The pineal gland plays a central role in regulating the sleep cycle by producing melatonin, a type of hormone. In people with normal sleep cycles, melatonin levels increase in the evening and stay high throughout the night. They decrease early in the morning, signaling the body that it is time to wake up. Melatonin production depends on several factors, one of which is the amount of light available. This is why sleep experts recommend making the bedroom as dark as possible for sleep. Since the days get shorter in the winter, the reduced amount of light may cause the pineal gland to produce melatonin earlier in the evening. In some people, this contributes to the symptoms of seasonal affective disorder. For those who have difficulty sleeping, a synthetic form of melatonin is available. Using melatonin supplements for sleep has several benefits, but the melatonin can also cause side effects.
Uses of the Melatonin Supplement for Sleep
There are several reasons to use melatonin for sleep aid purposes. People with insomnia may use melatonin supplements to regulate their sleep cycles. Insomnia makes it difficult to fall asleep or stay asleep at night. Taking melatonin decreases the amount of time it takes to fall asleep by approximately 12 minutes. Some people who take melatonin for insomnia report that they sleep better after taking the supplements, but researchers have been unable to verify this claim.
Investigators from the Agency for Healthcare Research and Quality reviewed the results of several research studies on melatonin. They found that melatonin did not improve sleep efficiency – the percentage of time the subjects stayed asleep during the time they had set aside for sleep – or sleep quality in people with primary sleep disorders. The results were a little different in those with secondary sleep disorders, which are sleep disorders caused by underlying physical or psychological conditions. In study subjects with this type of sleep disorder, the melatonin did improve sleep efficiency.
Sleep Disorders Related to Blindness
The amount of light available affects the amount of melatonin produced by the pineal gland. For this reason, people with blindness may not produce enough melatonin. Researchers have found that melatonin supplements may benefit those who have sleep disorders as a result of their blindness. In 1977, Dr. Laughton Miles confirmed that one of his patients developed a 24.9-hour circadian rhythm due blindness. For more than 20 years following this revelation, researchers tried to develop a solution to this problem. It was not until 1999 that scientists revealed that a daily dose of melatonin may restore the normal sleep cycle in blind people. Dr. Robert L. Sack and a team of researchers from the Sleep and Mood Disorders Laboratory at Oregon Health Sciences University found that 10 mg of melatonin per day restored normal circadian rhythms in 85 percent of study subjects.
Jet lag is a change in circadian rhythm that occurs when someone travels rapidly across time zones. When someone travels frequently, jet lag can cause a serious disturbance in the sleep cycle, making it difficult to fall asleep or get enough sleep at night. Surprisingly, the direction you travel determines the effects of jet lag. Traveling east typically causes difficulty falling asleep at the local bedtime and difficulty getting up in the morning. Traveling west typically leads to sleepiness early in the evening and earlier-than-usual awakening. Columbia University Health Services recommends taking melatonin in the morning when traveling west and taking it in the evening when traveling east.
Delayed Sleep Phase Syndrome
People with a condition called delayed sleep phase syndrome (DSPS) do not fall asleep until very late at night or early in the morning. This condition is a disorder of the circadian rhythm, just like jet lag. Melatonin supplements may reset the circadian rhythm so that people with DSPS can fall asleep earlier. Research indicates that exposure to artificial light or sunlight to increase alertness may be just as helpful as using melatonin, however.
Sleep Disorders Related to Shift Work
Shift workers may have difficulty getting to sleep after their shifts due to environmental stimuli such as increased light and noise. Several studies show that melatonin may be effective for helping shift workers fall asleep, but a low dose of 2 mg does not have the same effect as a dose of 10 mg. Melatonin supplements improve sleep duration during the day, increase alertness during the night shift and improve sleep quality overall.
Proper Melatonin Dosage for Sleep
The correct amount of melatonin for sleep depends on a person’s age and the severity of the sleep problem. The typical dosage ranges from just 1 to 3 mg of melatonin. Although higher doses may be more effective more some people, it is wise to consult a physician before taking high doses of this hormone. Too much melatonin can cause additional sleep disturbances and leave users feeling groggy and fatigued.
Melatonin for Children with Sleep Problems
Melatonin has also been used to treat sleep problems in children with primary disorders. Conditions such as mental retardation and autism sometimes result in disturbances of the sleep-wake cycle. These disturbances may also occur in children who have disorders of the central nervous system. When given to children, melatonin appears to reduce the amount of time it takes to fall asleep.
Side Effects of Melatonin for Sleep
Because melatonin affects the sleep cycle, one of the most common side effects of melatonin supplements is daytime sleepiness. Other possible side effects include headaches, irritability, dizziness, anxiety, confusion and depression symptoms. When taken with diabetes medications, blood thinners, birth control pills and immunosuppressants, melatonin can cause serious drug interactions. Anyone considering melatonin for sleep should consult a physician before taking it with prescription or over-the-counter medications. The National Sleep Foundation says that melatonin supplements may be dangerous for people with kidney disease, high blood pressure, heart problems and a history of stroke, as well as pregnant women, as this hormone affects fertility and causes blood pressure changes when administered to animals.