The Dark Side Of Melatonin: Not A Magic Bullet For Sleep

Feb 23, 2017 //

Over the last two decades, melatonin — marketed as an all-natural sleep aid — has earned a spot in medicine cabinets across the country. Cheap, readily available, and considered safe by many, melatonin is often considered to be an all-natural way to help you catch some zzzs. As a result, many of us, including regular travellers and those with trouble sleeping, pop milligrams of melatonin without thinking twice.

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But is melatonin really as safe as they say? And is it being used correctly? Here, we look into the dark side of melatonin and debunk some myths over the “harmless” supplement.

What Is Melatonin?

Melatonin is a hormone which is present in the body naturally, produced by the pineal gland in the brain. Melatonin can be stimulated by light and suppressed in the darkness, suggesting the importance of the hormone in regulating sleep cycles and other important bodily functions. Levels of melatonin are also known to be at their highest right before bed time, which is why many people turn to melatonin supplements at night to help them sleep.

It won’t kill you, but it’ll make your life pretty miserable.”

However, this does not mean that melatonin makes you sleep. According to Dr. Oz: 

“Melatonin is a sleep and body clock regulator – NOT a sleep initiator. Melatonin works with your biological clock by telling your brain when it is time to sleep. Melatonin does not increase your sleep drive or need for sleep.”

In order to use this hormone as a medicine, it must be produced in a laboratory setting. Synthetically-produced melatonin supplements can be used to treat disorders involving the sleep cycle.

The problem is that melatonin is classified as a dietary supplement rather than a medication, and isn’t regulated.

Uses Of Melatonin

Melatonin is known to be effective in correcting sleep-related and has been found to be effective in treating sleep disorders in people who have impaired vision.

Research has also shown for melatonin to be effective in correcting some symptoms of jet lag, such as those of coordination problems and alertness, along with tiredness and daytime sleepiness. However, melatonin is not effective when it comes to shortening the period of time it takes for a jet-lagged person to fall asleep.

Side Effects Of Melatonin

The problem with melatonin lies in the lack of understanding about proper dosages. Because melatonin is is labelled a dietary supplement (rather than a drug), companies can sell supplements at any dosage they like, with varying amounts.

Researchers have concluded that the correct dosage for melatonin falls between .3 and 1 mg, yet it’s standard for many sleep aids to contain as much as 10 times that amount.

Melatonin is a sleep and body clock regulator – NOT a sleep initiator.”

This can result in some nasty side effects — as well as some more serious ones.

Of the common side effects of melatonin, irritability, sleepiness, drowsiness, fatigue, dizziness and headaches are a few.

Disorientation, confusion, coordination difficulties, sleep walking, nightmares and vivid dreams have also been noted as possible side effects of melatonin, with these melatonin side effects wearing off after the cessation of the administration.

To be fair, it has not been confirmed whether these side effects are the already existing side effects of lack of sleep or jet lag, the two main reasons for the administration of melatonin, or whether they are of the hormone itself, but researchers suspect that there is a link, especially in dosages that exceed the recommended amount.

The issue is exacerbated in some less common, but more serious side effects.

Gastrointestinal Side Effects

Other side effects of melatonin include gastrointestinal issues such as diarrhea, abnormal feces, stomach pain, vomiting, nausea, cramping, increased appetite or altered tastes.


Research has shown that melatonin can lead to seizures especially in children suffering from neurological disorders severe in nature. However, other studies have concluded the exact opposite results, whereby the administration of regular suggested doses of melatonin decreased the risk of seizures. This particular possibility of melatonin side effect is still a controversy. However, it is safe to say the administration of melatonin in those with neurological disorders should be monitored closely by a professional.

Mood Changes

Another potential side effect of melatonin can be mood changes, including sadness and giddiness. Overdose of the melatonin pill can lead to hallucinations and paranoia as well.


Bleeding is another possible side effect of melatonin. Those individuals who have disorders which may cause bleeding should be extremely careful along with those who are on pills which may have bleeding already as side effect, when taking this hormone pill.

Cholesterol Increase

Another side effect of melatonin that has been noted is the possibility of an increase in blood pressure. Hence, it is necessary that caution is practiced in those cases where cardiovascular disease runs high and high cholesterol levels are an issue.  Furthermore, abnormal heart rates have also been associated with the use of melatonin.

Pregnancy-Related Side Effects

Melatonin side effects may also involve those which can hinder the process of pregnancy. Melatonin may interfere with other hormones which can cause issues during pregnancy or cause hindrances when trying to get pregnant. Developmental problems in the fetus may be triggered in cases of high levels of melatonin existing in the body, so it is not recommended that women take melatonin while pregnant.

Not A Regular Sleep Aid

Although many see melatonin as a miracle cure for insomnia, it may actually do just the opposite, and promote insomnia over time. “Taking melatonin for an extended period of time your body may acclimate and re-adjust and produce less over time which will work against you,”  says Michael Grandner, a sleep researcher at the University of Pennsylvania.

You’re better off using melatonin rarely, for example, when readjusting to jet-lag, rather than to help you sleep — and never as a regular sleep aid.

Read Your Labels

Due to the lack of regulation, it’s easy to take too much melatonin and suffer the unfortunate side effects as a result. While there’s no evidence to suggest that melatonin can be extremely harmful or fatal, it is a hormone, and can therefore upset your body’s natural processes.

“With some hormones, if you take too much you can really put your body in danger,” says MIT neuroscientist Dr. Richard Wurtman, who first introduced melatonin as a sleep aid 20 years ago. “With melatonin, you’re not in danger, but you’re also not very comfortable. It won’t kill you, but it’ll make your life pretty miserable.”

More importantly, it should not be given to children, as it can affect hormonal development.

The next time you find yourself reaching for a melatonin tablet to help you sleep, read the label and make sure the dosage is under the recommended amount.

Better yet, consider taking melatonin discerningly, if at all. Instead, get some exercise, turn off your electronic devices, have a cup of chamomile tea and get some sleep — the all-natural way.