Melatonin can be effective for people who have problems related to the timing of when they sleep and wake. These problems are known as “circadian rhythm sleep disorders.” You can take melatonin to “trick” the brain into believing it is night.
When taken at the proper time, melatonin can produce a shift in the timing of your sleep period. This can help when the timing of your sleep-wake cycle needs to be corrected. As a result your sleep cycle will line up better with your work or school schedule. In general, taking melatonin in the morning shifts your circadian rhythms later; taking melatonin in the evening shifts the rhythms earlier.
Melatonin is most effective in the treatment of these circadian rhythm sleep disorders:
Jet lag disorder is a temporary problem that occurs when you cross time zones. The timing of your body’s sleep-wake cycle becomes misaligned. It doesn’t match the timing of when you should sleep and be awake at your new location. Symptoms tend to be most severe when traveling eastward.
A high level of evidence supports melatonin as a standard treatment for jet lag. When used at the right time, it can reduce jet lag symptoms and improve sleep after you cross multiple time zones. Treatment may begin a few days prior to departure and continue for a few days after arrival. Doses of 0.5 mg to 5 mg may be effective.
Shift work disorder occurs when you have a non-standard work schedule. Examples include night shifts, early-morning shifts and rotating shifts. The schedule forces you to sleep at a time of day when your body expects to be awake. An estimated 20 percent of U.S. workers are involved in some form of shift work.
A moderate level of evidence supports melatonin as a treatment for night-shift workers. It should be taken after working a night shift and before daytime sleep. It should not be taken before driving home. Melatonin can improve daytime sleep quality and duration for night-shift workers. The two studies that provided the best results used doses of about 2 mg to 3 mg. Other doses of 0.5 mg to 10 mg also have been studied. Effectiveness does not always depend on the strength of the dosage.
Delayed sleep phase disorder (DSP) occurs when the timing of your circadian rhythms is delayed by two or more hours. As a result you regularly go to bed late at night and wake up late in the morning.
A moderate level of evidence supports melatonin as a treatment for DSP. Taking melatonin in the afternoon or evening shifts your sleep cycle to an earlier time. This helps you go to sleep earlier. Melatonin treatment reduces the time it takes you to fall asleep. It does not change your total sleep time or your daytime alertness. Doses studied range from 0.3 mg to 5 mg. Effective timing ranged from 1.5 hours to 6 hours before bedtime. For DSP melatonin is best used in combination with bright light therapy in the morning.
Melatonin also may be helpful if you have advanced sleep phase disorder, free-running type or irregular sleep-wake rhythm. There is only limited evidence to support the use of melatonin to treat insomnia. At best it only produces a mild improvement in symptoms. More effective treatments for insomnia are medications and cognitive behavioral therapy.
