America just can't seem to get enough of melatonin. The popular "sleep" supplement has an ever-growing fanbase of people (use of the supp quintupled between 1999 and 2018, per NIH research) who use it to fall asleep at night, combat jet lag, and even help calm anxiety before medical procedures. These days, roughly two in 100 people say they take melatonin. But new research suggests that melatonin may do more than just help you conk out when you're too wired.
A study, which was published in the journal Occupational & Environmental Medicine, found that melatonin seems to help actually some people repair DNA damage while sleeping.
As you may know, melatonin is a hormone that your brain creates naturally in response to darkness, per the National Center for Complementary and Integrative Health (NCCIH). Melatonin can help with the timing of your circadian rhythms (a.k.a. your internal clock), and can help you fall asleep.
But the DNA repair element is a totally new health perk. Here’s what the study found, plus what could be behind this, according to doctors.
Meet the expert:W. Christopher Winter, MD, is a neurologist and sleep medicine physician with Charlottesville Neurology and Sleep Medicine and host of the Sleep Unplugged podcast; Jamie Alan, PhD, is an associate professor of pharmacology and toxicology at Michigan State University; Parveen Bhatti, PhD, is a study co-author and cancer control researcher at BC Cancer Research Institute
What did the study find?
For the study, researchers recruited 40 night shift workers and divided them into two groups. One group took a melatonin supplement after work before going to sleep for four weeks. The other group took a placebo pill.
During that time, the researchers took urine samples and measured for something called creatinine-adjusted 8-hydroxy-2′-deoxyguanosine (8-OH-dG) to look for the body’s capacity to perform oxidative DNA damage repair. In case you’re not familiar with it, oxidative DNA damage is a change in DNA that can happen due to things like exposure to inflammation, toxins, and poor diet, raising the risk of serious health complications, including cancer. Higher concentrations of this molecule in urine suggest that the body is able to overcome oxidative DNA damage more easily, according to the researchers.
The participants wore activity trackers to better detect how long they slept. The researchers also measured 8-OH-dG levels in the participants' urine after sleeping periods and during the night shifts.
Here's what they found: 8-OH-dG levels were 80 percent higher during the sleeping periods in the melatonin group compared to those who took a placebo, suggesting they experienced better DNA repair during that time.
What does this mean? Well, since working at night disrupts the body’s circadian rhythms, it has been linked with a slew of serious health issues, including diabetes, heart disease, and obesity. But the findings suggest that taking melatonin may help counteract the harms that can come with staying up all night and sleeping during the day.
How much melatonin did the participants take to see results?
The participants took three milligrams of melatonin before bed over the four-week study period. The researchers wrote in the study that they chose this dose because it was likely enough to influence most participants' sleep-wake cycles.
How does melatonin help repair DNA?
It’s important to point out that the study just found a link between taking melatonin and the production of 8-OH-dG. It didn’t actually prove that people who took melatonin had better DNA repair.
Jamie Alan, PhD, an associate professor of pharmacology and toxicology at Michigan State University, also points out that you can have "silent" mutations in your DNA that don't actually have an impact on your health. Plus, Alan says the study was small and specific, and that more research is needed on this topic before we can start extolling the supp's DNA-repairing success.
Still, the findings are definitely interesting.
When you work a night shift, your body suppresses production of melatonin to help you stay awake, the researchers explain. But that makes it harder for your body to repair oxidative DNA damage that naturally occurs in cells. If this is left unchecked, it can raise the risk of developing certain illnesses and diseases.
It's possible that by taking melatonin to sleep, the participants counteracted this, boosting DNA repair in the process, says W. Christopher Winter, MD, a neurologist and sleep medicine physician with Charlottesville Neurology and Sleep Medicine and host of the Sleep Unplugged podcast.
“Our body is constantly monitoring for and attempting to repair cellular damage, even at a DNA level,” he says. “This is often spoken about in terms of oxidative damage, and certain chemicals facilitate this process. This study is showing evidence that melatonin may aid in this process.”
Will taking melatonin help my body repair DNA?
It’s hard to say at this point. The study focused on a very specific population, night shift workers, who are vulnerable to issues with DNA repair.
"These findings are very specific to night shift workers who are sleeping during the day and have lower circulating levels of melatonin," points out study co-author Parveen Bhatti, PhD, a cancer control researcher at BC Cancer Research Institute. "Non-night shift workers tend to sleep at night and usually produce adequate amounts of melatonin."
Based on the findings, it's not clear if melatonin would have the same impact if you usually sleep at night and are awake during the day.
What kind of melatonin supps should I be taking?
Dr. Winter doesn’t recommend that most people take a melatonin supplement on a regular basis, since most people produce it naturally. “Unfortunately, most people use this drug as a sleep aid, which in my opinion is an inappropriate use of the drug,” he says. However, he says there can be a place for using melatonin if you’re a night shift worker who has trouble falling asleep or if you are struggling with jet lag.
If you are interested in trying it, here are some doctor-approved supps:
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Keep in mind that supplements generally aren’t strictly regulated by the Food and Drug Administration (FDA). As a result, what the label says and what’s actually in the bottle can differ. For example, a 2017 study of 30 popular melatonin supplements found that the amount of melatonin in the bottle didn't match what the label said. The researchers also found that 26 percent of the supplements contained serotonin, a hormone that can be harmful to your health.
“The quality—and even whether the supplement even has melatonin in them—can vary dramatically,” Dr. Winter says.
That’s why he recommends buying from a reputable source, like a brand name you know and trust. Just be aware that melatonin can make you feel groggy in the morning, per Alan. "Generally, melatonin is only useful to induce sleep and is not useful to maintain sleep," she adds.
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