• Melatonin is a hormone that naturally occurs in the body and regulates the sleep-wake cycle.
• If you are taking melatonin supplements, start by taking .5 to one milligram about two hours before bedtime.
• Some ways to increase your natural melatonin production are avoiding bright lights before bed, creating a drop in body temperature, or eating foods like milk or grapes which contain melatonin.
• This article was medically reviewed by Raj Dasgupta MD, FACP, FCCP, FAASM, Assistant Professor of Clinical Medicine with the Division of Pulmonary, Critical Care & Sleep Medicine University at Southern California (USC).

There's a reason we go to bed at night when it's dark and wake up in the morning when the sun's out, and it's not just because society says so. Our sleep-wake cycle — when we feel sleepy, and when we feel wakeful — is a part of our natural circadian rhythm, which is regulated by the body's internal clock.

Melatonin is a hormone naturally produced in the body that plays a crucial role in the circadian rhythm and our ability to fall asleep. Here's what you should know about melatonin, melatonin sleep supplements, and whether or not it can help you get a better night's rest.

Melatonin is a hormone that naturally occurs in the body

"Melatonin is a hormone that is made by the pineal gland in response to cues and signals coming from the hypothalamus, the part of the brain that has what we call the central clock," says Paolo Sassone-Corsi Ph.D., Director, Center for Epigenetics and Metabolism at University of California, Irvine. The cues telling the brain to produce (or not produce) melatonin are light and darkness.

A tiny gland in the brain called the pineal gland produces melatonin at high levels every evening in response to darkness, helping the body get ready for sleep. Melatonin levels drop significantly in the early morning hours, and the pineal gland is relatively inactive during the day, until darkness comes and the cycle repeats. According to Sassone-Corsi, melatonin has been identified as the key hormone regulating the sleep-wake cycle.

A person's natural circadian rhythm along with light and darkness are the main factors that affect natural melatonin production.

Production of the sleep hormone can be affected if the person experiences a disruption to their circadian rhythm, such as travelling to different time zones or working non-traditional hours. A 2017 study published in Biological Research for Nursing found that compared to traditional daytime workers, those on the night shift produced 33.8% less melatonin.

The amount of artificial light you look at, particularly blue light emitted from electronics, is also tied to the amount of melatonin you produce. A 2017 study published in Chronobiology International concluded blue light before bedtime is linked to suppression of melatonin production and reduced quality of sleep. This is due to blue light's short wavelengths.

If you're looking to increase your natural melatonin production, here are some things you can do.

How to naturally increase melatonin production

• Avoid light exposure at night: Stop using your blue light emitting devices two to three hours before bed if possible. Otherwise, consider getting blue light blocking glasses that can counteract the effect. Room lights should also be dimmed or turned off to kick melatonin production into gear.
• Create a drop in body temperature: One of the most effective ways to amplify melatonin production is to cause a change in core body temperature, according to Alon Y. Avidan, MD, MPH, Professor and Vice Chair in the Department of Neurology at the David Geffen School of Medicine at UCLA, and Director of the UCLA Sleep Disorders Center. "If someone gets out of the shower or a hot bath, that drop of temperature from the bath to the room's temperature is allowing for a more robust melatonin release, he says. Similarly, turning the heat down in your bedroom to fall asleep in a cooler environment can do the trick, too.
• Eat foods containing melatonin: Melatonin has been discovered in many foods. A 2017 study published in Nutrients reported detectable levels of melatonin in milk, some fruits (grapes, cherries, and strawberries), seeds, legumes, and nuts (pistachios appear to have the highest levels of melatonin than other nuts).

Melatonin supplements are used to promote sleep

Melatonin supplements are a more natural way to promote sleep, as opposed to taking hypnotics such as Ambien or benzodiazepines like Klonopin. According to Avidan, melatonin supplements promote sleep by raising your melatonin levels as the hormone enters your bloodstream, blocking the "alerting effect" of the circadian clock. Prescription sleeping pills work completely differently by binding to receptors in the brain that promote sedation.

In general, research surrounding the effectiveness of melatonin for sleep has been promising. A 2013 meta analysis published in PLOS One determined that among 19 studies and 1683 subjects, participants taking melatonin rather than a placebo fell asleep about seven minutes faster and slept for about 8 minutes longer. More recently, a 2017 review in Neurological Research also concluded that melatonin supplements can help people fall asleep faster as well as improve quality of sleep.

While plenty of research has been conducted on melatonin, there are still a lot of unknowns when it comes to the effectiveness, dosing, and safety of melatonin. According to Avidan, there's no universal dose of melatonin that will be effective for everybody — and not everybody will feel the effect of melatonin. If melatonin doesn't help you fall asleep, it's possible you need a higher dose, or, that your sleep troubles are caused by something else.

How to take melatonin

Dosing varies depending on the person. A low dose of melatonin is considered .5 milligrams to one milligram, which Avidan says can be enough to adjust somebody's circadian pattern in the case of situations like jet lag or daylight savings.

If someone is really struggling to fall asleep, they might need to move up to a three milligram dose, which can be considered the "hypnotic dose."

Certain conditions may call for even higher doses. "High doses between five to 15 milligrams are available for people who have a certain parasomnia – an abnormal behavioral activity that occurs during sleep, for example, sleepwalking," Avidan says. However, a dose of five milligrams or more should not be taken without approval from your doctor.

As far as when you should be taking it, be sure to take a melatonin supplement about two hours before your desired bedtime. Since melatonin affects circadian rhythms, it is important to avoid taking it too late at night. For example, taking melatonin at 3am after tossing and turning could throw off your sleep schedule and affect your rest for the remainder of the week.

Just remember that melatonin is most effective when combined with a regular bedtime schedule and good sleep hygiene.

It is impossible to overdose on melatonin since toxic levels of melatonin [that put life at risk] have never been registered," says Lorenzo Franceschetti M.D., a researcher at the University of Milan, who has conducted extensive studies on melatonin. He says unpleasant side effects can occur when taking high doses of melatonin, but that's about the extent of it. Possible common side effects of melatonin include nausea, dizziness, and headaches. Taking too much can also result in next day drowsiness or a disruption in your circadian rhythm.

However, both Avidan and Sassone-Corsi say we don't have enough concrete evidence to say what dose is unsafe, or what particular groups of people melatonin may be unsafe for. For example, we don't have sufficient evidence surrounding taking melatonin during pregnancy to say if it's safe or not.

"We don't know enough yet. I will not say that it's dangerous, but I would use some caution," Sassone-Corsi says. It is possible for melatonin to interact with prescription drugs, so if you take any medications, be sure to check with your doctor to make sure the supplement is safe for you.

Something else to keep in mind is the fact that the FDA doesn't regulate melatonin, since it's a supplement and not a drug. This means that the supplements you're taking might not be the dosage you think. According to Avidan, a lot of doses are inconsistent with what the bottle says.

The people who would benefit the most from taking melatonin, according to Avidan are

• People dealing with jet lag
• Alzheimer's or dementia patient's dealing with insomnia due to neurodegeneration
• People with parasomnia (abnormal sleep behaviors REM movement disorder, for example)
• People with delayed sleep phase syndrome (DSPS) – which usually occurs in preteens and teens going through puberty

Other health benefits of melatonin

As more research is conducted surrounding melatonin, scientists are finding more uses for melatonin – and they aren't just surrounding sleep. "Regarding health conditions, melatonin can be called a 'Swiss army knife' since it can impact every cell of the human body," Franceschetti says. However, it is important to note that these uses are very experimental and, especially as a treatment for dementia or as an anti-inflammatory agent, melatonin has not been used in clinical practice.

In a 2017 study that he co-authored, published in the International Journal of Endocrinology, Franceschetti and his team concluded melatonin can act as an anti-inflammatory and an antioxidant, protecting cells from damage and death. Free radicals (atoms or molecules that are highly reactive) can cause cellular death and lead to various health conditions, and antioxidants can prevent it – and that's where melatonin comes in.

"Because of the ability to neutralize radicals, melatonin can defer age-related dysfunction of several organs, such as the heart, for example," Franceschetti says.

Some other possible uses for melatonin are:

Endometriosis pain relief: People who suffer from endometriosis, a uterine disorder that causes chronic pelvic pain, can get relief with melatonin due to its anti-inflammatory effects. A 2013 study published in Pain found that 10 milligrams of melatonin was more effective than a placebo in reducing daily pain by 39.80%, and were less likely to use other pain relievers.

IBS treatment: Since the gut has melatonin receptors, research has been conducted to see if melatonin can help stomach conditions, such as IBS, and the findings are promising. A 2014 review published in World Journal of Gastroenterology concluded that those who took melatonin versus placebo in various studies did experience some relief from abdominal pain, and that the anti inflammatory properties can reduce intestinal inflammation.

Reduce cancer risk: Sassone-Corsi says melatonin can possibly act as an anti-tumor agent and may prevent certain types of cancer, though there's not enough research to say for sure. However, a 2018 review published in the International Journal of Endocrinology said that upon analysis of multiple studies in humans and rats, melatonin seems to have anti-tumor effects in hormone dependent cancers: ovarian cancer, breast cancer, and prostate cancer.

Lower risk of Age-Related Macular Degeneration (AMD): According to a 2016 review published in Oxidative Medicine and Cellular Longevity, melatonin can counteract the oxidative stress on the eyes that may get worse with age, due to its antioxidant properties. They note one study where participants with AMD took three milligrams of melatonin nightly for three months. After the three months, their vision remained stable.

It's an exciting time in science where we are learning a lot more necessary information about melatonin and its uses. Hopefully, more research will continue to be conducted to get some concrete answers regarding long term safety and effectiveness of melatonin supplements.

If you're having trouble falling asleep, consult your doctor before you buy melatonin supplements and start taking them. But once you get the green light, it could be lights-out and sweet dreams.

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