Melatonin overdose: effects and recommendations

Although melatonin is produced naturally in the body, there are synthetic compounds that contain this substance. Why should overdose be avoided?

Last update: 07 September, 2022

Melatonin overdose can lead to side effects on health. Naturally, this hormone is produced in the pineal gland and is involved in the circadian sleep-wake rhythm. Namely, its secretion affects sleep patterns.

For this reason, it is also available as a medicine, as it is an adjuvant for sleeping difficulties. And although it is considered a drug with relative safety, there are adverse effects that must be considered before taking it.

How is melatonin produced?

The hormone is synthesized from a precursor molecule, serotonin. This is modified by the action of enzymes. In general terms, its secretion is regulated by neurons located in the hypothalamuswhich indicate when and in what quantity it is produced.

In turn, these neurons are stimulated by cells found in the retina that are activated in the absence of light. Therefore, maximum secretion occurs in complete darkness.

The synthetic form of melatonin is used to treat sleep disorders.

For what do you use it?

Although in theory the usefulness of the substance is broad, the studies that justify its use are usually small in scope. This has led to melatonin does not have sufficient consensus approval for the management of various sleep disorders.

In addition, no agreement has been reached on the age at which it can be used. Even so, it is usually prescribed in certain conditions, such as the following:

  • Conciliation insomnia.
  • Sleep phase changes.
  • Irregular sleep-wake rhythm.
  • Sleep resynchronization in shift work.
  • Jet lag.
  • Some dementias, such as Alzheimer’s disease.
  • Circadian rhythm synchronizations in blind patients.

In addition to the scant documentation on its use, Errors in melatonin prescription are also described. In the first place, due to the lack of training of primary care staff on sleep disturbances.

On the other hand, because the substance can be found in two different forms of presentation; fast acting and prolonged release. Each one has specific indications, which can be ignored.

Melatonin overdose and its effects

Melatonin overdose is one of the most common mistakes made when using this substance. In the search for better effects, some tend to overuse it.

In the same way, being classified as a nutritional supplement, it is often used on the recommendation of people who are not fit to do so. Being a molecule with effects on the central nervous system, its indication must be under professional monitoring.

Among other things, There is little documentation of melatonin overdose. In general, it is considered a fairly safe molecule, since few adverse effects are described, which are not usually serious.

Likewise, a maximum recommended daily dose has not been established, but in usual practice between 1 and 10 mg per day are prescribed, always taking into account the age of the patient and the alteration to be treated.

Side effects

Although there is little literature on the subject, some adverse effects due to melatonin overdose have been described. Usually, these are transitory symptoms that are not serious and that improve when the medication is discontinued.

In any case, the documentation of some clinical entities considered more severe tend to worry patients and relatives, so it is important to clarify the frequency of said symptoms.

Does melatonin have an increased risk of producing seizures?

There is a fear that melatonin may cause seizures, especially in children. This fear originates from a study in which six pediatric patients —with significant neurological compromise— received treatment with melatonin and four of them reported seizures.

The main drawback with this result is that the underlying brain lesions could have been the cause of the seizure and not the medication. In addition, the population studied was small, so it does not represent a significant sample. More research is needed on this.

Other authors make it difficult to reach a conclusion on this theory, since there are reports with contrary results. In these improvements in epileptogenic activity are described in patients using melatonin. Therefore, discretion over its use should always be in the hands of a specialist.

Increased sleepiness

In contrast, high doses have caused greater drowsiness in patients, but these amounts are not usually used in the general population. On the contrary, the usual doses generate a synchronization of the sleep-wake cycle, which improves sleep patterns and the level of alertness during the day.

To obtain these results, it is necessary to establish an accurate diagnosis that enables an effective treatment.

Other adverse reactions that may appear with melatonin

In addition, other side effects are described with the use of the “hormone of darkness”, which are usually infrequent and that reverse over time without major importance. These symptoms are considered trivial, since they do not represent a threat to the patient.

Even so, if they cause enough discomfort, the suspension of the drug improves such effects. These adverse reactions include the following:

  • headache
  • Disorientation.
  • Abdominal pain.
  • Acne.
Melatonin overdose can trigger headaches, digestive discomfort, dizziness and disorientation.


Regulation of sleep patterns is the main reason melatonin is used. There are several situations that interfere with night rest and on which you can work to avoid excessive medication.

However, evaluation by trained personnel is —ultimately— the most important action in deciding whether melatonin treatment is the most appropriate. Often, specific improvements in sleep hygiene make it possible to regulate the quality of rest, since disorders are secondary to bad habits.

Among these recommendations, the following are worth highlighting:

  • Be willing to go to bed at the same time each day.
  • Sleep in complete darkness.
  • Avoid sources of distraction such as electronic devices in the room.

On the other hand, the ideal time to take melatonin depends on the purpose for which it is used. In this sense, It is suggested to follow the instructions of a physician with experience in the handling of this supplement.

In fact, there are conditions in which the indication is daytime, while in other cases the intake is done at night. As for the dose, they can be up to 300 mg without observing serious adverse effects. Despite this, low doses are usually handled.

Precautions with the use of melatonin

To conclude, it is important that the consumption of melatonin is under medical supervision. Ideally, the indication should come from a specialist in the area, due to its low use in primary care.

Special care should be taken in patients with underlying diseasessuch as those with autoimmune disorders, hematological disorders, asthma, diabetes and epilepsy.

You might be interested…