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What Is Melatonin & Is It Safe?

SCOFA-Melatonin-1

 
Medically reviewed by
Dacelin St Martin, MD
Triple board-certified in Sleep Medicine,
Internal Medicine, and Pediatrics.

 
 
What Is Melatonin? | How Does Melatonin Work? | The Uses of Melatonin | Melatonin & Children | Is Melatonin Safe?

 

What is Melatonin?

Melatonin is a hormone produced by the pineal gland in your brain in reaction to the darkness. It aids sleep and the timing of your circadian rhythm (the 24-hour biological clock).[1] 

Melatonin production can be disrupted by being exposed to light late at night. Although the body manufactures melatonin, it is also synthesized artificially as a food supplement to help with sleep problems. 

According to a 2012 Study by the National Institutes of Health, melatonin is one of the most used supplements by adults and children.[2]

Research also shows that melatonin may have other functions in the body besides sleeping; however, the link between melatonin and these functions is not well understood.[2]

 

How Does Melatonin Work?

The pineal gland, which is an endocrine gland in the brain, produces natural melatonin from amino acids, like tryptophan.[3] It’s released into the bloodstream and cerebrospinal fluid, allowing it to penetrate the blood-brain barrier. It acts on receptors in the brain, eye, and other body parts to regulate sleep and waking cycles.[4]

The production of melatonin increases in response to darkness. Nighttime levels are tenfold those of the daytime. The blood level of melatonin plummets significantly before dawn and is barely noticeable during the day.[1]

This rise and fall in melatonin levels signal everyone’s sleep and wake hours, also called the circadian rhythm. 

The body produces more melatonin during winter, while there is decreased melatonin production in the summer because there is more exposure to sunlight. 

Additionally, light from phones, the television, and other electronic gadgets can inhibit melatonin production when used at night, leading to sleep troubles.[5]

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The Uses Of Melatonin

Melatonin may be beneficial in many conditions. They include:

1) Jet Lag

Jet lag occurs when people travel by plane across various time zones, and one’s internal clock goes out of sync with the natural day-night cycle in the new location. 

People who suffer from jet lag may have general malaise, disrupted sleep, daytime fatigue, reduced functioning, and digestive difficulties resulting from jet lag. 

According to the findings of a study, melatonin supplements may be beneficial in resetting the sleep-wake cycle and improving sleep in those who are suffering from jet lag.[6]

2) Delayed sleep-wake phase disorder (DSWPD)

DSWPD is a sleep-wake cycle dysfunction that causes one’s sleep pattern to change. 

It often moves one’s typical sleep time by a few hours to a new time.[7] People with this disorder might find it hard to get sufficient sleep if they have tasks, like office work or school, that require them to get up early in the morning. 

Low doses of melatonin administered before night have been shown in studies to assist anyone with DSWPD move their sleep time forward.[7]

3) Shift Work Sleep Disorder (SWSD)

People who work at night can experience sleep problems due to a disrupted circadian rhythm called SWSD. 

Studies on the benefits of melatonin for shift workers were inconclusive; however, findings from the study suggest that some people can benefit from melatonin supplements.[8]

4) Insomnia

There is controversy over whether melatonin is effective in otherwise healthy individuals with insomnia, characterized by difficulty sleeping or staying asleep. 

Some sleep experts believe that melatonin might be beneficial for people with insomnia.[9] 

In contrast, others, such as the American Academy of Sleep Medicine (AASM), say that there isn’t sufficient evidence that melatonin improves insomnia.[10]

 

Melatonin & Children

Melatonin may be beneficial to children with sleeping disorders. Many research findings indicate that melatonin may aid youngsters who have difficulty sleeping to get better sleep.[11] Additionally, it may increase their total sleep duration.[12] 

According to the American Academy of Pediatrics (AAP), melatonin may be effective as a short-term therapeutic modality to assist children in adjusting to a healthier sleep pattern and establishing excellent sleep habits.[12] 

Additional studies show that melatonin may benefit children with epilepsy, attention deficit hypersensitivity disorder (ADHD), autism spectrum disorder (ASD), asthma, etc. 

Still, many experts believe that additional research is needed to determine its best use in children.[1]

 

Is Melatonin Safe?

Evidence from available studies shows that melatonin supplements for short-term therapy are generally safe for most people.[1] 

However, there isn’t enough evidence to justify its long-term use in treating sleep disorders.[13]

It’s also crucial to keep in mind the possible side effects and interactions of melatonin with other drugs, supplements, and foods. Possible side effects of melatonin include:

  • Headache
  • Nightmares
  • Somnolence
  • Nausea
  • Daytime dizziness
  • Loss of appetite
  • Joint pain

The reported adverse effects of short-term use of melatonin in kids are similar to those in adults. 

Additionally, melatonin may cause some toddlers to become agitated or more likely to bed wet. These side effects are rare if melatonin is used at low doses and for a short duration.

Even though studies suggest that melatonin is safe at low doses when taken for a short term, it’s best to consult your doctor before starting melatonin supplements to avoid any allergic reactions or hazardous combinations with other medicines. 

If you’re taking anti-epilepsy and blood-thinning drugs, you should inquire about possible drug interactions with your doctor.

 

References:

  1. “Melatonin: What You Need to Know.” National Center for Complementary and Integrative Health, U.S. Department of Health and Human Services, https://www.nccih.nih.gov/health/melatonin-what-you-need-to-know.
  2. “Using Dietary Supplements Wisely.” National Center for Complementary and Integrative Health, U.S. Department of Health and Human Services, https://www.nccih.nih.gov/health/using-dietary-supplements-wisely.
  3. Masters, Alina, et al. “Melatonin, the Hormone of Darkness: From Sleep Promotion to Ebola Treatment.” Brain Disorders & Therapy, U.S. National Library of Medicine, 2014, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4334454/.
  4. Rajaratnam SM;Middleton B;Stone BM;Arendt J;Dijk DJ; “Melatonin Advances the Circadian Timing of EEG Sleep and Directly Facilitates Sleep without Altering Its Duration in Extended Sleep Opportunities in Humans.” The Journal of Physiology, U.S. National Library of Medicine, https://pubmed.ncbi.nlm.nih.gov/15459246/.
  5. Wahl S;Engelhardt M;Schaupp P;Lappe C;Ivanov IV; “The Inner Clock-Blue Light Sets the Human Rhythm.” Journal of Biophotonics, U.S. National Library of Medicine, https://pubmed.ncbi.nlm.nih.gov/31433569/.
  6. Costello, Rebecca B, et al. “The Effectiveness of Melatonin for Promoting Healthy Sleep: A Rapid Evidence Assessment of the Literature.” Nutrition Journal, BioMed Central, 7 Nov. 2014, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4273450/.
  7. Sletten TL;Magee M;Murray JM;Gordon CJ;Lovato N;Kennaway DJ;Gwini SM;Bartlett DJ;Lockley SW;Lack LC;Grunstein RR;Rajaratnam SMW; ; “Efficacy of Melatonin with Behavioural Sleep-Wake Scheduling for Delayed Sleep-Wake Phase Disorder: A Double-Blind, Randomised Clinical Trial.” PLoS Medicine, U.S. National Library of Medicine, https://pubmed.ncbi.nlm.nih.gov/29912983/.
  8. Liira J;Verbeek JH;Costa G;Driscoll TR;Sallinen M;Isotalo LK;Ruotsalainen JH; “Pharmacological Interventions for Sleepiness and Sleep Disturbances Caused by Shift Work.” The Cochrane Database of Systematic Reviews, U.S. National Library of Medicine, https://pubmed.ncbi.nlm.nih.gov/25113164/.
  9. BL;, Matheson E;Hainer. “Insomnia: Pharmacologic Therapy.” American Family Physician, U.S. National Library of Medicine, https://pubmed.ncbi.nlm.nih.gov/28671376/.
  10. Sateia, Michael J, et al. “Clinical Practice Guideline for the Pharmacologic Treatment of Chronic Insomnia in Adults: An American Academy of Sleep Medicine Clinical Practice Guideline.” Journal of Clinical Sleep Medicine : JCSM : Official Publication of the American Academy of Sleep Medicine, American Academy of Sleep Medicine, 15 Feb. 2017, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5263087/.
  11. Wei S;Smits MG;Tang X;Kuang L;Meng H;Ni S;Xiao M;Zhou X; “Efficacy and Safety of Melatonin for Sleep Onset Insomnia in Children and Adolescents: A Meta-Analysis of Randomized Controlled Trials.” Sleep Medicine, U.S. National Library of Medicine, https://pubmed.ncbi.nlm.nih.gov/31982807/.
  12. F;, McDonagh MS;Holmes R;Hsu. “Pharmacologic Treatments for Sleep Disorders in Children: A Systematic Review.” Journal of Child Neurology, U.S. National Library of Medicine, https://pubmed.ncbi.nlm.nih.gov/30674203/.
  13. Boafo, Addo, et al. “Could Long-Term Administration of Melatonin to Prepubertal Children Affect Timing of Puberty? A Clinician’s Perspective.” Nature and Science of Sleep, Dove Medical Press, 31 Jan. 2019, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6362935/.
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