June 23, 2000 -- The results of a new study could put millions of people to sleep -- in a good way. Canadian researchers have found an important connection between levels of the hormone melatonin in the brain and the inability to get a good night's sleep. Their findings may be the key to restful nights for the one in 10 people who suffer from insomnia.
The human body naturally secretes melatonin at nighttime. But as people age, natural melatonin levels decrease, sometimes causing interrupted sleep. When this happens, dietary supplements of melatonin -- purchased at pharmacies or health food stores -- can restore normal sleep patterns, the researchers found. Their first-of-its kind study was presented recently at the annual meeting of The Endocrine Society in Toronto.
"Most older people have [below-normal] melatonin levels at nighttime in their blood, and many of these people have insomnia -- which means they awaken and have trouble falling back asleep," researcher Richard J. Wurtman, PhD, tells WebMD. "For these people, low doses of melatonin are highly effective in restoring normal sleep efficiency." Wurtman is a professor in the brain and cognitive science department at Massachusetts Institute of Technology in Cambridge.
Wurtman and colleagues looked at 30 people age 50 and over, half of whom had insomnia. They found that all 30 participants experienced low blood melatonin levels at night, which shows that melatonin deficiency does not always cause insomnia. The study participants were given either a placebo or one of three doses of melatonin, ranging from 0.1 to 3.0 mg. "All three doses of melatonin improved sleep in the insomniacs, but only the middle dose of 0.3 mg restored sleep to normal," Wurtman says.
That's the ideal dose, he says. But the researchers found that insomniacs often take doses that are 10 times higher than their body requires, making the melatonin less effective.
"This demonstrates the need for doctors to work with their patients to find the correct dose of melatonin that raises the blood melatonin level to its normal range, but does not raise the level above [that] range," Wurtman says.
Lorraine A. Fitzpatrick, MD, a Mayo Clinic physician, tells WebMD that the news is exciting, but cautions patients about proper doses. "Unfortunately, if you went to the health food store, you might get 10 to 100 times the amount used in this study," she says. "Frequently, we see people taking melatonin and getting side effects or hangovers. They may think they're taking the right dose, but they wake up groggy and not able to function. I encourage all of my patients to talk to their doctors about all of the medications they're taking. Interactions can occur with prescription medications that change the affects of drugs."
Wurtman also offers warnings. "Although melatonin was labeled a dietary supplement by the 1994 Dietary Supplement Act in America, it's really a drug," he says. "It's important to let your physician know you're taking it." While melatonin purchased from the pharmacy or health food store is very safe, Wurtman says, higher doses can cause nightmares and possibly can interact with prescription medications.
Wurtman notes that most older people with insomnia don't have trouble falling asleep, because they're exhausted from not sleeping the night before.
"Their trouble is staying asleep," He says. For these people, low doses of melatonin may be the answer. Wurtman suggests looking for pills that contain the recommended dose of 0.3 mg. Many health food stores, he says, carry pills with much larger doses, so the tablets may require splitting.
- The body naturally secretes melatonin at night, but as people age, melatonin levels decrease and may cause interrupted sleep.
- Taking low doses of melatonin -- only 0.3 mg -- can help insomniacs sleep through the night, according to a new study, but doses that are too high will not work as well.
- Experts advise that people should consult with their physicians before taking the supplement.