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, a disorder that causes a strong urge to move ones legs (restless legs syndrome; RLS), 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.
How it works
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.
Likely EffectiveSleep disorders in blind people
Taking melatonin by mouth helps improve sleep disorders in blind children and adults.
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.
Melatonin is LIKELY SAFE for most adults when taken by mouth or injected into the body in the short-term, or when applied to the skin
Melatonin is POSSIBLY SAFE when used by mouth appropriately, long-term. Melatonin has been used safely for up to 2 years in some people. However, it can cause some side effects including headache, short-term feelings of depression, daytime sleepiness, dizziness, stomach cramps, and irritability. Do not drive or use machinery for four to five hours after taking melatonin.
Pregnancy and breast-feeding: Melatonin isPOSSIBLY UNSAFEwhen taken by mouth or injected into the body during pregnancy. Do not use it. Melatonin might also interfere withovulation, making it more difficult to becomepregnant.
Not enough is known about the safety of using melatonin when breast-feeding. It is best not to use it.
Children: Melatonin is POSSIBLY SAFE when taken by mouth as a single dose. It is POSSIBLY UNSAFE when taken by mouth or injected into the body in multiple doses in the short-term. Because of its effects on other hormones, melatonin might interfere with development during adolescence.
Bleeding disorders: Melatonin might make bleeding worse in people with bleeding disorders.
Depression: Melatonin can make symptoms of depression worse.
Diabetes: Melatonin might increase blood sugar in people with diabetes. Monitor your blood sugar carefully, if you have diabetes and take melatonin.
High blood pressure: Melatonin can raise blood pressure in people who are taking certain medications to control blood pressure. Avoid using it.
Seizure disorders: Using melatonin might increase the risk of having a seizure.
Transplant recipients: Melatonin can increase immune function and might interfere with immunosuppressive therapy used by people receiving transplants.
The body makes melatonin. Birth control pills seem to increase how much melatonin the body makes. Taking melatonin along with birth control pills might cause too much melatonin to be in the body.Some birth control pills include ethinyl estradiol and levonorgestrel (Triphasil), ethinyl estradiol and norethindrone (Ortho-Novum 1/35, Ortho-Novum 7/7/7), and others.Caffeine might increase or decrease melatonin levels in the body. When taken together with melatonin supplements, caffeine seems to increase melatonin levels.Fluvoxamine (Luvox)
Taking fluvoxamine (Luvox) can increase the amount of melatonin that the body absorbs. Taking melatonin along with fluvoxamine (Luvox) might increase the effects and side effects of melatonin.Methamphetamine
Some medications are changed and broken down by the liver. Melatonin might decrease how quickly the liver breaks down some medications. Taking melatonin along with some medications that are broken down by the liver can increase the effects and side effects of some medications. Before taking melatonin, talk to your healthcare provider if you are taking any medications that are changed by the liver.Some medications changed by the liver include acetaminophen (Tylenol), amitriptyline (Elavil), clopidogrel (Plavix), clozapine (Clozaril), diazepam (Valium), estradiol, olanzapine (Zyprexa), ondansetron (Zofran), propranolol (Inderal), ropinirole (Requip), tacrine (Cognex), theophylline, verapamil (Calan, Covera-HS, Isoptin, Verelan), warfarin (Coumadin), and others.Some medications are changed and broken down by the liver. Melatonin might decrease how quickly the liver breaks down some medications. Taking melatonin along with some medications that are broken down by the liver can increase the effects and side effects of some medications. Before taking melatonin, talk to your healthcare provider if you are taking any medications that are changed by the liver.Some medications changed by the liver include amitriptyline (Elavil), carisoprodol (Soma), citalopram (Celexa), diazepam (Valium), lansoprazole (Prevacid), omeprazole (Prilosec), phenytoin (Dilantin), warfarin, and many others.There is some concern that melatonin might increase or decrease blood sugar. Diabetes medications are used to lower blood sugar. By affecting blood sugar, melatonin might decrease or increase the effectiveness of diabetes medications. Monitor your blood sugar closely. The dose of your diabetes medication might need to be changed.Some medications used for diabetes include glimepiride (Amaryl), glyburide (DiaBeta, Glynase PresTab, Micronase), insulin, pioglitazone (Actos), rosiglitazone (Avandia), chlorpropamide (Diabinese), glipizide (Glucotrol), tolbutamide (Orinase), and others.Melatonin might decrease blood pressure in healthy people. However, melatonin might make blood pressure worse in people who are already taking medications for high blood pressure. Do not take too much melatonin if you are taking medications for high blood pressure.Some medications for high blood pressure include captopril (Capoten), enalapril (Vasotec), losartan (Cozaar), valsartan (Diovan), diltiazem (Cardizem), Amlodipine (Norvasc), hydrochlorothiazide (HydroDiuril), furosemide (Lasix), and many others.Melatonin might increase the immune system. Taking melatonin along with medications that decrease the immune system might decrease the effectiveness of medications that decrease the immune system.Some medications that decrease the immune system include azathioprine (Imuran), basiliximab (Simulect), cyclosporine (Neoral, Sandimmune), daclizumab (Zenapax), muromonab-CD3 (OKT3, Orthoclone OKT3), mycophenolate (CellCept), tacrolimus (FK506, Prograf), sirolimus (Rapamune), prednisone (Deltasone, Orasone), corticosteroids (glucocorticoids), and others.Melatonin might increase the frequency of seizures in some people, particularly children. Taking melatonin with drugs that lower the seizure threshold might increase the risk of a seizure.Some medications that lower seizure threshold include anesthetics (propofol, others), antiarrhythmics (mexiletine), antibiotics (amphotericin, penicillin, cephalosporins, imipenem), antidepressants (bupropion, others), antihistamines (cyproheptadine, others), immunosuppressants (cyclosporine), narcotics (fentanyl, others), stimulants (methylphenidate), theophylline, and others.Melatonin might slow blood clotting. Taking melatonin along with medications that also slow clotting might increase the chances of bruising and bleeding.Some medications that slow blood clotting include aspirin, clopidogrel (Plavix), diclofenac (Voltaren, Cataflam, others), ibuprofen (Advil, Motrin, others), naproxen (Anaprox, Naprosyn, others), dalteparin (Fragmin), enoxaparin (Lovenox), heparin, warfarin (Coumadin), and others.Melatonin might increase the frequency of seizures in some people, particularly children with multiple neurological disorders. In theory, taking melatonin might decrease the effectiveness of medications used to prevent seizures.Some medications used to prevent seizures include phenobarbital, primidone (Mysoline), valproic acid (Depakene), gabapentin (Neurontin), carbamazepine (Tegretol), phenytoin (Dilantin), and others.Taking melatonin with methamphetamine might increase the effects and side effects of methamphetamine.Nifedipine GITS (Procardia XL)
Nifedipine GITS (Procardia XL) is used to lower blood pressure. Taking melatonin might decrease the effectiveness of nifedipine GITS for lowering blood pressure.Verapamil (Calan, Covera, Isoptin, Verelan)
Melatonin might cause sleepiness and drowsiness. Drugs that cause sleepiness and drowsiness are called sedatives. Taking melatonin along with sedative medications might cause too much sleepiness.Some of these sedative medications include clonazepam (Klonopin), diazepam (Valium), lorazepam (Ativan), and others.Melatonin might cause sleepiness and drowsiness. Medications that cause sleepiness are called sedatives. Taking melatonin along with sedative medications might cause too much sleepiness.Some sedative medications include clonazepam (Klonopin), lorazepam (Ativan), phenobarbital (Donnatal), zolpidem (Ambien), and others.The body breaks down melatonin to get rid of it. Verapamil (Calan, Covera, Isoptin, Verelan) can increase how quickly the body gets rid of melatonin. Taking melatonin along with verapamil (Calan, Covera, Isoptin, Verelan) might decrease the effectiveness of melatonin.Warfarin (Coumadin)
Warfarin (Coumadin) is used to slow blood clotting. Melatonin might increase the effectiveness of warfarin (Coumadin). Taking melatonin along with warfarin (Coumadin) might increase the chances of bruising and bleeding. Be sure to have your blood checked regularly. The dose of your warfarin (Coumadin) might need to be changed.