Melatonin Dosage & Time Of Day

Melatonin is a chemical found in the brain that is released by the pineal gland. The levels in the blood circulation vary throughout the daily and nightly cycle, leading to changes in arousal known as the circadian rhythm. In the United States it is available in over-the-counter supplements. It is commonly used to treat circadian rhythm disorders, which often lead to insomnia. Before taking melatonin and for the diagnosis and treatment of insomnia and other conditions, it is important to consult a physician or other qualified healthcare professional.

Circadian Rhythm

A circadian rhythm is a roughly 24-hour cycle of physiological, behavioral or biochemical processes. They are endogenous, or "built in," but influenced by the environment, especially the light-dark cycle. Sleep is one such rhythm, and is influenced by the level of melatonin released by the pineal gland.

Melatonin

Levels of melatonin are low in the daylight and rise after the onset of darkness. They peak in the middle of the night and fall to low levels just before dawn. It is not stimulated exclusively by light; however, light influences its concentration. The body's own internal clock regulates the level of melatonin.

Supplemental Use

The authors in a 2011 literature review in the medical reference journal UpToDate titled "Physiology and Clinical Use of Melatonin" recommend taking 0.3 mg of melatonin before bedtime, or 0.2 mg if the person weighs less than 120 pounds. If he does not respond in a week, the dose is doubled. If the person responds at first and then fails to respond, time off from melatonin can re-establish its efficacy. While it has been tested in a number of conditions, it appears to be most effective for insomnia and jet lag.

Side Effects

Melatonin is relatively non-toxic. It is not recommended for general use by people with seizures or those on anticoagulant drugs, or blood thinners, such as warfarin, without the advice of a physician. It is presently not recommended for children until further studies are completed. It is not recommended for pregnant women, and should be used cautiously by diabetics and those with high blood pressure and glaucoma. No major side effects are likely in healthy people, but large doses may cause daytime drowsiness.