Melatonin Side Effects to Recognize

Sometimes described as a melatonin 'hangover'

Melatonin side effects, sometimes referred to as a melatonin "hangover," are usually mild. Most often, they include headaches, dizziness, nausea, and sleepiness. Though short-term usage appears safe, research on long-term use and side effects remains limited.

This article explains the side effects and risks of melatonin and its alternatives.

A woman holding a sleep aid pill before bedtime

Tero Vesalainen / Getty Images


Speak with your healthcare provider before taking melatonin to ensure it will not interact with any medications you are currently taking.

What Are the Side Effects of Melatonin?

Melatonin can produce side effects, and some are more common than others. Common side effects include:

Uncommon side effects may include:

Research has not found severe or life-threatening side effects. However, there is little research on the long-term risks associated with melatonin.

Dosage Evaluated in Research

In a systematic review of 37 randomized controlled trials, daily melatonin doses ranged from 0.15 milligrams to 12 milligrams.


Children

Discuss with your healthcare provider or pediatrician before giving melatonin to children. Researchers found that melatonin overdosing is the most significant risk to kids and adolescents.

Melatonin was the most frequently ingested substance among children reported to poison control centers in 2020, and between 2012 and 2021, there were more than 260,000 pediatric melatonin ingestions. Most teen hospitalizations resulted from intentional ingestion, whereas hospitalizations for kids under 5 were primarily for unintentional ingestion.

Though melatonin is increasingly prescribed for children, it is not registered for use in children, nor has it undergone formal safety testing in this population.

Young, Middle-Age, and Older Adults

For most adults, melatonin has minimal and mild side effects. However, older people need to be careful with melatonin because it presents different risks in this population. One study found that older people who are more prone to falls may be at a higher risk of fractures when taking melatonin.

Another study found melatonin supplementation in older people with dementia increased withdrawn behaviors and should be avoided.

Melatonin Use in Pregnancy and Lactation

More research is needed on melatonin during pregnancy and breastfeeding. If you are pregnant or lactating, discuss melatonin with a healthcare provider before taking it.

Is It Safe to Use Melatonin Every Night?

Melatonin is intended for short-term use, so you should not use it daily for an extended period unless directed by a healthcare provider. Long-term side effects of melatonin are not well studied and are, therefore, relatively unknown.

Dependency: Possible or Unlikely?

Though melatonin does not cause withdrawal symptoms or create chemical dependency, you may rely on it as a crutch to get or stay asleep. Unfortunately, this may get in the way of getting to the bottom of why you are struggling with falling asleep in the first place.

Because melatonin is intended for short-term use, it's best to use it occasionally. Talk to a healthcare provider for diagnosis and treatment if you have insomnia symptoms.

Adjusting Your Melatonin Dose

Melatonin consumption in daily doses greater than 5 milligrams (mg) more than tripled between 2005 and 2018. Researchers believe this raises safety concerns because supplements may contain up to 478% higher melatonin content than labels indicate.

Your body produces melatonin naturally at around less than 0.3 mg a day. It's best to take the lowest effective dose possible to mimic the natural state in your body. For adults, 0.5–5 mg is the standard dose. In older adults, doses between 1 mg and 6 mg were effective for improving sleep in older adults.

Most children respond to a low dose of 0.5–1 mg. However, talk to a healthcare provider before giving melatonin to children.

What Else to Try for Sleep

In addition to melatonin, there are numerous methods for helping you sleep. Good sleep habits (sleep hygiene) are sometimes your best bet. These habits include:

  • Going to bed and getting up at the same time every day
  • Keeping your bedroom comfortable and relaxing
  • Limiting or not using mobile devices in the bedroom
  • Avoiding large meals and alcohol before bed
  • Being physically active during the day

If you have trouble falling asleep, get up after 20 minutes of trying and engage in a quiet activity in low light before trying again. Cognitive behavioral therapy (CBT) for insomnia is the most effective long-term treatment for this sleep disorder.

Summary

Melatonin has some potential side effects that are usually mild. These most often include headache, dizziness, nausea, and daytime sleepiness. The most significant risk for children is accidental overdose; therefore, always discuss melatonin for a child with a healthcare provider first. Older adults may be at risk of falls and fractures when taking melatonin. Those with dementia are advised to avoid melatonin due to the risk of increased withdrawal behavior. Melatonin is intended for short-term use, and long-term risks are not well studied.

Frequently Asked Questions

  • What are some strange side effects of melatonin?

    Some less common melatonin side effects include agitation, fatigue, mood swings, nightmares, skin irritation, and palpitations. More commonly, people experience melatonin "hangover," with symptoms like headache, daytime sleepiness, and nausea.

  • Which medications cause side effects with melatonin?

    People taking medications for epilepsy and blood thinners need to be careful with melatonin. These medications may interact with melatonin. Therefore, always talk to a healthcare provider before taking the supplement.

  • When do melatonin side effects wear off?

    Melatonin starts working in 20–40 minutes, peaks after an hour, then goes down in four to eight hours. It's a good idea not to drive or use machinery for four to five hours after taking melatonin.

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Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Kathi Valeii
As a freelance writer, Kathi has experience writing both reported features and essays for national publications on the topics of healthcare, advocacy, and education. The bulk of her work centers on parenting, education, health, and social justice.