Some people take melatonin by mouth to adjust the body’s internal clock. Melatonin is most commonly used for insomnia and improving sleep in different conditions. For example, it is used for jet lag, for adjusting sleep-wake cycles in people whose daily work schedule changes (shift-work disorder), and for helping people establish a day and night cycle.
Coronavirus disease 2019 (COVID-19): There is no good evidence to support using melatonin for COVID-19. Follow healthy lifestyle choices and proven prevention methods instead.
How does it work ?
Uses & Effectiveness
Likely Effective for
- Trouble falling asleep at a conventional bedtime (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.
- Non-24-hour sleep wake disorder. Taking melatonin at bedtime seems to improve sleep in children and adults who are blind.
Possibly Effective for
- Sleep disturbance caused by certain blood pressure medicine (beta blocker-induced insomnia). 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 shows that taking a melatonin supplement might reduce problems sleeping in patients taking beta-blocker drugs.
- Cancer. High doses of melatonin, administered by a healthcare professional along with chemotherapy or other cancer treatments, might reduce tumor size and improve survival rates in some people with cancer.
- A painful uterine disorder (endometriosis). Taking melatonin daily for 8 weeks seems to reduce pain and painkiller use in women with endometriosis. 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. Taking melatonin short-term seems to shorten the amount of time it takes to fall asleep in people with insomnia, but only by about 7-12 minutes. Melatonin might also increase the amount of time that a person with insomnia spends sleeping. But results are conflicting, and any benefit is small at best. 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 also interest using melatonin for people with insomnia and other conditions. Research shows that melatonin might improve sleeping trouble related to conditions such as depression, schizophrenia, epilepsy, autism, developmental disabilities, and intellectual disabilities. But it’s unclear if melatonin improves sleep problems in people with Alzheimer disease, dementia, Parkinson disease, traumatic brain injury, substance use disorders, or in people undergoing dialysis.
- 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.
- Migraine. Most evidence shows that taking melatonin before bed can prevent migraines in adults and children. When headaches do occur, they are milder and pass more quickly. It is not clear if melatonin helps to treat migraines.
- Anxiety before surgery. Melatonin used under the tongue or by mouth modestly reduces anxiety before surgery in adults. It also seems to have fewer side effects than some other medications used to reduce anxiety before surgery. It is unclear if melatonin is beneficial for reducing anxiety before surgery in children.
- Sunburn. Applying melatonin gel to the skin before sun exposure seems to prevent sunburn. Applying melatonin cream to the skin before sun exposure seems to help people that are very sensitive to sunlight. But melatonin cream might not prevent sunburn in people with less sensitive skin.
- A group of painful conditions that affect the jaw joint and muscle (temporomandibular disorders or TMD). Research suggests that taking melatonin at bedtime for 4 weeks reduces pain by 44% and increases tolerance to pain by 39% in women with jaw pain.
- Low levels of platelets in the blood (thrombocytopenia). Taking melatonin by mouth can improve low blood platelet counts associated with cancer, cancer treatment, and other disorders.
Possibly Ineffective for
- Athletic performance. Taking melatonin shortly before resistance exercise or cycling doesn’t appear to improve performance.
- Involuntary weight loss in people who are very ill (cachexia or wasting syndrome). Research shows that taking melatonin each evening for 28 days does not improve appetite, body weight, or body composition in people with wasting syndrome from cancer.
- Diseases, such as Alzheimer disease, that interfere with thinking (dementia). Most research shows that taking melatonin does not improve behavior or affect symptoms in people with Alzheimer 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.
- Inability to become pregnant within a year of trying to conceive (infertility). Taking melatonin does not appear to improve pregnancy rates in women undergoing fertility treatments.
- Sleep disorder due to rotating or night shifts (shift work disorder). Taking melatonin by mouth does not seem to improve sleeping problems in people who do shift work.
Likely InEffective for
- Withdrawal from drugs called benzodiazepines. Some people take benzodiazepines for sleep problems. Long-term use can lead to dependence. Taking melatonin at bedtime doesn’t help people stop taking these drugs.
- 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 for
- An eye disease that leads to vision loss in older adults (age-related macular degeneration or AMD). Early research shows that taking melatonin might delay the loss of vision in people with age-related vision loss.
- Eczema (atopic dermatitis). Early research shows that melatonin can reduce the symptoms of eczema in children. However, although melatonin improves sleep quality it does not always can shorten the time it takes for these children to fall asleep.
- Attention deficit-hyperactivity disorder (ADHD). Limited research shows that melatonin might reduce insomnia in children with ADHD who are taking stimulants. But improved sleep doesn’t seem to decrease symptoms of ADHD.
- Autism. Early research shows that taking melatonin may improve aggression or impulsiveness in kids with autism. But taking melatonin doesn’t seem to improve other behaviors.
- Enlarged prostate (benign prostatic hyperplasia or BPH). Taking melatonin may reduce excessive urination at night in some men with enlarged prostate. But it’s not clear if this improvement is clinically meaningful.
- Bipolar disorder. Early research shows 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.
- Tiredness in people with cancer. Taking melatonin short-term doesn’t seem to improve tiredness or quality of life in people with cancer. It’s unclear if it would be beneficial if used for a longer time.
- Chronic fatigue syndrome (CFS). Some early research shows that taking melatonin in the evening might improve some symptoms of CFS, including fatigue, concentration, and motivation. However, other early research shows that taking melatonin by mouth does not improve CFS symptoms.
- A lung disease that makes it harder to breathe (chronic obstructive pulmonary disease or COPD). Some evidence shows 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.
- A mental state in which a person is confused and unable to think clearly. It is unclear if oral melatonin helps to prevent delirium in adults who are in the hospital.
- Diabetes. Although some research shows that melatonin might reduce levels of blood sugar, it isn’t known if this is helpful for patients with diabetes.
- Dry mouth. Taking melatonin by mouth and using melatonin as a mouth rinse doesn’t prevent dry mouth in people with head and neck cancer being treated with cancer drugs and radiation. But it might delay the start of symptoms.
- Indigestion (dyspepsia). Taking melatonin nightly might reduce indigestion in some people. But it doesn’t seem to work as well in people with prior H. pylori infection.
- Side effects in people with a breathing tube. Taking melatonin might reduce some side effects from having a breathing tube.
- Confusion and agitation after surgery. Early research in children shows that taking melatonin might help to reduce the amount of agitation caused by a certain type of anesthesia, called sevoflurane.
- Seizure disorder (epilepsy). There is some evidence that taking melatonin at bedtime may reduce seizures in children and adults with epilepsy. But higher quality research is needed to confirm.
- Fibromyalgia. Melatonin might decrease the severity of pain and stiffness in people with fibromyalgia.
- Persistent heartburn. Taking melatonin daily at bedtime might improve symptoms of acid reflux, including heartburn. However, taking conventional medication seems to be more effective.
- A digestive tract infection that can lead to ulcers (Helicobacter pylori or H. pylori). Evidence shows that taking melatonin together with the drug omeprazole improves healing in people with ulcers caused by H. pylori infection.
- A long-term disorder of the large intestines that causes stomach pain (irritable bowel syndrome or IBS). Early research shows that taking melatonin might improve some, but not all, symptoms of IBS. Some research shows that melatonin works better in people with IBS in which constipation is the main symptom.
- Kidney transplant. Early research shows that taking melatonin does not improve how well the kidney works after a kidney transplant.
- Symptoms of menopause. Limited research shows that melatonin does not relieve menopausal symptoms. However, taking melatonin in combination with soy isoflavones might help psychological symptoms associated with menopause.
- A grouping of symptoms that increase the risk of diabetes, heart disease, and stroke (metabolic syndrome). Early research shows that taking melatonin reduces blood pressure as well as low-density lipoprotein (LDL or “bad”) cholesterol in people with metabolic syndrome.
- Multiple sclerosis (MS). Early research shows that taking melatonin doesn’t improve MS symptoms such as fatigue and disability.
- Heart attack. Early research shows that melatonin injected directly into the vein within 2.5 hours after a heart attack, might decrease damage to the heart.
- Brain damage in infants caused by lack of oxygen. Early research shows that giving melatonin in addition to cooling-therapy might improve outcomes in infants with brain damage caused by a lack of oxygen. It is unclear if melatonin helps to prevent death in these infants.
- Injury to the brain, spine, or nerves (neurological trauma). Early research shows that taking melatonin does not improve symptoms in children that have had a concussion.
- Bed-wetting. Early research shows that taking melatonin before bed does not change how often children wet their beds at nighttime.
- Build up of fat in the liver in people who drink little or no alcohol (nonalcoholic fatty liver disease or NAFLD). Some evidence shows that taking melatonin improves markers of liver function in people with NAFLD. But not all research agrees.
- Swelling (inflammation) and build up of fat in the liver in people who drink little or no alcohol (nonalcoholic steatohepatitis or NASH). Some evidence shows that taking melatonin improves markers of liver function in the blood of people with nonalcoholic steatohepatitis.
- Swelling (inflammation) and sores inside the mouth (oral mucositis). Taking melatonin by mouth and using melatonin as a mouth rinse seems to delay mouth ulcers from forming in people getting cancer drugs and radiation. But it might not reduce the number of these people who get mouth ulcers.
- Low bone mass (osteopenia). Early research in women with low bone mass after menopause suggests that taking melatonin slightly increases bone thickness in the spine and shin but not in other areas.
- Chronic pain. Limited research suggests that taking melatonin might improve different types of chronic pain by a small amount.
- A hormonal disorder that causes enlarged ovaries with cysts (polycystic ovary syndrome or PCOS). Melatonin might improve irregular menstruation in women with PCOS. Taking melatonin seems to increase the number of menstrual cycles over 6 months from 2.5 to 4.
- Pain after surgery. Some research shows that taking melatonin for 2 days and continuing for up to 3 weeks when undergoing surgery might reduce pain and use of pain medication.
- Recovery after surgery. Some evidence shows 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 shows 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 symptoms.
- A pregnancy complication marked by high blood pressure and protein in the urine (pre-eclampsia). Taking melatonin with vitamin B6 might sometimes reduce the need for blood pressure medicines. But it doesn’t seem to improve pre-eclampsia overall.
- Prostate cancer. Taking melatonin by mouth together with conventional medications might reduce the growth of prostate cancer.
- Itching. Taking melatonin by mouth might reduce itching in people with kidney failure who are on dialysis.
- Skin damage caused by radiation therapy (radiation dermatitis). In women with breast cancer, applying a specific melatonin emulsion cream to the skin during radiation treatment seems to reduce radiation dermatitis.
- A sleep disorder in which people act out dreams while sleeping. Some evidence shows that taking melatonin before bed reduces muscle movement during sleep in people with a sleep disorder that involves acting out dreams.
- A disorder that causes leg discomfort and an irresistible urge to move the legs (restless legs syndrome or RLS). Early research shows that taking melatonin before bedtime might make symptoms worse in people with restless legs syndrome.
- A disease that causes swelling (inflammation) in body organs, usually the lungs or lymph nodes (sarcoidosis). Early evidence shows 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 shows that it might not have any benefits and might worsen the side effects of second-generation antipsychotic medications.
- Seasonal depression (seasonal affective disorder or SAD). Some early research shows 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.
- Quitting smoking. Taking melatonin 3.5 hours after quitting smoking seems to reduce anxiety, restlessness, and cigarette cravings.
- Blood infection (sepsis). There is conflicting research about the effect of melatonin on sepsis in neonates. While some early research shows that giving melatonin in addition to antibiotics improves severity of blood infection, other research shows that melatonin has no effect.
- Stress. There is some evidence that taking melatonin might improve memory while under stress.
- A movement disorder often caused by antipsychotic drugs (tardive dyskinesia). Some evidence shows that taking melatonin by mouth decreases symptoms of a movement disorder called tardive dyskinesia. However, other evidence shows that taking melatonin daily does not reduce involuntary movements in these patients.
- Ringing in the ears (tinnitus). Some evidence shows that taking melatonin at night reduces ringing in the ears and improves sleep quality. However, other research shows that it does not reduce ear ringing.
- Tension headache. It is unclear if melatonin is beneficial for reducing tension headaches.
- A type of 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.
- Birth control.
- Problems with mental function.
- Other conditions.
More evidence is needed to rate melatonin for these uses.
When applied to the skin: Melatonin is LIKELY SAFE for most adults when applied directly to the skin short-term.
When given by IV: Melatonin is POSSIBLY SAFE when injected directly into the body under the supervision of a health care professional.
Special Precautions and Warnings
Breast-feeding: 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, short-term. Melatonin is usually well tolerated when taken in doses up to 3 mg per day in children and 5 mg per day in adolescents. There is some concern that melatonin might interfere with development during adolescence. While this still needs to be confirmed, melatonin should be reserved for children with a medical need. There isn’t enough evidence to know if melatonin is safe in children when taken by mouth, long-term.
Bleeding disorders: Melatonin might make bleeding worse in people with bleeding disorders.
Depression: Melatonin can make symptoms of depression worse.
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.