Melatonin, antioxidant and useful for sleeping well: what it is, effects, use

Melatonin is a hormone produced in our body and best known for the treatment of insomnia and for the absence of serious side effects.

Melatonin is a hormone produced by our body and was first discovered in 1958, when Aaron Lerner isolated it from a pineal gland of bovine origin.

This substance, which is mainly produced by our pineal gland starting from the amino acid tryptophan, is present in various parts of the body and its concentration in our intestine is tangibly higher than the blood concentration.

The benefits of melatonin depend in part on the interaction between this hormone and its receptors and are in part independent of the receptor itself. Thanks to these numerous functions, melatonin finds numerous applications in medicine.

What is melatonin

As anticipated, melatonin is a hormone produced mainly by our pineal gland starting from the amino acid tryptophan: first of all this amino acid is transformed into serotonin and subsequently this hormone is converted into melatonin , through enzymatic reactions in which mainly two enzymes present in the pineal gland participate.

Proper production of melatonin depends on the presence of normal light and dark conditions. In particular, in fact, the light signals our body to stop the formation of this substance; vice versa the dark stimulates its secretion. Generally, the release of this molecule in humans begins immediately after sunset and peaks during the night. In fact, the correlation between melatonin and insomnia is well known, a condition that many people suffer from.

Melatonin is not found only inside the pineal gland, but we find it in numerous parts of the body: the retina, bone marrow, skin, platelets, white blood cells and above all the gastrointestinal tract. In fact, it is estimated that the concentration of melatonin at the gastrointestinal level is 400 times higher than that in the pineal gland itself.

As we have anticipated, the effects of melatonin are many: in the next paragraph we will deepen them in more detail. Among the main functions we can mention the regulation of circadian rhythms and sleep, cancer prevention and protection from oxidative stress.

Melatonin: properties and benefits

Summarizing what has been said so far, we can synthesize that melatonin is a hormone produced by the pineal gland and then poured into the circulation so that it can reach the target organs, where melatonin can perform its function. This function may depend on the interaction of melatonin with its receptor (present in the target organ) or be independent of the receptor. Among the functions dependent on the receptor we find the regulation of circadian rhythms, sleep and the function of anticancer prevention; among the independent ones the antioxidant function. Let’s see them now in detail.

✓ Regulation of circadian rhythms and sleep

Melatonin is effective in regulating circadian rhythms, such as the sleep-wake rhythm or body temperature cycles. Conversely, melatonin deficiency can be associated with disturbances of these rhythms, which negatively affect our state of health. In children, for example, the dysregulation of circadian rhythms is associated with problems of mood, behavior and development, including neurological ones.

In particular, it has been known for a very long time that melatonin is identified as an important physiological regulator of sleep: in fact, the propensity to sleep usually occurs 2 hours after the start of melatonin production.

In some cases, such as aging, in the presence of certain diseases such as diabetic neuropathy or some neoplasms, in the case of Alzheimer’s and during drug therapy with certain drugs such as beta-blockers and non-steroidal anti-inflammatory drugs, the production of this important hormone is reduced to a more or less marked extent, depending on the case.

Supplementation with melatonin improves the situation as it acts as a signal of darkness for various organs, including the central nervous system and therefore can also be used in the absence of light, such as for completely blind individuals, or for those suffering from others. disturbances in the circadian rhythm of sleep-wake, as in the case of jet lag or night shifts. In fact, melatonin effectively anticipates the start of sleep and is used for phase shift following long flights in healthy individuals, although it is not approved for this indication.

✓ Fertility and human reproduction

Melatonin also appears to be involved in the early stages of fetal development and has direct effects on the placenta in the first trimester of pregnancy. Furthermore, in some studies, melatonin appears to have stimulated the production of beta HCG, bringing it to optimal concentrations for pregnancy. In particular, it is also reported that in a study conducted on 61 women undergoing cycles of medically assisted fertilization it was found that the levels of melatonin at the follicular level were directly linked to markers of ovarian reserve and to the outcome of fertilization itself. This result, according to the authors, supports the hypothesis that melatonin has a supportive action on the progression of the ovarian cycle.

Furthermore, melatonin administered daily in the amount of 3 g allowed to reduce intra-follicular oxidative stress, thus further improving fertilization rates.

✓ Cardiovascular health

Melatonin has been shown to be involved in the regulation of blood pressure and, consequently, in cardiovascular health. In particular, several studies have reported that melatonin exerts particularly positive effects on damage due to ischemia, on pulmonary hypertension, on heart valve diseases, on vascular diseases and on the parameters of lipid metabolism.

For example, it has been shown that supplementation with melatonin has allowed to reduce the extent and number of atherosclerotic plaques, as well as to improve the conditions of dyslipidemia in patients with non-alcoholic hepatic statosis: a treatment for 14 months with 10 g of melatonin per day showed a clear reduction in triglyceride and LDL cholesterol (bad cholesterol) values.

✓ Antioxidant function

The antioxidant function of melatonin protects the brain and also the gastrointestinal tract from any ulceration. In fact, melatonin is able to interact with oxygen free radicals (ROS) and nitrogen (NOS), neutralizing them. Compared to other antioxidants such as vitamin C and vitamin E, melatonin is much more effective both in vitro and in vivo. In fact, thanks to its cascade action it has been shown that a molecule of melatonin is able to eliminate about 10 molecules of ROS, compared to other antioxidants that can eliminate one.

The advantage of melatonin as an antioxidant also lies in the fact that all individuals are able to produce it by themselves, unlike the other molecules mentioned, which must be introduced with the diet, and its production is inducible, i.e. it can increase under conditions of increased need.

✓ Immune function

Melatonin has shown benefits regarding the immune response in animals and humans. The same antioxidant actions of melatonin, in fact, allow an immune stimulation and facilitate the decrease of the inflammatory response.

Many studies both in vitro and in vivo have shown that melatonin has an immunomodulatory capacity: it regulates the innate and specific immune response thanks to the regulation of the proliferation of cells of the immune system and the secretion of mediators of the immune system. For this reason it is a molecule with antiviral, antibiotic and antiparasitic action.

✓ Oncological prevention activities

A large number of studies have shown an anticancer effect of melatonin due to its involvement in multiple reactions. This effect is not always associated with its antioxidant action, but sometimes produces this effect by increasing oxidative stress or thanks to an anti-apoptotic or pre-apoptotic effect, thanks to which it stimulates the death of cancer cells in many types of cancer, such as gastric and cervical tumors.

Where is melatonin found in food

In addition to being produced by our body, melatonin is also found in some foods of plant origin such as bananas, grapes, cherries, pineapple, oranges, barley, olive oil and rice. However, melatonin finds its main use through specific supplements. Let’s see now how to use them.

How to use melatonin supplements

When a melatonin supplement is used, times and doses are essential to determine the effectiveness of the treatment. As for the dosage, for example, we will need a smaller quantity in case of insomnia and a more abundant quantity if we want to use it for its antioxidant function. Furthermore, in the latter case, the time of recruitment during the day will not be important; when instead we want to improve the circadian rhythms we will be careful to take melatonin after dinner, a couple of hours before going to bed for the night.

As you may have already noticed in the paragraph on benefits, the dosages used can vary a lot:

  • Insomnia: in case of insomnia and circadian rhythm disturbances due, for example to the jet leg, dosages between 0.3 mg and 3-5 mg are recommended;
  • As an antioxidant: the 3 mg dosage already seems to have an antioxidant effect and has been used to improve fertility rates and improve oxidative stress at the follicular level;
  • Cardiovascular wellbeing: in the case of cardiovascular problems, the dosage can be significantly higher, up to 10 mg per day.

The integration can take place through the products widely present on the market: it is generally found in tablet form, but it is also possible to find it in drops, a more practical format in children’s insomnia.

Is it safe to take melatonin every night? Is it addictive?

Several studies have been performed to confirm the safety of melatonin supplementation. The use of melatonin supplements has been shown to be safe for both animals and humans, for short periods, even in high doses. Chronic use of these substances showed no habit-forming capacity and the side effects were comparable to placebo or very mild such as dizziness, headache, nausea and sleepiness.

There are still no data regarding pregnant or lactating women, who are not recommended to take exogenous melatonin.

Melatonin and children: does it work? Is it safe?

It is possible, and in some cases advisable, to use melatonin in children. In fact, there are several studies in which the integration of this substance has been used to improve sleep in pediatric patients, concluding that melatonin is safe and effective both in primary sleep disorders and in sleep disorders associated with other neurological conditions, such as attention deficit or hyperactivity.

It is important, however, to underline that the levels of melatonin vary according to age: children up to 3 months of life produce very small quantities and only from the 3rd year of life will there be a regularization of the sleep-wake rhythm. It is therefore essential to contact a specialist and rely on his advice regarding the integration of any substance, including melatonin.

Melatonin: contraindications, warnings and risks

Melatonin supplements are mainly used to improve sleep and their intake can therefore be chronic. Although it is known that supplementation with melatonin is not addictive, it is possible that chronic intake can lead to daytime sleepiness (especially when we use “slow-release” melatonin supplements), as well as headache and dizziness. These are therefore the main contraindications of melatonin: in the event of the aforementioned conditions, we advise you to suspend its integration and contact your reference specialist.

There are also less common side effects including: short-lived depression, mild tremor, anxiety, abdominal cramps, irritability, reduced attention, confusion, disorientation and hypotension.

We also suggest that you take care to take melatonin if you are already being treated with other drugs and in any case always ask your doctor for advice. In fact, melatonin can interact with the following drugs: anticoagulants, antiepileptics, antihypertensives, sedatives, contraceptives, immunosuppressants, antidepressants and drugs for diabetes.

Finally, it is important to note that there is controversial evidence in the case of autoimmune diseases: there are some studies that have linked melatonin (both exogenous and endogenous) in the development of some autoimmune diseases such as rheumatoid arthritis and multiple sclerosis. In these cases, although there is no conclusive evidence, the use of melatonin is not recommended.

Where to buy melatonin

As we have seen above, melatonin is generally found on the market in the form of tablets or drops. We can buy it at a pharmacy, herbalist’s shop or in specialized online stores. The dosages, as we have seen, may vary according to the use we want to make of them. Generally, however, melatonin is used to sleep well and we often find it in supplements combined with other active ingredients useful for counteracting insomnia such as valerian, escolzia or passionflower. In any case, for an informed choice, we recommend that you be guided by a professional in the field.


Melatonin is a supplement that is found to be safe and free of serious side effects, even when used for a long time. It is mainly used in cases of insomnia and to regulate sleep-wake rhythms, which can compromise physical or neurological development and our health. However, it can also be a good ally in case of high oxidative stress and in some types of cancer, in association with pharmacological therapies indicated by specialists.

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