLT in clinical studies, [73][74][75][76][77] although some studies failed to find significant effects, 78,79 and therefore its clinical efficacy is still unclear. 80 These discrepant results may originate from the pharmacological constraints of generic MLT, limiting its clinical use: short half-life (< 1 hr), high first-pass metabolism, binding of multiple receptors and effects dependent on time of the day or phase of circadian rhythm.…”

Abnormal nocturnal melatonin secretion and disordered sleep in abstinent alcoholics

“…Melatonin is thought to have effects on sleep by resetting the internal biological clock (Brzezinski, 1997), whereas circulating concentrations of cortisol are not reliably associated with sleep measures of continuity (Friess et al 1995). Indeed, early evening administration of melatonin has been found to decrease sleep latency and increase sleep efficiency in the elderly (Zhdanova et al 2001) and in patients with primary insomnia (Garfinkel et al 1995;Haimov et al 1995;Zhdanova et al 1995;Girardin et al 1998) but have no effects on measures of sleep architecture or REM sleep (Zhdanova et al 2001). Likewise, in older adults and psychiatric populations such as depressed patients, melatonin onset and/or peak values are altered in association with disturbances of sleep continuity (Nair et al 1984;Beck-Friis et al 1985;Kennedy et al 1989;Dijk et al 1999).…”