Surprising Side Effects of Taking Melatonin Supplements, Says Science — Eat This Not That


Melatonin is a hormone naturally produced in the body that helps regulate sleep. It is often taken as a supplement to help people fall asleep faster and stay asleep longer. While melatonin is generally considered safe, there are some surprising side effects that have been linked to taking melatonin supplements, according to recent scientific research. In this article, we will explore some of the potential side effects of taking melatonin supplements and provide tips on how to minimize them.

Surprising Side Effects of Taking Melatonin Supplements, Says Science

Melatonin supplements are widely used to help people fall asleep faster and stay asleep longer. But according to recent research, taking melatonin supplements may have some unexpected side effects. Here’s what you need to know.

1. It May Interfere With Your Natural Sleep Cycle

One of the most common side effects of taking melatonin supplements is that it can interfere with your body’s natural sleep cycle. This is because melatonin is a hormone that helps regulate your body’s circadian rhythm, or internal clock. When you take melatonin supplements, it can throw off your body’s natural rhythm, making it harder to fall asleep and stay asleep.

2. It May Cause Headaches and Dizziness

Another potential side effect of taking melatonin supplements is headaches and dizziness. This is because melatonin can cause a drop in blood pressure, which can lead to headaches and dizziness. If you experience these symptoms, it’s best to stop taking the supplement and talk to your doctor.

3. It May Cause Stomach Upset

Taking melatonin supplements can also cause stomach upset, including nausea, vomiting, and diarrhea. This is because melatonin can affect the digestive system, leading to these symptoms. If you experience any of these symptoms, it’s best to stop taking the supplement and talk to your doctor.

4. It May Interfere With Medications

Finally, taking melatonin supplements can interfere with certain medications, including blood thinners, birth control pills, and antidepressants. If you’re taking any of these medications, it’s best to talk to your doctor before taking melatonin supplements.

Overall, melatonin supplements can be a helpful way to get a better night’s sleep. But it’s important to be aware of the potential side effects, and talk to your doctor if you experience any of them.

Melatonin is a hormone that is produced in the brain. It regulates the body’s circadian rhythm, hormones secreted by the endocrine system, and sleep patterns.

Experts may recommend a melatonin supplement for certain conditions like jet lag or insomnia, but those supplements are synthetically made in a laboratory. (For natural sleep-supporting supplements, check out these 5 Absolute Best Foods to Eat For Better Sleep.) Usually, the supplements come in pill form, but they can also be found in a form that you place in the cheek or under your tongue so it gets absorbed quickly into the body.

If you’re looking to take melatonin, here are 5 side effects that you may experience.

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Some folks have trouble falling asleep at a usual bedtime. Research shows that taking melatonin supplements can help reduce the length of time young adults and kids fall asleep (in those who have trouble falling asleep). It should be noted that this supplement is not regulated by the Food and Drug Administration (FDA) and should only be used in children and adults after speaking with a medical doctor.

Woman using a laptop at home stops, her hand to her head.

If you take melatonin during the day, it can cause sleepiness. This is why when you take it matters. It is advised not to drive or use machinery for 4 to 5 hours after taking the supplement.

Middle aged woman suffering from abdominal pain while sitting on bed at home

When taken orally, melatonin has been reported to have side effects like nausea, abdominal cramps, mild abdominal pain, diarrhea, decreased appetite, and/or constipation. Oftentimes these symptoms happen within the first few days of taking the supplement and then subside after a few days.

READ MORE: The Best Supplements for Digestion, According to Dietitians

Man sitting on bed holding his head.

When taken orally, melatonin has been reported to cause migraine-like headaches or dizziness, especially during the first few days. The symptoms tend to be more common when melatonin is taken in the morning or at high doses (greater than 50mg).

happy young woman in bed with white sheets stretching in front of windows in morning
Shutterstock / Nenad Aksic

Taking 2 to 3 milligrams of melatonin daily when traveling to a different time zone seems to improve alertness and reduce daytime sleepiness in those with jet lag. There is also some evidence that melatonin supplements may help improve other jet lag symptoms including fatigue.

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Toby Amidor, MS, RD, CDN

Toby Amidor is an award winning dietitian and Wall Street Journal best-selling cookbook author who believes healthy and wholesome can also be appetizing and delicious. Read more