What is melatonin, how does it work, and what are the risks?

What is melatonin, how does it work, and what are the risks?

Melatonin has been considered one of the better, natural sleep aid options in the US for a long time. But what exactly is it, and what side effects come with taking this hormonal supplement to help with our sleep?


What is melatonin?

Melatonin is a naturally occurring hormone released at night by your pineal gland in response to darkness, acting on receptors in your body to encourage sleep. Melatonin plays an important role in helping us regulate our circadian rhythms, and can be blocked, making us feel less tired, by the presence of excess light at night. 


How does melatonin work?

Melatonin is released naturally by our bodies at night when there is less light, making us tired and signaling to our bodies that it is time to rest and sleep. When our eyes receive light from the sun (or other sources), the production of melatonin is stopped by our pineal glands, encouraging us to become alert and stay awake. 

Melatonin is most significantly associated with regulating our sleep-wake cycle. As infants, our melatonin levels become regular about 3 months after birth, and as we become teenagers, the natural schedule of our melatonin release becomes delayed, yielding later sleep and wake times as we age.

In addition to ruling our sleep-wake cycles, melatonin also helps regulate blood pressure levels, body temperature, cortisol levels, and immune function.

Melatonin is often taken as a supplement to stimulate the drowsy effects we’d get from our pineal glands naturally releasing the hormone. However, while adults produce between 10 and 80 micrograms of melatonin a night, taking over-the-counter melatonin can raise your levels of melatonin a thousand times as much, with most doses ranging from .3 to 60 milligrams.



What does melatonin help relieve?

Those suffering from jet lag, insomnia, anxiety, and other sleep disorders often turn to melatonin for its sedating properties. However, research around whether melatonin relieves insomnia has been inconclusive. 


Who might benefit from taking melatonin or other sleeping pills?

The Centers of Disease Control and Prevention called the sleep crisis a public health epidemic, affecting 1 in 3 adults in the United States, with the percentage of teens who suffer from insufficient sleep in the US falling even higher.

Sleep problems are incredibly common among Americans; studies have found 70% of adults in the US suffer from insufficient sleep at least once a month. Another study from the CDC found that 25% of adults report insufficient sleep at least 15 nights every 30 days. Other research estimates that 50-70 million Americans struggle with sleep related problems.


What are the risks of taking melatonin?

Because melatonin is classified as a supplement instead of a drug, it isn’t regulated by the Food and Drug Administration. Studies have found that melatonin labels and the doses they claim to contain don’t always add up. The American Academy of Sleep Medicine reported in one study evaluating 31 different OTC melatonin supplements that 70% of the brands they tested contained the wrong amount of melatonin as advertised. Doses varied from 83% less to 478% more melatonin than the labels showed. That’s quite the difference!

The CDC reported that in the last 10 years, there was a 530% increase in the number of children taking melatonin. 27,795 of those cases resulted in hospital and other health care facility visits. While melatonin is considered generally safe to take short term, some studies have raised worries that it could affect hormone development in adolescents. Experts agree more long-term studies are needed to verify melatonin’s safety for use in children, but reported side effects for children include drowsiness, headaches, dizziness, and agitation.

While melatonin is available over-the-counter in the United States, users need a prescription in most European countries. Additionally, it’s generally only approved for use in older adults with sleep disorders.


What are the side effects of taking melatonin and other sleeping pills?

80% of all sleep medicine users report feeling hangover effects after taking sleeping pills. This can include drowsiness, dizziness, brain fog, and even balance problems. Other OTC and prescription sleeping pills have been also associated with headaches, muscle weakness, digestive problems, and more.

Studies around melatonin’s side effects compared to other sleeping pills have been generally inconclusive. Additionally, further research into whether melatonin supplements reduce the natural production of the hormone in our bodies is needed. 

Other concerns around melatonin’s side effects include blood thinning, and negative impacts on memory and muscle performance when taken along with other sleeping pills. 


Is melatonin addictive? Can you build a tolerance to melatonin?

Many sleep aids are considered habit forming and addictive. Melatonin is no exception in this case. Sleep medications, when taken habitually or night after night can cause our bodies to build up dependences, and even tolerances. When taking strong sleeping aids with habit forming elements and ingredients, your body can expect to get used to a pill to get to sleep. When looking for effective sleep aids, it’s best to try to steer away from hormonal options and pills that contain artificial chemical ingredients.


How can you increase melatonin levels naturally?

To encourage the promotion of melatonin naturally, experts recommend the following:

  • Reduce light exposure, screen time, and dim any necessary light sources in the evenings.
  • Boost your body’s natural sleep-wake cycle by exposing yourself to as much natural light as possible during the day, especially starting with the morning. 
  • Try to not rely on melatonin supplements for the hormone’s naturally sedating effects.
  • Stick to a regular sleep schedule when possible to help your body get used to a consistent sleep-wake cycle.


Where can I learn more about melatonin?

Check out the articles below from Slate, Healthline, and more for further info on the studies and details on melatonin referenced above.




Arnarson, BSc PhD, Atli.“Side Effects of Melatonin: What Are the Risks?” Healthline, Healthline Media, 3 Apr. 2022, https://www.healthline.com/nutrition/melatoninside-effects#TOC_TITLE_HDR_3.

Citroner, George.“People Are Taking High Doses of Melatonin to Sleep.” Healthline, Healthline Media, 3 Feb. 2022, https://www.healthline.com/healthnews/people-are-taking-highdoses-of-melatonin-to-sleep-whyexperts-are-concerned.

Lelak, Karima. “Pediatric Melatonin Ingestions — United States, 2012–2021  | MMWR.” Centers for Disease Control and Prevention, U.S. Department of Health & Human Services, 2 June 2022, https://www.cdc.gov/mmwr/volumes/71/wr/mm7122a1.htm?s_cid=mm7122a1_w#contribAff.

“Melatonin - Wikipedia.” Wikipedia, Wikimedia Foundation, Inc., 31 July 2003, https://en.wikipedia.org/wiki/Melatonin#Circadian_rh.

“Melatonin: What You Need To Know | NCCIH.” NCCIH, National Center for Complementary and Integrative Health, Jan. 2021, https://www.nccih.nih.gov/health/melatoninwhat-you-need-to-know.

“Sleeping Pills: Types, Side Effects & Treatment.” Cleveland Clinic, Cleveland Clinic, 27 Apr. 2021, https://my.clevelandclinic.org/health/drugs/15308- sleeping-pills.

Wallenbrock, Emma.“Melatonin: What Dose Is Right, and Why Too Much Is Bad.” Slate Magazine, The Slate Group, 13 June 2022, https://slate.com/technology/2022/06/melatoninoverdose-kids-drug-prescription.html.