Why You May Not Want to Use Melatonin Every Night

With new studies unsure of possible side effects from long-term melatonin usage, researchers are telling people not to use the supplement for chronic insomnia.

Melatonin supplements and sleep mask on the blue background
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You climb into bed ready to turn in for the night but sleep just isn’t happening. After you’ve counted every sheep in the flock, then exhausted all other methods of relaxation to drift off naturally, your next plan of action may be to turn to a sleep aid like melatonin.

This isn’t exactly uncommon. In fact, researchers have found the use of the supplement has risen four-fold over the past decade. After all, up to 19% of American adults report sleep issues. While taking melatonin every once in a while may not be a big deal, taking melatonin nightly month after month may involve more risks than we’re aware of.

A study by the American Academy of Sleep Medicine looking into the safety of melatonin shows that research on the long-term effects of the sleep aid is limited. While investigators review the full findings, the Academy is cautioning people against using melatonin for insomnia.

Is it insomnia or are you having trouble sleeping?

What exactly is the difference between having a stretch of nights where you have trouble sleeping and insomnia? Well, they both may actually be a form of insomnia. Insomnia is broadly defined as a sleep disorder that can make it hard to fall asleep or stay asleep. Much like other sleep disorders, it exists on a spectrum from acute to chronic says Dr. Chris Winter, a neurologist, author of "The Sleep Solution" and "The Rested Child," and Sleep.com Sleep Advisor.

“It's a spectrum or a gradient. Say you had a bad night sleeping last night. Do you have insomnia? Most people would say no, you just had an isolated bad night of sleep,” Winter explains.

It’s not unusual for adults to experience short-term, or acute, insomnia. This can last one night to a few weeks. When you think of the sporadic nights where you had trouble sleeping, what you were experiencing was most likely acute insomnia. It’s very common for most people to deal with this a few times throughout their lives.

Chronic insomnia is when insomnia happens at least three nights a week for three months or more. This form of insomnia can negatively impact your everyday life. Complication of chronic insomnia include:

  • Experiencing lower job or school performance
  • Having a slower reaction time
  • Impacting your mental health
  • Higher blood pressure
  • Heart disease

Whether you have acute or chronic insomnia, if you’re not sleeping in the way you think you should be, consider consulting a health care provider. “It’s one of those things where, as a provider, I want to help you improve your sleep regardless of how acute the problem is. If you said, ‘Look I struggle with sleep and it drives me crazy,’ I'm not going to say, ‘Well come back to see me when it's three times a week to talk,’” Winter explains.

The possible dangers of using melatonin long-term

Melatonin is naturally produced in your body and helps determine the timing of your circadian rhythm. It’s released to signal to the body that it’s time to go to sleep. But this isn’t all the hormone does — it also impacts the body’s temperature, blood sugar, and blood vessel tone which is the degree of constriction experienced by a blood vessel compared to the maximum dilated state.

As with many hormones in our bodies, having too much or too little melatonin in your system long term can cause health concerns. The problem when taking a melatonin supplement is that since it’s not a drug, there’s no oversight or regulation by the FDA.

Studies have shown that melatonin products often contain inconsistent dose labeling. This makes it hard to know exactly how much melatonin you’re taking. In addition to inconsistent dosing, researchers have also found serotonin present in these products. Taking an unknown dose of serotonin for a long time can affect your heart, blood vessels, and brain. People taking medication for a mood disorder should be especially careful, as these medications already boost serotonin so an extra dose of serotonin can particularly impact them.

This increased consumption of melatonin or serotonin is mostly a risk due to the rate at which people are relying on melatonin as a nightly sleep aid. People think of melatonin as an all-natural supplement and therefore don’t think anything of taking it every day instead of taking it for occasional sleep disruptions.

There are a lot of unknowns about long-term melatonin usage due to the lack of research into the sleep aid. It’s still unknown whether it’s safe long-term for pregnant and chestfeeding people, as well as children or people with dementia.

What to know about short-term melatonin usage

Overall this study found that short-term melatonin use isn’t harmful. In fact, for certain people, it can be helpful to use on occasions when you’re trying to realign your natural sleep rhythm. “With shift work and travel, a lot of times that medication could be useful for helping to realign a strategic rhythm,” Winter explains.

But while there are seemingly no effects to taking melatonin short-term, Winter urges people with insomnia to investigate what may be causing their insomnia instead of jumping right to taking melatonin. “I think for a lot of people, the insomnia is coming from something else. It is coming from anxiety, it’s coming from a medication side effect, it's coming from spending 12 hours in bed as a 72-year-old,” Winter says. In many cases, it is more successful long-term to introduce lifestyle changes or try practices such as cognitive behavioral therapy to address underlying issues.

The full impact of melatonin as a long-term treatment is still being researched. However, moving forward many researchers are proposing melatonin be regulated more closely and be prescription-based only to avoid the over-consumption of melatonin. While awaiting the full findings and further research, talk with your health care provider about the pros and cons of using melatonin for your needs, and what other solutions exist.