Melatonin is a hormone found naturally in the body. Melatonin used as medicine is usually made 
synthetically in a laboratory. It is most commonly available in pill form, but melatonin is also available in forms that can be placed in the cheek or under the tongue. This allows the melatonin to be absorbed directly into the body.
Melatonin’s main job in the body is to regulate night and day cycles or sleep-wake cycles. Darkness causes the body to produce more melatonin, which signals the body to prepare for sleep. Light decreases melatonin production and signals the body to prepare for being awake. Some people who have trouble sleeping have low levels of melatonin. It is thought that adding melatonin from supplements might help them sleep.
People use melatonin to adjust the body’s internal clock. It is used for jet lag, for adjusting sleep-wake cycles in people whose daily work schedule changes (shift-work disorder), and for helping blind people establish a day and night cycle.
Melatonin is also used for the inability to fall asleep (insomnia); delayed sleep phase syndrome (DSPS); insomnia associated with attention deficit-hyperactivity disorder (ADHD); insomnia due to certain high blood pressure medications called beta-blockers; and sleep problems in children with developmental disorders including autism, cerebral palsy, and mental retardation. It is also used as a sleep aid after discontinuing the use of benzodiazepine drugs and to reduce the side effects of stopping smoking.
How effective is it?
Natural Medicines Comprehensive Database rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, Ineffective, and Insufficient Evidence to Rate.
The effectiveness ratings for MELATONIN are as follows:
Likely effective for…
- Sleeping problems in children with autism and mental retardation. Taking melatonin by mouth is helpful for disturbed sleep-wake cycles in children and adolescents with mental retardation, autism, and other central nervous system disorders. Melatonin also appears to shorten the time it takes for to children with developmental disabilities (cerebral palsy, autism, and mental retardation) to fall asleep.
Possibly effective for…
- Jet lag. Most research shows that melatonin can improve certain symptoms of jet lag such as alertness and movement coordination. Melatonin also seems to improve, to a lesser extent, other jet lag symptoms such as daytime sleepiness and tiredness. But, melatonin might not be effective for shortening the time it takes for people with jet lag to fall asleep.
- Trouble sleeping (insomnia). Melatonin seems to be able to shorten the amount of time it takes to fall asleep, but only by about 12 minutes, according to one research study. Melatonin does not appear to significantly improve “sleep efficiency,” the percentage of time that a person actually spends sleeping during the time set aside for sleeping. Some people say melatonin makes them sleep better, even though tests don’t agree. There is some evidence that melatonin is more likely to help older people than younger people or children. This may be because older people have less melatonin in their bodies to start with.
There is some interest in finding out whether melatonin might help with “secondary insomnia.” This is trouble sleeping that is related to other conditions such as Alzheimer’s disease; depression; schizophrenia; hospitalization; and “ICU syndrome,” sleep disturbances in the intensive care unit. Research to date suggests that melatonin might not help to reduce the time it takes to fall asleep in secondary insomnia, but it might improve sleep efficiency.
- Cluster headaches. Taking 10 mg of melatonin by mouth every evening might reduce the number of cluster headaches. However, taking 2 mg of melatonin at bedtime doesn’t seem to work.
- Reducing anxiety before surgery. Melatonin used under the tongue seems to be as effective in reducing anxiety before surgery as midazolam, a conventional medication. It also seems to have fewer side effects in some people.
- Helping elderly people sleep after they stop taking a type of drug called benzodiazepines. The controlled-release form of melatonin is the type that was shown to work for this.
- Helping decrease symptoms in people who are quitting smoking. A single oral dose of 0.3 mg of melatonin taken 3.5 hours after stopping cigarettes seems to reduce anxiety, restlessness, irritability, depression, and cigarette craving over the next 10 hours.
- Low blood platelets (thrombocytopenia).
- Improving the effectiveness of certain cancer medications used to fight tumors in the breast, lung, kidney, liver, pancreas, stomach, colon, prostate, and decreasing some side effects of cancer treatment.
- Decreasing symptoms of a movement disorder called tardive dyskinesia (TD).
- Decreasing sunburn when applied to the skin in a cream form before going into the sun.
Possibly ineffective for…
- Adjusting sleep schedule in people that do shift work.
Likely ineffective for…
- Depression. There is also some concern that melatonin might worsen symptoms in some people.
Source: Natural Medicines Comprehensive Database Consumer Version [Internet]. Stockton (CA): Therapeutic Research Faculty; ©1995- . Melatonin, http://www.nlm.nih.gov/medlineplus/druginfo/natural/940.html
Curated by My Medical Forum
