Melatonin has a reputation as a health supplement, but it is also produced naturally by the human brain. As a hormone, melatonin helps regulate the sleep/wake cycle, as well as other bodily functions. Melatonin levels are highest at night before sleep. The substance can also be found in many natural foods such as seeds and some fruits, but is most commonly sold over the counter as a synthetic hormone.
Jet Lag
The best evidence for melatonin as a health aid is its effect on jet lag. After traveling across multiple time zones, getting to sleep at the proper time and staying awake during the day can be a challenge. According to Medline Plus, taking melatonin on the day of travel and continuing to take it through the week quickens the time to lock in the new sleep pattern, as well as reducing the time to get to sleep and improving sleepiness during the day.
Falling Asleep
For sleepers with a primary sleep disorder such as delayed sleep phase syndrome, melatonin can reduce the time to fall asleep, as referenced by a literature review published by the U.S. Department of Health and Human Services. However, contrary to popular thought, there is no evidence that melatonin is useful for those with insomnia, nor is there much evidence for melatonin's usefulness for normal sleepers. Studies of the effects of melatonin on elderly people with insomnia have had some mixed results, but these studies are considered preliminary at best.
Hormone Replacement
Melatonin also plays a role with reproductive system, effecting the ovarian, or menstrual, cycle. A 2005 study in the Annals of the New York Academy of Sciences suggests that melatonin supplements may delay menopause due to the link between nighttime declines of melatonin and the onset of menopause. The researchers also reported improved thyroid function and a decline in menopause-related depression.
Bizarre Dreams
Researchers from Santa Clara University discovered that melatonin also affects the content of dreams. Based on a two-week study published in 2000 in the journal "Sleep and Hypnosis," researchers found that 6 mg of melatonin significantly alters dream content compared to placebo. In particular, dreams were analyzed to contain more "transformations of objects" and "overall transformations." Perhaps this effect is due to the increased time it takes normal sleepers who take melatonin to get into REM, or dreaming sleep, latency, as reported by the U.S. Department of Health and Human Services in their melatonin literature review. A 2010 study published in the journal "Sleep Medicine" also suggests that increased REM latency is associated with higher levels of nightmares. The authors recommend that nightmare sufferers be screened for REM-inhibiting medications and supplements.
References
- Medline Plus: Melatonin
- US Department of Health and Human Services: Melatonin for Treatment of Sleep Disorders
- Annals of the New York Academy of Sciences: Effects of melatonin in perimenopausal and menopausal women
- "Sleep and Hypnosis": Effects of melatonin on dream bizarreness among male and female college students
- "Sleep medicine": REM sleep characteristics of nightmare sufferers before and after REM sleep deprivation
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