Melatonin and Sleep
Wednesday, January 1, 2014
is released into the blood. Usually, this occurs around 9 pm. As a result, melatonin levels in the blood rise sharply and you begin to feel less alert. Sleep becomes more inviting. Melatonin levels in the blood stay elevated for about 12 hours - all through the night - before the light of a new day when they fall back to low daytime levels by about 9 am. Daytime levels of melatonin are barely detectable.
Besides adjusting the timing of the clock, bright light has another effect. It directly inhibits the release of melatonin. That is why melatonin is sometimes called the "Dracula of hormones" - it only comes out in the dark. Even if the pineal gland is switched "on" by the clock, it will not produce melatonin unless the person is in a dimly lit environment. In addition to sunlight, artificial indoor lighting can be bright enough to prevent the release of melatonin.
The amount of melatonin released at night varies among individuals, but it is somewhat related to age. Children on average secrete more melatonin than adults, which decreases further with age. However, research has shown that older people with sleep problems do not always have lower melatonin levels than people who experience normal sleep.
Chances are good that you have seen melatonin in health food stores or in an advertisement or article. No other hormone is available in the United States without a prescription. Because melatonin is contained naturally in some foods, the U.S. Dietary Supplement Health and Education Act of 1994 allows it to be sold as a dietary supplement (e.g., vitamins and minerals). These do not need to be approved by the Food and Drug Administration (FDA) or controlled in the same way as drugs.
Because it is not categorized as a drug, synthetic melatonin is made in factories that are not regulated by the FDA. Listed doses may not be controlled or accurate, meaning the amount of melatonin in a pill you take may not be the amount listed on the package. Most commercial products are offered at dosages that cause melatonin