What You Should Know about Melatonin Supplement

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Written by:


, Sleep Researcher
Last Updated: Thu, August 29, 2019
Fact checked by:

Marko Jevtic

, Sleep Specialist


Melatonin is a natural hormone that plays a crucial role in sleep. The synthesis and release of melatonin by the pineal gland in the brain are usually connected to the time of day. This means that when it is dark, the production and release of this hormone increases and it decreases when there is light. The production of this sleep hormone declines as we age. Melatonin is also synthetically produced in the laboratory as a supplement in the form of oral tablets. However, melatonin is also available in forms that can be put under the tongue or in the cheek, allowing the hormone to be absorbed directly into the body.

Some people tend to take melatonin orally so that they can adjust the internal clock of the body. This hormone supplement is used for insomnia, jet lag, helping blind individuals to establish a night and day cycle, and adjusting the sleep-wake cycles for people whose everyday work schedule changes or have shift-work disorder. Unlike other sleeping supplements or pills in the market, melatonin does not trigger dependency, and it does not have a hangover effect or a reduced response after continuous use.

Natural melatonin and synthetic melatonin

Melatonin is usually referred to as the darkness hormone. When it is produced by the brain, it indicates to the body that it is time to sleep or rest. Melatonin is naturally released by the pineal gland in the brain. When this hormone is released, it will bind to receptors that are responsible for the circadian rhythm. It then enters the cerebrospinal fluid and then finally gets into the bloodstream.

You can purchase natural or synthetic melatonin supplements in any pharmacy, health food stores, drug stores, or online around the globe without the need for a doctor’s prescription. Natural melatonin is extracted from the pineal glands of animals such as cows. On the other hand, synthetic melatonin supplements are developed in the laboratory. Natural and synthetic melatonin can be mixed or used together. This is because they both represent the same chemical formula of melatonin regardless of the production technique. This simply means that the desired effects would be the same whether you use synthetic or chemical melatonin supplements.

How does melatonin work?

The main job of the melatonin hormone in the body is regulating the night and day cycles or the sleep-wake cycles. Darkness triggers the human body to synthesize more melatonin that signals the body systems to prepare for sleep. Light tends to decrease the production of melatonin and it helps in signaling your body to prepare for being awake. Some individuals may experience trouble sleeping because they have a low concentration of melatonin in their body or the brain does not produce adequate amounts of this sleep hormone. By adding melatonin hormones through supplements, individuals experiencing sleep disorders can sleep without any problem.

When should you consider taking melatonin?

Melatonin is mainly the first drug of choice for individuals who are suffering from most sleeping problems. Because melatonin supplement is affordable and readily available over the counter, it is considered safe and is widely used all over the globe. Many people use melatonin supplements for jet lag, insomnia, and shift work.

Even though melatonin supplements are effective, they will not help every individual who suffers from a sleeping disorder. It is mainly effective for those who want to modify their circadian rhythm. Melatonin supplement will prove helpful for those who suffer from jetlag and can also help individuals to cope with their work shift schedule.

Is melatonin considered a drug?

According to the Food and Drug Administration (FDA), melatonin is categorized as a dietary supplement and it is not a regulated drug. This is the main reason why melatonin supplement is quite popular and it is readily available without a doctor’s prescription. However, since melatonin supplements are not regulated by the FDA, you may get insufficient or inaccurate information on the bottle label about its dosage and strength. Scientific studies show that 0.3mg of melatonin supplements is adequate to reestablish peaceful and quality sleep in adults. However, most pharmacies and stores will have even 5mg doses of melatonin hormone on their shelves.

Uses of melatonin

Treating sleep disorders

Melatonin is taken orally to help individuals who suffer from sleep conditions such as:

Other uses of melatonin

Apart from sleep disorders, melatonin can also help with other medical conditions. Some of these conditions include:


There is some evidence that the use of melatonin can help in relieving headaches. This is particularly true for cluster headaches that usually cause recurrent and severe pain on one side of the head and often in areas surrounding the eye. Research results show that using melatonin just before your bedtime can help in preventing episodic migraine headaches. When migraine headaches occur after the use of melatonin, they are usually milder and tend to pass more quickly. However, other pieces of evidence show that the use of melatonin will not reduce the frequency of the migraine attacks.

Gallbladder stones

Melatonin plays several roles in the gallbladder; for instance, the conversion of cholesterol into bile and assisting gallstones to move through the gallbladder. Free radical damage tends to increase the probability of gallstone development. The antioxidant properties of melatonin can be helpful in such cases.

Tinnitus or ringing in the ears

Scientific research shows that the effects associated with tinnitus tend to be slightly improved with the use of melatonin. This is mainly associated with its antioxidant properties and improved sleep. By taking melatonin at night, patients who experience tinnitus are assured of less ringing in the ears and better sleep quality.

Alzheimer’s disease

In all populations, the levels of melatonin will decrease significantly with age. However, this reduction is usually more pronounced in patients that suffer from Alzheimer’s disease. Research shows that melatonin slows down the cognitive decline that results due to Alzheimer’s disease.

Radioactivity protection

The damage that results from contact with radioactive substances occurs because of free radicals. Since melatonin has antioxidant properties, it is useful for individuals who work daily in high-radiation areas and those undergoing radiation therapy.

Endometriosis or painful uterus disorder

Research indicates that using melatonin daily for about 8 weeks will help reduce pain associated with endometriosis by about 39.9% and painkiller use by about 46%. It can also reduce pain during intercourse, menstruation, or when going to the bathroom.

Jet lag

Melatonin can help to improve some symptoms that are associated with jet lag, for example, movement coordination and alertness. Melatonin helps to slightly boost other symptoms of jet lag such as tiredness and daytime sleepiness. However, keep in mind that melatonin may not effectively shorten the time that it takes people with jet lag to fall asleep.

High blood pressure

Consuming a controlled-release form of melatonin just before bedtime can help to lower blood pressure in individuals who suffer from high blood pressure. The immediate-release formulation may not work when it comes to high blood pressure.

Protection against sunburns

Some people apply melatonin supplement directly on their skin before exposure to the sun to help protect them from sunburns.

Lower anxiety before surgery

Melatonin can be administered under the tongue or in the cheek to calm people before they receive anesthesia for surgery. It also seems to have fewer side effects in most people when compared to midazolam the conventional medicine that is usually used in such cases.

Eliminates withdrawal symptoms of smoking

Melatonin hormone can also be used to diminish the side effects that come about after one stops smoking. Consuming melatonin at least 3.5 hours after nicotine withdrawal helps in reducing symptoms such as restlessness, anxiety, and the cravings for cigarettes in smokers. This can be quite beneficial for individuals who want to quit smoking completely.

Melatonin and cancer

Some people use melatonin orally for brain cancer, breast cancer, prostate cancer, renal cancer, head cancer, gastrointestinal cancer, colon cancer, and neck cancer. Oral melatonin pills can help prevent the side effects that result from chemotherapy cancer treatment and radiation. This includes effects such as weight loss, mouth ulcers, weakness, nerve pain, and a reduction in thrombocytopenia or clot-forming cells. Clinical studies also imply that melatonin can work as an anticancer agent when used in conjunction with radiation therapy and chemotherapy. Studies show a substantial reduction in the risk of death, lower adverse events, and low costs that suggest that melatonin has great potential in the treatment of different types of cancer.

Safety of melatonin

Melatonin is safe for most adults and children when administered by mouth or injected into the body for a short period of time or when applied directly on the skin. Melatonin is also safe when injected into the body but under the supervision of a medical professional.

Melatonin is also considered safe when consumed orally long-term when compared to most sleeping pills. Melatonin has been used safely in most people for at least two years without experiencing major side effects. However, it can cause effects such as daytime sleepiness, headache, stomach cramps, irritability, and short-term feelings of depression. You should not use machinery or drive for at least five hours after taking melatonin.

Precautions when using melatonin

Melatonin and children

Melatonin supplements are considered safe for use by children when consumed as a single dose. However, it can be unsafe when given to children in multiple doses over a short period of time. This is because melatonin, being a hormone, can affect other hormones. As a result, it can interfere with development, particularly during adolescence.

Breastfeeding and pregnancy

Melatonin is unsafe when injected into the body or taken orally during pregnancy. Therefore, melatonin should not be used by pregnant mothers. Melatonin can also interfere with ovulation and make it more challenging for women to become pregnant. Therefore, if you are planning to have a baby, you should avoid the use of this supplement.

There is little evidence regarding the safety of melatonin in lactating mothers. Therefore, it is best to on avoid using melatonin when breastfeeding because its effects on the baby and mother are unknown.


Melatonin can worsen the symptoms associated with depression. Therefore, melatonin supplements should only be used by depression patients with prescription by a doctor or under close observation by a medical specialist.

Transplant recipients

Melatonin has been shown to boost the immune function, and this can interfere with the immunosuppressive therapy that is administered to people who are receiving transplants.

High blood pressure

Melatonin tends to raise blood pressure in individuals who are using specific medications for controlling blood pressure. Therefore, individuals who suffer from high blood pressure should avoid using melatonin.


Melatonin can boost blood sugar levels in diabetic patients. If you have diabetes and are using melatonin, it is important to carefully monitor your blood sugar levels.

Bleeding disorders

Melatonin can worsen bleeding in individuals with bleeding disorders. Furthermore, it may interfere with the function of some anticoagulant medication. Therefore, if you have any bleeding disorders, it is best to avoid using melatonin.

Seizure disorders

The use of melatonin can increase the risks of having seizures. Therefore, epileptic patients should avoid using melatonin.

Side effects of melatonin

Melatonin has fewer side effects when compared to other sleeping medications on the market, learn more about melatonin overdose. Several clinical trials have been carried out on the use of melatonin in low doses for short-term use and up to 3 months of usage. In most studies. no adverse events were found in the use of melatonin supplements. However, some of the common side effects of melatonin used include the following:

Common side effects

Less common side effects

The less common side effects of melatonin supplements include the following:

Some unwanted side effects on the elderly include:

NOTE: Since melatonin supplements are known to result in daytime drowsiness or sleepiness if using melatonin leaves you feeling drowsy, you should avoid operating machinery or driving at least five hours after taking this supplement. This will help prevent the occurrence of unexpected accidents.

The side effects associated with melatonin uses are not adverse. However, they will disappear when the user stops taking this supplement.

You should inform your doctor during regular health examinations if you are using melatonin supplements. You should also consult your physician if you are experiencing insomnia or trouble sleeping because it can be triggered by a medical problem.  

You should also consult your doctor to learn the correct melatonin dosage and determine whether melatonin is the perfect sleeping aid for you. This is important because the right dosage of this supplement will vary from one person to the other and the effects will also vary significantly.

Interaction of melatonin with other drugs

CNS depressants or sedative medications

Melatonin can cause drowsiness and sleepiness and should not be taken in combination with medications that trigger sleepiness, for example, sedatives. Using melatonin with sedative drugs can result in excessive sleepiness. Some of the sedatives that can interact with melatonin include phenobarbital, lorazepam, zolpidem, clonazepam, and many more.

Anticoagulant or antiplatelet drugs and melatonin

Anticoagulants and antiplatelet medications, supplements, and herbs help in reducing blood clotting. Melatonin should not be taken together with drugs that slow down blood clotting. This is because melatonin tends to slow blood clotting. When these drugs are taken together, it will increase the probability of bleeding and bruising. Some of the anticoagulants and antiplatelet drugs include aspirin, warfarin (Coumadin), heparin, enoxaparin (Lovenox), clopidogrel (Plavix), dalteparin (Fragmin), diclofenac (Voltaren), ibuprofen (Advil or Motrin), naproxen (Anaprox or Naprosyn), and many others.

Antidiabetes drugs and melatonin

Diabetes drugs work to lower the levels of blood sugar. On the other hand, melatonin can trigger an increase in the blood sugar levels. By increasing the blood sugar levels in the body, melatonin tends to decrease the effectiveness of anti-diabetes drugs. Therefore, if you are using melatonin and diabetes drugs, then the dosage of your diabetes drugs should be changed to guarantee their effectiveness. Some diabetes drugs that can interact with melatonin include pioglitazone (Actos), glipizide (Glucotrol), insulin, tolbutamide (Orinase), Micronase), glimepiride (Amaryl), rosiglitazone (Avandia), glyburide (DiaBeta, Glynase PresTab, chlorpropamide (Diabinese), and many others.

Contraceptive drugs or birth control pills

The human body naturally produces melatonin hormone. Contraceptive drugs tend to increase the amount of melatonin that the body makes. This means that taking melatonin together with birth control pills can result in higher levels of melatonin in the body. This will, in turn, increase the effects and the resulting side effects associated with melatonin. Some birth control drugs that can interact with melatonin include ethinyl estradiol, levonorgestrel (Triphasil), norethindrone, ethinyl estradiol and many more.

Immunosuppressant drugs and melatonin

Melatonin can increase the functions of the immune system and this will interfere with immunosuppressive therapy. By consuming melatonin together with immunosuppressant medications, the effectiveness of these drugs can be affected. This means that the immune system functions will not be decreased but enhanced. Some of the drugs that reduce the immune system functions include corticosteroids (glucocorticoids), prednisone (Deltasone or Orasone), azathioprine (Imuran), daclizumab (Zenapax), Orthoclone OKT3), cyclosporine (Neoral, basiliximab (Simulect), Sandimmune), sirolimus (Rapamune), tacrolimus (FK506, Prograf), muromonab-CD3 (OKT3, mycophenolate (CellCept), and many others.

Flumazenil (Romazicon) and melatonin

Flumazenil (Romazicon) tends to decrease the effects of melatonin. However, it is not clear how the interaction between these two drugs occur. Taking (Romazicon) together with melatonin can decrease the effectiveness and efficiency of melatonin supplements.

Benzodiazepines or sedative medications and melatonin

Benzodiazepines are drugs that cause drowsiness or sleepiness and they are used for managing sleep disorders such as insomnia. Since melatonin is a sleep supplement, taking it together with sedative drugs can result in too much sleep. Some sedatives that can react with melatonin include diazepam (Valium), clonazepam (Klonopin), lorazepam (Ativan), and many more.

Verapamil and melatonin

Verapamil (Calan, Verelan, Isoptin, Covera) tends to interact with melatonin. The body will get rid of melatonin by breaking it down. Verapamil will increase the speed at which the body gets rid of melatonin supplements. Therefore, by consuming melatonin supplements together with verapamil, it can decrease the effectiveness of the melatonin supplements.

Melatonin and fluvoxamine (Luvox)

Fluvoxamine is a selective serotonin reuptake inhibitor. Fluvoxamine can increase the amounts of melatonin supplements that are absorbed by the body. This means that this drug combination can result in an increase in the side effects and the desired effects of melatonin supplements. Increased levels of melatonin can result in unwanted excessive drowsiness.

Caffeine and melatonin

Caffeine can decrease the levels of melatonin in the body. In addition, the use of caffeine along with melatonin can result in the decrease in the effectiveness of melatonin supplements.

Nifedipine GITS (Procardia XL) and melatonin

Nifedipine GITS (Procardia XL) is a drug that is used in lowering blood pressure. Using melatonin together with nifedipine GITS can result in a decrease in the effectiveness of nifedipine GITS. Because of this interaction, the blood pressure will not be reduced. Patients who are using Nifedipine GITS should consult their doctor before they used melatonin supplements.

Recommended melatonin dosage

By mouth or oral dosage for adults


Primary insomnia – It is recommended that adults take 2-3mg of melatonin supplements before bedtime for at least 29 weeks. Higher doses of 12mg every day have been used for short time durations of up to 4 weeks.

Secondary insomnia – 2-12mg should be used for at least 4 weeks. Lower doses of melatonin can be used for up to 24 weeks for managing secondary insomnia.

IV or intravenous application

Melatonin can be administered into the vein for treatment of solid tumors together with conventional therapy such as radiation therapy and chemotherapy. Usually, 20mg of melatonin supplement is administered every day intravenously for 2 months. This is then followed by 10 mg of melatonin supplement given orally.

Application on the skin

For sunburns, a gel that contains 0.05-2.5% of melatonin is applied on the skin at least 15 minutes before sun exposure or not more than 4 hours after exposure to the sun.

Sublingual or under-the-tongue application

To help reduce anxiety before surgery, 5mg or 0.05 to 0.2mg per kg of body weight should be administered about 90-100 minutes before using anesthesia.

Melatonin dosage for children

Insomnia in children

Primary insomnia – 5 mg or 0.05 to 0.015 mg per kg of body weight should be taken just before bedtime for 4 weeks. This dosage is ideal for primary insomnia in children between 6 to 12 years old.

Secondary insomnia – 6-9mg of melatonin supplements should be taken orally before bedtime for at least 4 weeks. This dosage can be used in children between 3 and 12 years.

Boosting the chances of success when using melatonin supplement

Melatonin is not a cure for all your sleep problems. For you to get a good sleep at night, you will have to follow healthy sleeping habits. You need to avoid using tech devices such as your phone for at least an hour before your bedtime. You should also wind down in the evening with a bedtime ritual or relaxing activity.

Even though melatonin can help in treating occasional insomnia, it is still unclear whether its long-term use is safe. If you find yourself relying on melatonin supplement every night, you should consult your physician so that you can create a better treatment approach that will ensure quality sleep.

Avoid going overboard

You do not have to consume huge doses of melatonin to get the desired effects. It is recommended that you use one to 3mg of melatonin supplements.

Timing is crucial

It is best that you take melatonin supplements at least one or two hours before your bedtime. For individuals who are taking melatonin supplements to prevent jet lag, it is best that they start using it a few days before your actual time-zone bedtime.

Watch out for any side effects

Even though melatonin supplements are generally safe to use, they may trigger some side effects like nausea, dizziness, and headache. However, it can also cause drowsiness and this is why you need to wait for at least five hours after using melatonin before you operate machinery or drive.


Melatonin hormone has many functions in the human body, some of which are yet to be understood. With the continuous scientific research carried out, the full potential of melatonin hormone within the pharmaceutical field will become clearer. Individuals who want to use melatonin supplements should consider consulting a physician before commencing therapy. This is especially important for children and adults or the elderly who suffer from different medical conditions or autoimmune disorders. Furthermore, melatonin supplements should be purchased from reliable and trustworthy providers and pharmacists. Dietary supplements are not regulated by the FDA and you need to be confident that you are buying the best melatonin supplements on the market.

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