You are getting sleepy.... (Supplement Watch).

Having trouble falling or staying asleep? You're not alone. One in three people say they have problems sleeping almost every night. And if you're a poor sleeper, feeling tired and crabby could be the least of your problems.

"By any measuring stick, the deaths, illness, and damage due to sleep deprivation and sleep disorders represent a substantial problem for American society," says the National Commission on Sleep Disorders Research.

Three new studies suggest that poor sleep may be helping fuel the national diabetes epidemic:

* When researchers limited healthy young people to only four hours of sleep a night for six nights, it impaired their ability to keep blood sugar levels on an even keel. (1)

* In a not-yet-published study, volunteers who averaged no more than 6 1/2 hours of sleep a night were more insulin-resistant than volunteers who slept at least 7 1/2 hours. They needed to produce 30 percent more insulin to keep their blood sugar levels normal.

* When healthy people were kept awake all night, they were more insulin-resistant the next day. (2) Insulin resistance raises the risk of diabetes and heart disease.

Snoring may also push us down that path. In two new long-term studies of more than 72,000 men and women, snorers were twice as likely to develop diabetes as non-snorers. (3,4) What's the connection? Snoring interferes with normal breathing, which leads to less oxygen in the blood. And that may trigger the body's stress response, which raises blood sugar levels.

Wouldn't it be wonderful to have a cheap, safe, and readily available alternative to prescription sleeping pills? According to supplement manufacturers, valerian and melatonin can help you sleep like a baby. The research tells a different story.

VALERIAN

The dried roots of the valerian plant have been used since the 1500s to soothe nerves and help people sleep. Yet the evidence on valerian and sleep is "inconclusive," according to Clare Stevinson and Edzard Ernst of the University of Exeter in England. The two alternative-medicine experts have reviewed the nine best studies of valerian conducted through 1999. (5)

Most were very small (they had a dozen or fewer participants). Unlike good sleep studies, they didn't monitor how close to bedtime the volunteers exercised, ate, consumed alcohol or caffeine, or did other things that could have affected their sleep. And three of the studies used a placebo that tastes very different from valerian, so the volunteers might have been able to tell which they were getting.

Some of the studies gave volunteers valerian for a single night; others gave it every night for up to four weeks. The bottom line: None of the studies found any improvement in both objective measures of a good night's sleep (brain wave patterns during the night) and subjective measures (questionnaires or alertness tests the day after). The best sleep studies track both measures.

Since then, a tenth study--the best-designed yet--found that valerian is of little or no use in treating insomnia. Sixteen insomniacs who were given 600 mg of the Sedonium brand of valerian for two weeks didn't fall asleep faster--or sleep any longer--than when they were given a lookalike (but valerian-free) placebo. (6)

"Although this study was small, its rigorous design compared with previous trials gives it added weight," says Michael Rotblatt of the UCLA School of Medicine and co-author of Evidence-Based Herbal Medicine (2002, Hanley & Belfus, Inc.).

"Still, even though valerian's effectiveness hasn't been demonstrated beyond a reasonable doubt," he adds, "it's reasonable for someone with sleep problems to try it as a non-addictive alternative to drugs." That's because valerian doesn't cause a hangover or impair alertness or concentration the next morning, the way Valium, Halcion, Xanax, and other prescription drugs sometimes do. And in the ten best studies, valerian didn't seem to cause any other serious side effects (although the herb hasn't been tested in long-term studies or on pregnant or nursing women).

If you try valerian, just be aware that you may not get what you paid for. In the fall of 2000, the private research firm Consumerlab.com tested a single sample of 17 popular brands to see if they contained sufficient levels of valerenic acids, which some researchers believe are the active ingredients in valerian. All four of the brands that contained valerian root powder plus extract passed. So did four of the seven made just from extract. But five of the six that were made just from powder failed.

The Bottom Line: There is not enough evidence to conclude that valerian can help you sleep better. And researchers have never tested its long-term safety.

MELATONIN

"Taking melatonin is not going to help with the garden variety of sleep problems most people face," says Andrew Monjan, Chief of Neurobiology of Aging at the National Institute on Aging in Bethesda, Maryland. "Studies have shown it to be effective in improving sleep quality usually only for people whose waking and sleeping is out of sync with the daily cycle of light and dark, such as with shift work, jet lag, or blindness."

Melatonin is a hormone produced within the brain that helps keep us awake during the day and asleep at night. The release of small amounts by the pineal gland in the evening starts most people towards their date with the sandman.

Melatonin manufacturers are fond of claiming that our brains produce less melatonin as we get older. That's not true--though heart disease and some other conditions, as well as beta-blockers, ibuprofen (Advil), and some other drugs can cause production to drop. And it's not the only melatonin myth.

"There's no relationship between the amount of melatonin you make at night and whether or not you have bad sleep, or whether more melatonin will help you sleep better," says pioneering melatonin researcher Alfred Lewy, director of the Sleep and Mood Disorders Laboratory at the Oregon Health & Science University in Portland.

And in a recent study by Richard Wurtman and colleagues at MIT, four weeks of melatonin every night 30 minutes before bedtime didn't help 30 seniors fall asleep faster, sleep longer, or awaken less during the night. (7) It didn't matter whether they took 0.1 mg, 0.3 mg, or 3 mg, or whether or not they suffered from insomnia.

The only benefit: Among the insomniacs, those who took melatonin were asleep 85 percent of the time they were in bed. On the placebo, they were asleep 78 percent of the time. "That's important," says Wurtman, "because older people complain about not being able to stay asleep at night."

If you decide to take melatonin, you could end up doing yourself more harm than good.

"The problem, other than that it might not work," cautions Monjan, "is that if you take it at an inappropriate time during your circadian (daily) rhythm, you may reset your body clock to the wrong time and make things worse for yourself."

As for the risk of taking melatonin for long periods of time: "we don't know what they are, though no problems have come to light in people thus far," says Monjan.

The Bottom Line: If you have jet lag or your body clock is out of sync, melatonin may help you reset it. But if you can't sleep for any other reason, melatonin probably won't help. Researchers have never tested its long-term safety.

(1) Lancet 354: 1435, 1999.

(2) Diabetes Nutr. Metab. 13: 80, 2000.

(3) J. Intern. Med. 24: 13, 2000.

(4) Amer. J. Epidemiol. 155: 387, 2002.

(5) Sleep Medicine 1: 91, 2000.

(6) Pharmacopsychiatry 33: 47, 2000.

(7) J. Clin. Endocrinol. Metab. 86: 4727, 2001.

RELATED ARTICLE: Asleep at the switch.

You may have seen ads for these three popular sleep supplements. Don't fall for the hype.

* Alluna. Valerian plus hops is sold in Europe to help people sleep. GlaxoSmithKline, which sells the Alluna brand in the U.S., claims that clinical studies with more than 3,500 people show that it "helps people fall asleep faster and sleep more soundly." Yet the giant drug company could only come up with one study--in 18 people--that compared Alluna with a placebo. And it only showed that the supplement could be safely taken by those who use heavy machinery or drive.

* Natrol Stress Complex. Natrol claims that the six B-vitamins in its Stress Complex (which also contains valerian and melatonin) "play a crucial role" in getting proper sleep. But the three studies the company sent us had nothing to do with sleep (or stress). They didn't even use the same combination or levels of vitamins found in Stress Complex. And the consultant Natrol referred us to said that she has advised the company to drop its claim about B-vitamins and sleep.

* Kava Chews. Chew on this kava-containing candy a few hours before bedtime and you'll fall asleep faster, says the manufacturer. While kava may help people who suffer from clinical anxiety relax, there are no good studies showing that the herb helps people fall or stay asleep. And the latest news may keep kava-users awake. More than two dozen cases of liver toxicity in Europe and the U.S. have been linked to the herb.

RELATED ARTICLE: Before you pop that pill.

Before you turn to sleep supplements or prescription drugs, try these sleep-boosters (and avoid the sleep-busters).

SLEEP-BOOSTERS

* People who exercise regularly fall asleep faster, sleep for a longer time, spend less time awake during the night, and get more of the deeper slow-wave sleep than people who don't exercise.

* A warm bath can help you fall asleep because it raises body temperature; the subsequent cooling triggers sleep.

* Covering your eyes with a mask or towel may help you sleep better. If melatonin levels are exquisitely sensitive to light, as recent research suggests, the darkness may promote sleep by keeping your body's natural melatonin levels up.

SLEEP-BUSTERS

* Alcohol can help you fall asleep, but it can also increase the time you're awake during the second half of the night, especially if you're older.

* People who take the painkillers aspirin or ibuprofen (Advil) within an hour of bedtime awaken more often and spend more time awake during the night than people who take acetaminophen (Tylenol).

* While regular exercise can help you sleep better, exercising within an hour or two of bedtime can keep you awake.

If all else fails, your sleep troubles may be caused by a medical condition and you should consult a physician, says Andrew Monjan of the National Institute on Aging. Many sleep-related problems--such as snoring, sleep apnea, and restless leg syndrome--can be corrected. It's also possible that, for some reason, your sleep-wake cycle is out of whack. That's the case with 15 to 20 percent of people who suffer from insomnia, says Monjan. If so, taking melatonin may help reset your body clock.

RELATED ARTICLE: Leaving on a jet plane.

"Melatonin is the chemical signal that helps our internal body clock know when it's dark out and time to sleep, or when it's light out and time to be awake," says Alfred Lewy of the Oregon Health & Science University in Portland.

And that can help you deal with jet lag. In nine of the ten best studies, taking between 0.5 mg and 5.0 mg of melatonin between 10 p.m. and midnight at the destination was "remarkably effective in preventing or reducing jet lag from flights crossing five or more time zones," says Andrew Herxheimer of the UK Cochrane Centre in Oxford, England, which reviews and summarizes the evidence for medical therapies. (1)

Melatonin seems to help more when you fly from west to east and when you cross more time zones. Timing is also important. If you take melatonin too early in the day, you may become sleepy before bedtime and it may take you longer to adapt to your new time zone.

"The best instructions are complicated," says Lewy. Here's a simplified version of his recommendation for reducing jet lag on a New York to London round trip:

* The day before you leave, take 0.5 mg or less of melatonin in the afternoon (it could make you drowsy). For a few days after you arrive in London, get some morning sun and take 1 to 3 mg of melatonin before bedtime.

* The day before your return flight, take 0.5 mg or less of melatonin as soon as you get up in the morning. After you arrive in New York, get some late afternoon sun and take 1 to 3 mg of melatonin before bedtime the first night. Continue the sunlight exposure for a few days.

"You will never be able to avoid jet lag entirely," says Lewy. "But with the right combination of melatonin and light, you can cut down the number of days you have it."

(1) Cochrane Database Syst. Rev. (1): CD001520, 2001.