Melatonin: Chemical | Organic composition
Last modified: Sunday, 31. May 2009 - 5:09 pm
Melatonin is made from tryptophan, a type of amino acid. Pinealocytes absorb tryptophan from the blood. Through a series of chemical reactions, the pinealocytes then convert the amino acid into melatonin.
Melatonin is a relatively simple type of chemical compound. It is rapidly absorbed and will reach its peak concentration within about an hour after it is swallowed. Melatonin is fat soluable, which means it is able to enter all the cells of the body, including brain cells. So melatonin can easily leave the bloodstream and enter brain cells. But melatonin does not remain in the bloodstream for very long as it is quickly broken down by the liver. It takes about 30 to 40 minutes for the liver to remove one half of the melatonin that is present in the blood.
Many over-the-counter drugs contain melatonin. Some of these products are made from animal sources. However, most commercially available melatonin is synthetic.
Since melatonin is naturally found in some foods, it is legal to sell it as a dietary supplement in the United States under the U.S. Dietary Supplement Health and Education Act (DSHEA) of 1994. Dietary supplements like multivitamins are not as carefully regulated by the federal government as are prescription medications. However, the amount of melatonin in food is very low. A person would have to eat 120 bananas or 30 large bowls of rice to get the same amount of melatonin that is contained in a 3-mg capsule. The amount of melatonin contained in dietary supplements is much, much higher than that produced by the pineal gland or obtained through food.
Since commercially available drugs containing melatonin are not regulated, they are not held to the same high standards of purity and efficacy as are other medications. Melatonin, being a hormone, is just as potentially dangerous as other naturally occurring substances such as estrogens and androgens.
Drugs that are not regulated by the FDA are more likely to be contaminated with impurities. They may also be inaccurately labeled and not contain the amount of melatonin listed on the label. According to the National Sleep Foundation, a batch of melatonin was examined and found to contain much more of the hormone than was listed on the label. According to another study, one third of the medications that supposedly contained melatonin did not contain any melatonin, while an additional 40% contained much less than was stated on the label.
While many commercially available preparations contain only melatonin, many others contain a combination of this hormone with other active ingredients. Some of these other ingredients may be vitamins such as pyridoxine, while others are natural remedies such as kava root and valerian. It is even available combined with acetaminophen, a common over-the-counter pain reliever. Frequently, the long-term effects and safety of these other ingredients are not known. Even less is known about any possible interactions between these substances and melatonin, because melatonin has been available and used commercially for only a short period of time. Many experts have suggested that it would be preferable to test melatonin in controlled studies to determine if it is effective and safe before it was released on the market and used by millions of people.
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