Melatonin Overdose – Symptoms, Causes, Amount, Treatment


Melatonin is a chemical that is found in humans, plants, animals and even microbes. Among humans and animals, melatonin is the chemical responsible for facilitating the circadian rhythm. The circadian rhythm refers to the biological process where the body undergoes a self-sustained and adjusted cycle which runs for 24 hours. Sleeping and feeding patterns are the most common examples of circadian rhythms in the human body. In sleeping, the first 12 hours of the day is the time when the body is awake, here, the level of melatonin in the body is at its lowest. But as dark approaches, the melatonin in the body increases triggering the feeling of sleepiness. The change in light and dark pattern commences in a period of 24 hours, and sustaining or adjusting to these changes is our circadian rhythm.

Nowadays, we can see a number of products containing the chemical or the neurohormone melatonin, some of them can be purchased over the counter or without prescription. Pharmaceutical products with melatonin have been used to treat or manage a wide range of conditions, but primarily, this neurohormone is used to correct disorders affecting the circadian rhythm. Melatonin is also seen to be a potential treatment to other conditions such as GERD, immune disorders, cancer, seasonal affective disorder or SAD, depression, sexual dysfunction and even Alzheimer’s disease.

Symptoms and Signs of Melatonin Overdose

Case studies on people taking large doses of melatonin revealed certain unwanted effects. The adverse effects include:

  • Hypothermia
  • Grogginess felt the day after the medication was taken
  • Reduced blood flow
  • Irritability

There are also documented cases of adverse effects experienced when the patient takes the melatonin for a long period of time (more than 3 months or more than the prescribed time for treatment). The adverse effects include:


  • Drowsiness
  • Unknown effects to people with auto-immune disorders
  • Orthostatic hypotension
  • Decrease in blood pressure
  • Decrease flow of blood to the brain

Medical overdose from melatonin is considered non-life threatening, case studies reveal only one overdose victim of melatonin, and the primary symptom exhibited by the patient is confusion. Like any other drug or medicine, it is not advisable for people to be taking large doses. Going beyond the prescribed duration of treatment is also not advisable.

Safe Amount of Melatonin

Melatonin is primarily used to treat sleep disorders, it is very important for patients with sleeping problems to consult with a physician in order to determine the appropriate dose and appropriate length of treatment for the case. Melatonin itself does not induce sleep, but it makes the body susceptible to the environmental changes that promote sleep. For example, people with jet lags or those working on rotating night shifts are most likely to have disruptions in the circadian rhythm, small doses of melatonin are given hours before bedtime to correct their circadian rhythm and make them more responsive to the light-dark cycle that normally induces sleep. A dose of 3 mg of Melatonin is usually given hours before bedtime, the length of treatment is determined by the physician but it can last from several weeks up to three months.

Causes of Melatonin Overdose

Overdose from melatonin may be due to a myriad of reasons, psychological reasons and addictive behavior are the primary ones.

Treatment for Melatonin Overdose

Treatment begins with the discontinuation of the medication, if the patient exhibits drowsiness and confusion, the patient is more likely to be observed carefully and would be advised to rest and discontinue any physical activity. Patients will be observed mainly for seizures. Other symptoms of overdose would be treated conventionally depending on the case and the physician’s discretion.

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