Melatonin: 6 Health Benefits, Dosing & How It Works

Updated in November 2023

Melatonin is a hormone that is naturally produced by the body. Its main function is to regulate the normal circadian rhythm, but it also promotes good overall body function and serves as an antioxidant. 

This hormone is produced in the pineal gland, which becomes active when we do not have any light stimulation. It is common for melatonin to only be produced at night to induce sleep. For this reason, it is important to decrease any light sources, stimulating soundsor smells that can trigger your metabolism and decrease the production of melatonin. Generally, the production of melatonin reduces with age, and therefore, nightmares are very common in older adults.

Although it is naturally produced in the body, you can also take melatonin through supplements or medication, and it can even be found as a compound in some foods. You should always take melatonin under medical supervision.

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What you can take it for

Melatonin is a hormone that has many health benefits, such as:

1. Improving sleep quality

Many studies show that melatonin can positively impact sleep quality and can treat insomnia by increasing total sleep time and reducing the time it takes to fall asleep. It can be used in children and adults.

2. Strengthening the immune system

Due to its antioxidant effect, melatonin has been shown to help strengthen the immune system. It can help to prevent various diseases, especially virus infections.

3. Protecting the nervous system

As a powerful antioxidants, melatonin helps to protect the nervous system from neuron breakdown. For this reason, melatonin can be indicated as an aid for the treatment of conditions such as glaucoma, retinopathy, macular degeneration, migraine, fibromyalgia, Alzheimer's or ischemia.

4. Improving seasonal depression

Seasonal affective disorder is a type of disorder that occurs during the winter that triggers symptoms like sadness, excess drowsiness, increased appetite and difficulty concentrating.

This disorder happens more frequently in people who live in regions where winter lasts for a long time. It is associated with a decreased production of substances that influence mood and sleep, like serotonin and melatonin. 

In these cases, melatonin intake can help to regulate circadian rhythm and improve symptoms related to seasonal depression.

5. Decreasing stomach acid

Melatonin can decrease the production of stomach acid and of nitric oxide, which is a substance that triggers the esophageal sphincter to relax (which can reduce reflux). Therefore, melatonin can be used to help for the treatment of this condition, or during more mild.flare-ups. 

6. Helping to treat cancer

Some studies using breast, prostate, endometrial and ovarian cancer cells have shown that melatonin can help improve the effect of cancer treatment or reduce the side effects of chemotherapy or radiotherapy. However, more human studies are still needed to prove this benefit.

How to take it

The production of melatonin gradually reduces overtime due to age or due to constant exposure to stimulating light or visuals. In these cases, melatonin can be consumed as a supplement, either just melatonin or combined with DHEA. It should be taken as directed by a doctor so that your sleep and other bodily functions will be positively affected.

The recommended dose of melatonin can range from 0.3 mg to 0.5 mg, which is about the quantity produced by the body. Melatonin supplements are sold, however, in doses of 1 mg, 1 mg, 2 mg, 3 mg, 5 mg or 10 mg. Therefore, you should start with the lower dose (1 mg) and take it 30 minutes before sleeping. Dosing can be increased by 10 mg per day, depending on your doctor's advice and treatment goals. However, doses over 1 mg can increase the risk for side effects.

This supplement can be prescribed for the treatment of migraines, and more frequently, insomnia, The use of melatonin during the day is usually not recommended, as it can disrupt the circadian rhythm. It can make you feel very drowsy during the day, but awake at night, for example.

Melatonin can also be found in many dietary supplements. These should only be used by people over the age of 19, and should only be taken in a maximum concentration of 0.21 mg. Dietary supplements containing melatonin are not recommended for women who are pregnant or breastfeeding, or for people who perform jobs or activity that require utmost concentration (e.g. heavy machine operation).

A good alternative for increasing melatonin concentration naturally in the body is to consume food that contributes to its production like whole wheat rice, bananas, walnuts, oranges and spinach. 

How melatonin works

The function of melatonin is to regulate the circadian cycle, i.e. the sleep/wake cycle. It also plays a role in the neuroendocrine and body temperature cycles, as these are cyclical and repeat every 24 hours.

In addition, melatonin may also be involved in early fetal development. It can exert direct effects on the placenta by playing a role in establishing diurnal rhythms and synchronizing the fetal biological clock.

Changes to the circadian cycle are associated with sleep disorders and health problems, as this hormone is important for intellectual function, development, mood and good behavior.

Possible side effects

Melatonin is a fairly safe supplement and it is well-tolerated when taken in small amounts for short periods of time and the appearance of side effects is rare. However, even though they are rare, the most common side effects that can arise are fatigue, excessive sleepiness during the day, headache, migraine, difficulty concentrating, irritability, anxiety or worsening of depression.

The intensity of side effects depends on the amount of melatonin ingested. The higher the dose, the greater the risk of some of these side effects appearing.

In children, melatonin supplements can also cause seizures, which is why they should only be taken as prescribed by a pediatrician.

Who should not use melatonin

Melatonin should not be used by women who are pregnant or breastfeeding, or by anyone with an allergy to melatonin or any of the supplement’s components.

You should also avoid taking doses over 1 mg, unless prescribed by the doctor, as you may be at risk for developing side effects.

Melatonin can cause day drowsiness, therefore you should be careful or avoid activities like driving, operating heavy machinery or participating in dangerous activities.