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What Happens If You Take Melatonin Every Night Before Bed

Usage is on the rise—here's what doctors have to say about its safety.

When you're suffering from insomnia, anything that helps you fall—and stay—asleep comes as much-needed relief. That's why, increasingly, people are reaching for melatonin supplements. These synthetic hormones work by mimicking naturally occurring hormones produced by the pineal gland in the brain. This helps regulate your circadian rhythm in response to darkness. A 2018 study found that people now take melatonin at twice the rate they did a decade before the start of the study.

However, doctors say that melatonin supplements are not intended for long-term use, and can come with some unintended consequences when you take them every night before bed. "Melatonin should only be used to recalibrate a circadian rhythm that has gone awry, such as with jet lag, for a short period of time," Nilong Vyas, MD, the pediatrician behind Sleepless in NOLA and a medical review expert for, tells Best Life.

The Mayo Clinic adds that melatonin should never be used as the "first or only remedy" for poor sleep. "It needs to be coupled with lifestyle choices that create a solid foundation for good health," their experts write. Read on to learn what happens when you take melatonin every night, and what experts say is safe usage of the popular supplement.

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You may experience certain side effects.

A man holding his head with his eyes closed suffering from a headache
iStock / stefanamer

The good news when it comes to melatonin is that you are unlikely to develop a tolerance or physical dependency, the Cleveland Clinic writes. However, some people will develop side effects after taking melatonin long-term.

"Melatonin is generally considered safe for short-term use, but long-term use or high doses may lead to potential side effects," explains Blen Tesfu, MD, a general practitioner and medical content creator for Welzo. "Common side effects can include headaches, daytime sleepiness, dizziness, stomach discomfort, and irritability," she says, noting that these tend to be relatively mild.

The Mayo Clinic adds that rarer side effects can include vivid dreams or nightmares, feelings of depression, irritability, stomach cramps, other gastrointestinal problems such as diarrhea or constipation, increased fall risk, mood swings, and more.

Tesfu notes that each person taking melatonin may respond differently to the supplement. "Some people may experience side effects or changes in efficacy even with short-term use, while others may not," she says.

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It could interact with your other medications.


If you take melatonin every night as a sleep aid, you may also increase your risk of the supplement interacting with your other medications.

The Mayo Clinic notes that certain types of medication may be more likely to cause interactions. These include medicines that slow blood clotting, prevent seizures, manage blood pressure, manage diabetes, or suppress the immune system.

Their experts add that any medicine that is broken down by the liver has the potential to interact with melatonin. Speak with your doctor or pharmacist to find out if your medications are safe to take with short-term doses of melatonin.

It could interfere with your normal hormone production.

Female doctor therapist in white uniform with stethoscope consulting woman patient at meeting, sitting at desk in hospital, giving recommendations, explaining medical checkup results at appointment
fizkes / Shutterstock

Scientists are still working to understand the ways that taking melatonin regularly could impact your normal hormone production—especially in younger users.

"Because melatonin is a hormone, it's possible that melatonin supplements could affect hormonal development, including puberty, menstrual cycles, and overproduction of the hormone prolactin, but we don't know for sure," says the National Center for Complementary and Integrative Health (NCCIH), a branch of the National Institutes of Health (NIH).

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Here's how much is safe to take.

Aisle of Melatonin
The Image Party/Shutterstock

How much melatonin you take and for how long can vary depending on an individual's needs and circumstances, Tesfu says. The key is to consult with a healthcare professional, such as a doctor or sleep specialist, before starting melatonin or any sleep aid. "They can provide personalized guidance based on your specific situation and help determine the appropriate dosage, duration, and potential interactions with other medications you may be taking," the doctor tells Best Life.

However, melatonin is generally considered safe to take for a few nights or up to several weeks until sleep patterns normalize. The U.K.'s National Health Services (NHS) says that if you're taking a low dose of 2mg, slow release tablets, you should never exceed a total of 13 weeks of regular use unless you are advised otherwise by your doctor. Higher doses may need to be even more limited in duration.

For a better night's rest, focus on creating good sleep hygiene practices, such as maintaining a consistent sleep schedule, creating a relaxing bedtime routine, and optimizing the sleep environment, Tesfu advises. These can contribute to improving sleep quality without relying solely on sleep aids.

Best Life offers the most up-to-date information from top experts, new research, and health agencies, but our content is not meant to be a substitute for professional guidance. When it comes to the medication you're taking or any other health questions you have, always consult your healthcare provider directly.

Lauren Gray
Lauren Gray is a New York-based writer, editor, and consultant. Read more
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