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Melatonin

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What other names is Melatonin known by?

5-Methoxy-N-Acetyltryptamine, MEL, Melatonina, Mélatonine, MLT, N-Acetyl-5-Methoxytryptamine, N-Acétyl-5-Méthoxytryptamine, Pineal Hormone.

What is Melatonin?

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.

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); rapid eye movement sleep behavior disorder (RBD); 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 intellectual disabilities. It is also used as a sleep aid after discontinuing the use of benzodiazepine drugs and to reduce the side effects of stopping smoking.

Some people use melatonin for Alzheimer's disease or memory loss (dementia), bipolar disorder, a lung disease called chronic obstructive pulmonary disease (COPD), insomnia caused by beta-blocker drugs, endometriosis, ringing in the ears, depression or seasonal affective disorder (SAD), mild mental impairment, nonalcoholic liver disease, chronic fatigue syndrome (CFS), fibromyalgia, restless leg syndrome, an inflammatory disease called sarcoidosis, schizophrenia, migraine and other headaches, age-related vision loss, benign prostatic hyperplasia (BPH), irritable bowel syndrome (IBS), bone loss (osteoporosis), a movement disorder called tardive dyskinesia (TD), acid reflux disease, Helicobacter pylori (H. pylori), exercise performance, infertility, epilepsy, aging, for menopause, metabolic syndrome, for recovery after surgery, agitation caused by anesthesia, stress, involuntary movement disorder (tardive dyskinesia), changes in heart rate when you move from laying down to sitting up (postural tachycardia syndrome), delirium, inability to control urination, jaw pain, inflammatory bowel disease (ulcerative colitis), and for birth control.

Other uses include breast cancer, brain cancer, lung cancer, prostate cancer, head cancer, neck cancer, and gastrointestinal cancer. Melatonin is also used for some of the side effects of cancer treatment (chemotherapy) including weight loss, nerve pain, weakness, and a lowered number of clot-forming cells (thrombocytopenia).

It is also used to calm people before they are given anesthesia for surgery.

The forms of melatonin that can be absorbed through the cheek or under the tongue are used for insomnia, shift-work disorder, and to calm people before receiving anesthesia for surgery.

Sometimes people apply melatonin to the skin to protect against sunburn.

Melatonin may also be injected into the muscle to help treat cancer.

Is Melatonin effective?

Melatonin can help correct certain sleep disorders in blind people. It is also effective for correcting sleeping problems in children with autism and mental retardation.

There is some scientific evidence that melatonin might improve alertness in people with jet lag. But it doesn't seem to be as useful for other jet lag symptoms such as daytime sleepiness. Melatonin might also be helpful for insomnia for some people.

There is also some evidence that melatonin might improve the effectiveness of cancer drugs used to fight tumors in the breast, lung, kidney, liver, pancreas, stomach and colon. But it should only be used for this purpose with the help of a healthcare professional.

Melatonin might also reduce pain in people with a certain kind of headache called a "cluster headache."

There is some evidence that a melatonin cream may help decrease sunburn when used before going into the sun.

A lot of people try melatonin to help adjust their sleeping schedule when they do shift work, but melatonin does not seem to work for this use.

There isn't enough information to know if melatonin is effective for the other conditions people use it for including: ringing in the ears, osteoporosis, epilepsy, birth control, aging, and others.

Likely Effective for...

  • Sleep disorders in blind people. Taking melatonin by mouth helps improve sleep disorders in blind children and adults.
  • Trouble falling asleep (delayed sleep phase syndrome). Taking melatonin by mouth appears to reduce the length of time needed to fall asleep in young adults and children who have trouble falling asleep. However, within one year of stopping treatment, this sleeping problem seems to return.
  • Sleeping problems in people with sleep-wake cycle disturbances. Taking melatonin by mouth is helpful for disturbed sleep-wake cycles in children and adolescents with intellectual disabilities, autism, and other central nervous system disorders. Melatonin also appears to shorten the time it takes for to children with developmental disabilities to fall asleep. In addition, melatonin appears to improve sleep quality in people with reduced rapid-eye movement (REM) sleep. Also, melatonin appears to reduce the time it takes to fall asleep and the number of sleep interruptions in elderly people with sleep-wake cycle disturbances and dementia.

Possibly Effective for...

  • Insomnia caused by beta-blocker drugs. Beta-blocker drugs, such as atenolol and propranolol, are a class of drugs that seem to lower melatonin levels. This might cause problems sleeping. Research suggests that taking a melatonin supplement might reduce this side effect.
  • Painful uterus disorder called endometriosis. Research suggests that taking melatonin daily for 8 weeks reduces pain by 39.3% and painkiller use by 46%. It also reduces pain during menstruation, intercourse, and while going to the bathroom.
  • High blood pressure. Taking the controlled-release form of melatonin before bedtime seems to lower blood pressure in people with high blood pressure. Immediate-release formulations do not seem to work.
  • Insomnia. For primary insomnia (insomnia that is not related to a medical or environmental causes), melatonin seems to shorten the amount of time it takes to fall asleep, but only by about 12 minutes. Melatonin does not appear to 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 do not 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," which involves 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.
  • Jet lag. Most research shows that melatonin can improve certain symptoms of jet lag such as alertness and movement coordination. Melatonin also seems to slightly improve 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.
  • Reducing anxiety before surgery. Melatonin used under the tongue seems to be as effective at reducing anxiety before surgery as midazolam, a conventional medication. It also seems to have fewer side effects in some people. Taking melatonin by mouth also seems to reduce anxiety before surgery, although some conflicting evidence exists.
  • Tumors. Taking high doses of melatonin with chemotherapy or other cancer treatments might reduce tumor size and improve survival rates in people with tumors.
  • Sunburn. Applying melatonin to the skin before sun exposure seems to prevent sunburn
  • Jaw pain (temporomandibular disorder). Research suggests that taking melatonin at bedtime for 4 weeks reduces pain by 44% and increases tolerance to pain by 39% in women wih jaw pain.
  • Low blood platelets (thrombocytopenia). Taking melatonin by mouth can improve low blood platelet counts associated with cancer, cancer treatment, and other disorders.

Possibly Ineffective for...

  • Withdrawal from drugs called benzodiazepines. Early research suggests that taking the controlled-release form of melatonin by mouth seems to help older people with insomnia related to withrdrawal from drugs called benzodiazepines. But the majority of research shows that taking melatonin does not help with benzodiazepine withdrawal in most patients.
  • Weight loss from cancer (cachexia). Research suggests that taking melatonin each evening for 28 days does not improve appetite, body weight, or body composition in people with wasting syndrome from cancer.
  • Memory loss (dementia). Most research suggests that taking melatonin does not improve behavior or affect symptoms in people with Alzheimer's disease or other forms of memory loss. But taking melatonin might reduce confusion and restlessness when the sun goes down in people with these conditions.
  • Exercise performance. Taking melatonin one hour before resistance exercise does not seem to improve performance.
  • Infertility. Taking melatonin does not appear to improve fertility or pregnancy rates in women undergoing fertility treatments. But some research suggests that taking melatonin daily for at least 2 weeks might improve pregnancy rates in women ungergoing IVF.
  • Adjusting sleep schedule in people who do shift work. Taking melatonin by mouth does not seem to improve sleeping problems in people who do shift work.

Likely Ineffective for...

  • Depression. Although melatonin might improve sleeping problems in people with depression, it does not seem to improve depression itself. There is also some concern that melatonin might worsen symptoms in some people. It is not clear if taking melatonin can prevent depression.

Insufficient Evidence to Rate Effectiveness for...

  • Age-related vision loss (age-related macular degeneration). Early research suggests that taking melatonin might delay the loss of vision in people with age-related vision loss.
  • Attention deficit-hyperactivity disorder (ADHD). Limited research suggests that melatonin might reduce insomnia in children with ADHD who are taking stimulants. However, improved sleep does not seem to decrease symptoms of ADHD.
  • Enlarged prostate (benign prostatic hyperplasia). Some research suggests that taking melatonin can reduce excessive urination at night in some men with enlarged prostate.
  • Bipolar disorder. Early research suggests that taking melatonin at bedtime increases sleep duration and reduces manic symptoms in people with bipolar disorder who also have insomnia. But there are also concerns that taking melatonin might make symptoms worse in some people with bipolar disorder.
  • Chronic fatigue syndrome (CFS). Some early research suggests that taking melatonin in the evening might improve some symptoms of CFS, including fatigue, concentration, and motivation. However, other early research suggests that taking melatonin by mouth does not improve CFS symptoms.
  • Lung disease (chronic obstructive pulmonary disease). Some evidence suggests that taking melatonin improves shortness of breath in people with COPD. However, it does not seem to improve lung function or exercise capacity.
  • Cluster headache. Taking melatonin 10 mg by mouth every evening might reduce the frequency of cluster headaches. However, lower doses don't seem to work.
  • Problems with mental function. Taking a mixture of docosahexaeonic acid (DHA), eicosapentaenoic acid (EPA), vitamin E, soy, phospholipids, melatonin, and tryptophan appears to improve mental function, speech, and sensitively to smell in older people with some problems with mental function.
  • Delirium. Evidence suggests that taking melatonin nightly for 14 days reduces the risk of delirium in older people.
  • Indigestion (dyspepsia). Taking melatonin nightly seems to reduce indigestion.
  • Nighttime bedwetting (enuresis). Early research suggests that taking melatonin before bed does not reduce the number of wet beds in children with nighttime bedwetting.
  • Fibromyalgia. Melatonin might decrease the severity of pain and stiffness in people with fibromyalgia.
  • Acid reflux disease. Taking melatonin daily at bedtime might improve symptoms of acid reflux, including heartburn. However, taking conventional medication seems to be more effective.
  • Stomach ulcers caused by H. pylori infection. Evidence suggests that taking melatonin together with the drug omeprazole improves healing in people with ulcers caused by H. pylori infection.
  • Irritable bowel syndrome (IBS). Early research suggests that taking melatonin might improve some, but not all, symptoms of IBS. Some research suggests that melatonin works better in people with IBS in which constipation rather than diarrhea is the main symptom.
  • Menopausal symptoms. Limited research suggests that melatonin does not relieve menopausal symptoms. However, taking melatonin in combination with soy isoflavones might help psychological symptoms associated with menopause.
  • Metabolic syndrome. Early research suggests that taking melatonin reduces blood pressure as well as low-density lipoprotein (LDL or "bad") cholesterol in people with metabolic syndrome.
  • Migraine headache. There is some evidence that taking melatonin before bed can prevent episodic migraine headache. When headaches do occur, they are milder and pass more quickly. However, other evidence shows that taking melatonin does not reduce the frequency of migraine attacks.
  • Withdrawal from nicotine. Taking melatonin 3.5 hours after nicotine withdrawal seems to reduce anxiety, restlessness, and cigarette cravings in smokers.
  • Liver disease (nonalcoholic steatohepatitis). Some evidence suggests that taking melatonin improves markers of liver function in the blood of people with nonalcoholic steatohepatitis.
  • Recovery after surgery. Some evidence suggests that taking melatonin the night before and one hour before undergoing surgery might reduce pain and drug use after surgery.
  • Changes in heart rate when you move from laying down to sitting up (postural tachycardia syndrome). Early research suggests that taking a single dose of melatonin reduces heart rate when you change from sitting to standing. But melatonin does not seem to affect blood pressure or other sympotoms.
  • Prostate cancer. Taking melatonin by mouth together with conventional medications might reduce the growth of prostate cancer.
  • Acting out dreams while sleeping. Some evidence suggests that taking melatonin before bed reduces muscle movement during sleep in people with a sleep disorder that involves acting out dreams.
  • Restless leg syndrome. Early research suggests that taking melatonin before bedtime might make symptoms worse in people with restless leg syndrome.
  • An inflammatory condition called sarcoidosis. Early evidence suggests that taking melatonin daily for one year followed by a reduced dose for a second year improves lung function and skin problems in people with an inflammatory condition called sarcoidosis.
  • Schizophrenia. There is conflicting evidence about the effects of melatonin on schizophrenia symptoms and side effects related to medications. Some research shows that taking melatonin by mouth for 8 weeks reduces weight gain associated with the use of the drug olanzapine and improves symptoms of schizophrenia. But other research suggests that it might not have any benefits and might worsen the side effects of second-generation antipsychotic medications.
  • Seasonal affective disorder (SAD). Some early research suggests that taking melatonin by mouth might reduce depression during the winter in people with SAD. But giving melatonin under the tongue does not seem to improve symptoms.
  • Seizures. There is some evidence that taking melatonin at bedtime may reduce the number and length of seizures in children with epilepsy. However, other evidence suggests that it does not reduce seizures. Melatonin should be used cautiously, because melatonin may increase the number of seizures in some people.
  • Agitation caused by anesthesia drugs. Some evidence suggests that taking melatonin before sevoflurane anesthesia reduces agitation after surgery.
  • Headache characterized by sudden sharp pain. Some evidence suggests that taking melatonin daily might prevent sudden stabbing headaches.
  • Stress. There is some evidence that taking melatonin might improve memory while under stress.
  • Movement disorder (tardive dyskinesia). Some evidence suggests that taking melatonin by mouth decreases symptoms of a movement disorder called tardive dyskinesia. However, other evidence suggests that taking melatonin daily does not reduce involuntary movements in these patients.
  • Ringing in the ears (tinnitus). Some evidence suggests that taking melatonin at night reduces ringing in the ears and improves sleep quality. However, other research suggests that it does not reduce ear ringing.
  • Inflammatory bowel disease (ulcerative colitis). Taking melatonin daily in combination with conventional medication seems to help control a type of inflammatory bowel disease called ulcerative colitis.
  • Metabolic syndrome.
  • Osteoporosis.
  • Birth control.
  • Aging.
  • Other conditions.
More evidence is needed to rate melatonin for these uses.

Natural Medicines Comprehensive Database rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, and Insufficient Evidence to Rate (detailed description of each of the ratings).

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