The importance of a good night’s rest cannot be overstated. Poor sleep is linked to all-cause mortality, which means getting too little or too much sleep are “significant predictors of death,” according to a 2010 meta-analysis study. But good sleep is increasingly a privilege, as stress, workloads and the trappings of a modern lifestyle squeeze out valuable shut-eye.

Naturally, there are medications that aim to fix this problem. Home remedies like extracts of valerian root, a pinkish-white flower, have existed in North America since the mid-19th century. Contemporary drugs like Ambien, an insomnia drug, or melatonin, a sleep-related hormone the body naturally produces, make up an industry generating $70 billion per year. But whether they actually help is a different question.

The New Sandman

All sleep aids work in essentially the same way, by boosting production of a neurotransmitter known as GABA. GABA helps to quiet down the activity of neurons in our brains, and it’s an important part of our sleep cycles. Almost every drug that makes you drowsy, from barbiturates to benzos to valerian root to alcohol, utilizes this chemical. Low levels of GABA have also been linked to insomnia and anxiety. But sleeping pills might not be the best path to a healthier relationship with sleep. As neuroscientist and “sleep diplomat” Matthew Walker explains in his 2017 bestseller Why We Sleep: “Sleeping pills do not provide natural sleep, can damage health, and increase the risk of life-threatening diseases.”

While taking drugs like Ambien may help you become unconscious, sedation is not the same as sleep. These hypnotic drugs can actually restrict the deeper brain waves produced during REM sleep, leading to grogginess and forgetfulness the following morning. Feeling sluggish the next day might lead people to consume more caffeine, making sleep difficult and perpetuating the cycle.

Sleep, Naturally

Other people opt for a different route with melatonin, a hormone that tells our brains it’s time to sleep. Melatonin is produced by the body, and it’s part of our circadian rhythms, internal cycles of alertness and drowsiness that operate on a roughly 24-hour timetable.

Melatonin signals our brains that it’s dark out, and to prepare for sleep. It has become popular among those looking for a good night’s rest. The hormone may not actually induce better sleep, though, and the effects are modest at best. Some commercially-available supplements have issues with quality control as well.

But keeping our circadian rhythms regular can have important health implications. Liz Cash, an assistant professor at the University of Louisville, studies circadian rhythms in people with cancer. She says patients with disrupted rhythms have worse overall survival rates than patients who maintain more regular cycles.

“When individuals experience disruptions in these rhythms over the long-term (many years), this can lead to changes in physical health and contribute to the development of disorders like obesity, diabetes and cancer,” Cash says.

Circadian rhythms are so important that the disruptions caused by working a late-night shift makes certain jobs likely carcinogens, according to the World Health Organization.

Sleeper, Beware

Though losing sleep is undoubtedly dangerous, some prescription sleep aids also come with rare but serious side effects. In late April, the Food and Drug Administration put a black box warning — the agency’s most severe label — on three of the most popular insomnia drugs: eszopiclone (Lunesta), zaleplon (Sonata), and zolpidem (Ambien.) The FDA logged 66 incidents of semi-conscious behavior after taking the drugs, such as sleepwalking or driving asleep, that resulted in serious injury or death.

But these so-called Z drugs don’t work much better than a placebo, according to a 2012 meta-analysis of about 4,400 patients across 13 studies. To make matters worse, when you stop taking some sleeping pills, they can cause “rebound insomnia” which makes it even more difficult to fall asleep.

As Walker explains in his book, the brain responds to drugs by trying to become less sensitive and alters its balance of receptors, creating a type of dependency. “This is also known as drug tolerance,” he writes.

For this reason, Cash says discontinuing sleeping meds requires slowly tapering down the dose, rather than stopping immediately, and should be supervised by a doctor. “Generally it is recommended that sleep medications be adopted only for the short-term, for four consecutive weeks of use or less,” she says.

Not getting the right amount of sleep can be detrimental to one’s health. But while drugs for sleep may help in a pinch, their side effects may not be worth it. Overall, there really are no long-term substitutes for the real thing: deep, restful slumber.