Melatonin is a hormone secreted in our body and performs certain functions as a natural sleep aid. It is present in some foods from where we get it. It is also manufactured as oral pills, in liquid form, and as lozenges.

We show in our post here,

  • how it works as a hormone,
  • its functions, and its benefits
  • In which foods is it naturally present?
  • In what forms is melatonin present as a supplement?
  • What are the supplements used for?
  • What are the side effects and contraindications?
  • What is the dosage?
  • What happens if more of it is taken?
  • Its use in children
  • Interaction with other drugs

What is melatonin hormone and how does it work?

Melatonin is a naturally occurring hormone in the body, which is secreted by the pineal gland of the brain. It is called the “hormone of darkness” because it is secreted during the dark hours of the day to help us sleep and maintain the circadian rhythm of the body.

The circadian rhythm is the internal biological clock of the body, which induces sleep during the night and wakefulness during the day.

The pineal gland in response to darkness secretes melatonin hormone at around 9 p.m. Its levels in the blood rise sharply and you begin to feel drowsy.

The levels stay high throughout the night and as daybreak sets in, the levels begin to fall. They attain low daytime levels at about 9 a.m. These levels can barely be detected.

Bright light whether natural or artificial inhibits the release of melatonin hormone. It is necessary for darkness to be present for this hormone to be secreted. That is why it is also referred to as the “Dracula of hormones”. 

Functions and benefits of the melatonin hormone

As mentioned above, melatonin is a naturally occurring hormone secreted by the pineal gland in the brain. It serves the following functions in the body.

  • It helps maintain the circadian rhythm of the body. Its secretion during the night occurs at around 9 p.m. and helps to induce sleep.
  • This hormone regulates the female reproductive hormones, which determine the onset of menstruation, its frequency, its duration, and the onset of menopause.
  • It is a strong antioxidant that helps to strengthen the immune system of the body.
  • Some researchers believe that melatonin is related to the aging process because its night-time levels are higher in younger people than in the elderly. Its levels are highest at the age of 20 years and fall to 20% by the age of 80 years. This could also be the reason why some older people sleep for lesser hours than when they were young.

Foods that contain melatonin

Melatonin is naturally present in some foods.

Eggs and fish are higher melatonin-containing food groups in animal foods, whereas, among plant foods, most nuts have a good amount of melatonin. Pistachios and almonds are among the highest.

Some kinds of mushrooms, cereals, and germinated legumes or seeds are also good dietary sources of melatonin.

Other foods with good melatonin content include:

  • Fruits and vegetables (tart cherries, asparagus, tomatoes, pomegranate, corn, grapes, broccoli, olives cucumber)
  • Grains (rice, barley,)
  • Nuts and Seeds (walnuts, peanuts, mustard seeds, flaxseed, sunflower seeds)

Melatonin supplements for sleep 

Melatonin is also made synthetically in the laboratory. Its supplements are available as oral pills, in liquid form, and as sublingual lozenges that you can place under the tongue.

It is taken as a sleep aid, which helps you fall asleep more quickly and increases your sleep hours.

Melatonin is the only hormone pill in the United States that is available in medical stores without a prescription. It is considered a supplement because it is present in many foods.

You take it to induce sleep and adjust the biological clock of the body whenever it has been disturbed such as due to jet lag or changing working shifts.

It is usually advised to be taken 2 to 4 hours before bedtime. It not only induces sleep but also increases your sleep hours.

Most sleep experts do not advise the use of melatonin for more than two weeks. Any longer need of use requires that your sleep disorder be investigated

Melatonin is an over-the-counter (OTC) natural sleep aid and is available in health stores, drug stores, and department stores. You do not need a prescription to buy its supplements.


Melatonin supplements are used for the following conditions:

  • Insomnia due to jet lag, changing shifts at work, old age and to treat insomnia due to sleep disorders, which upset the circadian rhythm of the body.
  • For general improvement of sleep in healthy adults to induce sleep and increase sleep hours.
  •  In withdrawal syndrome caused by stopping benzodiazepines, which were being taken to promote sleep.
  • To increase the effectiveness of cancer therapies. This use still requires thorough evidence.
  • For sunburn, melatonin can be used alone or in combination with vitamin E.
  • In irritable bowel syndrome, it helps to reduce the symptom of abdominal pain.
  • In epilepsy, studies indicate that the frequency of seizures was reduced but this study still requires more evidence.

Side effects

Melatonin supplements are advised to be taken in low doses for short-term up to three months. At such doses, the side effects are very few and minor.

Its adverse effects (with long-term use) are mentioned below and you should contact your doctor if you experience any of these, because changes in its dosage or stopping it may be necessary.

  • Headache
  • Irritability
  • Dizziness,
  • Tremors
  • Abdominal cramps.
  • Drowsiness during the next day
  • Mood changes such as in depression
  • Grogginess and confusion during the next day
  • Allergic reactions especially of the mouth, tongue, and throat such as itching and swelling
  • Vivid dreams
  • Enlarged breasts in men (called gynecomastia) and decreased libido.
  • It can interfere with fertility in women.


If you have any of the following conditions, you must consult your doctor before starting melatonin supplements.

  • Allergy – Stop it if you develop an allergy to it.
  • Diabetes – Melatonin can increase your blood sugar.
  • High blood pressure – It can also increase your blood pressure.
  • Liver disease
  • Immune disorders – Its effects on patients with autoimmune disorders such as multiple sclerosis, psoriasis, Crohn’s disease, lupus, and rheumatoid arthritis is not known.
  • Depression – Melatonin can worsen the symptoms of depression.
  • Epilepsy – The risk of seizures can increase with melatonin.
  • Pregnancy – The safety of use during pregnancy is not established.
  • Lactation
  • Melatonin and Alcohol. You should avoid alcohol when on these supplements because alcohol is a nervous stimulant in smaller doses but depresses the nervous system later. This causes a disturbance in sleep patterns.

Melatonin and children

You should avoid giving melatonin supplements to children because of its effects on hormones, which can disturb development during adolescence.

As it is, the brain of a normal and healthy child produces significant amounts of melatonin, and the effects of giving extra amounts on development are still not fully understood.

Some data exist that melatonin may be helpful to induce sleep in children with developmental problems as in acoustic children, children with cerebral palsy, and mental retardation.

Sleeplessness in children should be treated by following proper sleep hygiene measures first and if sleeping problems persist, advice should be taken from a sleep specialist.

Drug interactions

Melatonin should not be taken with the following medications.

  • Sedatives such as clonazepam (Klonopin), lorazepam (Ativan), phenobarbital (Donnatal), zolpidem (Ambien), and others taken with melatonin can cause too much sleepiness.
  • Birth control pills increase melatonin production in the body. Therefore, they can increase the levels of melatonin in the body.
  • Taking caffeine along with it decreases its effectiveness because caffeine decreases its levels.
  • Antidiabetic medicines. Melatonin increases blood sugar and therefore, reduces the effectiveness of these medications.
  • Immunosuppressants suppress the immune system and melatonin increases the immune system. The two, therefore, should not be taken together as the efficacy of the suppressants will be reduced.
  • Blood thinners such as warfarin should not be combined with melatonin as blood-clotting time is considerably reduced and can cause bleeding.
  • Antidepressants
  • Corticosteroids
  • Benzodiazepines such valium
  • St. John’s Wort


Male adults need 150 micrograms while female adults need 100 micrograms. Tablets with these strengths may not be available and you may, therefore, have to break them up to get the required strength of dose.

The most commonly available melatonin tablets are 3 mg strength,1 mg, 5 mg, and 10 mg tablets.

Taking larger doses will be counterproductive. Too much melatonin will disturb your sleep cycle and will cause headaches, nausea, dizziness, and irritability.

It is important to note that you should not beak a time-release pill as it will destroy the time-release mechanism.