What is melatonin and does it work?

For optimal health and wellbeing, most adults need seven to nine hours of sleep a night, however it's safe to say not all of us get this optimal amount of sleep.

From work stress to parenting, or sleep problems like insomnia, many of us face roadblocks to getting the amount of sleep we want, or good quality sleep. With research suggesting that people who get sub-optimal sleep are more likely to experience challenges with weight management, mental performance- and that over the long term sleep loss may raise a person’s risk of developing health conditions such as heart disease, depression, and cancer - understandably many sleep sufferers look for relief.

Melatonin is a sleep supplement. It's a synthetic form of the body’s naturally occurring melatonin, a hormone produced in the brain that helps regulate sleep-wake cycles.

Commonly referred to as “the sleep hormone,” melatonin is produced in the brain’s pineal gland. It helps regulate the body’s circadian clock (24-hour sleep-wake cycle), helping you fall asleep at night and wake up in the morning.

The body’s production of melatonin rises as day transitions to night, a biological response to fading light levels, says Ellen Vora, MD, a holistic psychiatrist who frequently counsels patients on natural ways to improve sleep quality. In the morning, melatonin production decreases in response to daytime light exposure, which helps you wake up.

Certain factors can impair the body’s production of melatonin and interfere with sleep. Night-time exposure to the light of smartphone screens, TVs, and certain lightbulbs is one. Age is another factor. “As we age, the production level of melatonin tends to go down, which could be why some older folks tend to have difficulty falling asleep and maintaining sleep,” says Kannan Ramar, MD, a sleep physician at the Mayo Clinic and president-elect of the American Academy of Sleep Medicine (AASM).

So do melatonin supplements really work to improve sleep? Here’s what you need to know:

The research is mixed on the effectiveness of melatonin supplements for sleep. The data is also inconclusive on when and where melatonin might best be used, Ramar says.

That said, short-term use of melatonin (under three months) generally appears to be safe, and some research suggests that people with certain types of sleep disorders may benefit from taking a supplement, provided they take it at the right time, at the appropriate dose, and for the specific issue they’re addressing.

Because melatonin tells your body what time of day it is, it may be helpful in alleviating sleep problems associated with an out-of-sorts body clock, such as jet lag or delayed sleep disorder. It may also be beneficial in helping older adults get better sleep.

Here’s a closer look at the research on melatonin for a variety of sleep-related issues:

When it comes to melatonin’s ability to alleviate insomnia—a sleep disorder characterised by trouble falling asleep, staying asleep, or both—the jury is out. A 2013 meta-analysis found that subjects with insomnia who took melatonin fell asleep about seven minutes faster, slept longer, and had better overall sleep quality than those who took a placebo. But other research, such as a small 2003 study of patients with primary insomnia published in theJournal of Psychiatry & Neuroscience, found no benefit.

When travelling across time zones (something we're not doing much of at the moment), many people experience jet lag, a disruption to the body’s internal clock that can make falling asleep (and waking up) in accordance with local time difficult. A 2014 research review found that melatonin may be better than a placebo at alleviating jet lag after both eastward and westward flights.

If your job requires you to work the overnight shift, you may find yourself struggling to fall asleep when you need to- that is, during the day. Could a melatonin supplement help you drift off? To date, studies on shift work and melatonin have been small or inconclusive, according to the National Institutes of Health (NIH). For example, one 2014 research review found that workers with non-traditional hours who took melatonin after a shift slept about 24 minutes longer than those who took a placebo. That said, only 263 subjects were studied, and factors such as the time it took to fall asleep were no different between groups. The researchers described their findings in support of melatonin as “low-quality evidence”.

Delayed sleep disorder, or delayed sleep-wake phase disorder (DSWPD), occurs when the body clock tells a person to fall asleep later and wake up later than they’d like to - think sleeping from 3am to 11am. For people wanting to transition to an earlier sleep schedule, supplementing with melatonin may be helpful, Ramar says.

While evidence is mixed, it leans toward the positive. “There’s some data that suggests one could take a [standard] dose of melatonin - usually 0.1 mg to 0.5 mg at the most - about four to five hours before the desired sleep time,” Dr. Ramar explains. So if you’re prone to lying awake until 2am when you really want to be asleep by 10pm, taking melatonin between 5 and 6pm may help.

While melatonin supplements mimic a hormone naturally found in the body, researchers have yet to draw definitive conclusions about any side effects associated with extended use.

Short-term use of under three months appears to be safe, according to the NIH. A 2015 review on the safety of melatonin supplements published in the journal Clinical Drug Investigation found that mild adverse side effects can include headaches, dizziness and nausea.

If you’re currently taking any medications or other supplements, it’s best to check with your doctor for potential interactions before incorporating melatonin into your lifestyle. Melatonin may have negative interactions with blood thinners, blood pressure medications, contraceptives, diabetes medications, immunosuppressants, and other drugs, according to the Mayo Clinic.

Research suggests that melatonin may be helpful in optimising the internal body clock (circadian rhythm) and promoting better rest, particularly for adults dealing with jet lag, delayed sleep disorder, or a short-term bout of insomnia. Overall, however, research supporting melatonin’s use is mixed, and side effects are possible.

Practising good sleep hygiene is an important part of improving sleep duration and quality. Examples of sleep-promoting habits include: maintaining a consistent bedtime, getting exposure to light during the day, and limiting exposure to the light of electronics in the hour or so prior to bedtime.