October 2020 | Reviewed by: Shelley Hershner, MD and Andrea Matsumura, MD
What is melatonin?
Melatonin is a hormone that is naturally produced by your body and plays an important role in sleep. It helps regulate your sleep-wake cycle by signaling to your body when the time for sleep is approaching. Melatonin supplements are widely available and can be effective for circadian rhythm disorders. A circadian rhythm disorder is when your body’s biological clock is out of sync with societal norms including with your obligations. Some examples of circadian rhythm disorders are delayed sleep-wake phase (night owl), jet lag, and shift work disorder.
When it gets dark at nighttime your body starts to produce melatonin. Melatonin starts your body clock and prepares you for sleep. Melatonin levels usually rise in the evening and remain high throughout the night. Levels drop in the morning when it is time to be awake.
What are the forms of melatonin?
Over-the-counter melatonin supplements are available in doses of 1-10 mg. Melatonin is sold as a dietary supplement and is not regulated by the FDA. So, it is possible for the content of the supplement to differ from what is listed on the product label. Before you take melatonin be sure the brand is reputable and discuss taking this and any supplement with your doctor. The American Academy of Sleep Medicine states that melatonin supplements appear to be safe. There is no evidence of serious risks related to their use, but the long-term effects are unknown.
Snacks and beverages marketed as “relaxation” or “chill out” products containing various doses of melatonin along with other ingredients also are available. These products are not regulated by the FDA and are not guaranteed to be effective.
What are benefits and side effects of melatonin?
Melatonin is most effective in treating sleep disorders related to your body clock. It can be used to shift the timing of your sleep. This is best done in conjunction with other treatment under the supervision of a sleep doctor.
Many people use melatonin to self-medicate for insomnia. There is little to no evidence that it works as a sleep aid for this purpose. It is best to see a sleep doctor who will recommend treatment for insomnia.
How can melatonin treat circadian rhythm disorders?
Your use of melatonin to help treat your circadian rhythm disorder should be overseen by a sleep doctor. The timing and dosage will vary for each person. Melatonin may be beneficial in the treatment of the following disorders:
Jet lag
Research strongly suggests that melatonin is effective in reducing the symptoms of jet lag. Doctors recommend taking melatonin before your intended bedtime, beginning before the start of your trip and continuing for a few days after your arrival. Small doses may be effective for minimizing the effects of jet lag.
Shift work
Melatonin may help improve sleep quality and duration for some night shift workers. Take melatonin after the end of your shift, prior to your intended bedtime. But don’t take melatonin before your drive home.
Delayed sleep-wake phase
If you regularly go to bed late at night and wake up late in the morning you may have delayed sleep-wake phase. This occurs when the timing of your circadian rhythms is delayed by two or more hours. Taking melatonin may help you go to sleep earlier. Typically, a small dose before you normally fall asleep may help.
Melatonin may also be helpful for other circadian rhythm sleep disorders including advanced sleep-wake phase, free-running type or irregular sleep-wake rhythm.
What is the dosage for melatonin?
Researchers aren’t certain which dose of melatonin is most effective. It has been studied at doses ranging from 0.3 mg to 10 mg. It is possible for a small dose to work better than a large dose. A dose of about 0.3 mg closely resembles the level of your body’s natural melatonin production. Larger doses cause the melatonin in your blood to peak at a much higher level.
Studies show that timing may be more important than dose. The most effective time to take melatonin is different for everyone and can vary depending on your sleep problem. In certain cases, melatonin may be even more effective when used as part of a treatment plan that also includes bright light therapy.
What are the side effects of melatonin?
No serious side effects have been linked to melatonin use. The effects of long-term use have not been studied and are not known. Melatonin may be unsafe when combined with some medications including those prescribed for mental health disorders.
Talk to your medical provider before taking melatonin. If you think you have a sleep disorder, a sleep doctor can determine what treatment is right for you.