What Is Melatonin? A HealthCentral Explainer

Falling asleep can be difficult for people suffering from anxiety, taking certain medications--such as beta-blockers--or experiencing other health issues. While there’s medication to treat sleep problems, melatonin might be a better option for some people.

What is melatonin?

Melatonin is a hormone produced in the pineal gland of the brain and in the retinas of our eyes. It is triggered by darkness, with production beginning around 9 p.m. and peaking between 2 and 4 a.m. Then it begins to recede. Melatonin is involved in regulating the sleep and wake cycles and is sometimes used in a synthetic form to treat sleep problems. However, melatonin is not a sleep initiator; it simply tells your brain when it is time to sleep, but does not increase sleep drive. This is why melatonin is particularly effective at treating circadian rhythm disorders – when people sleep the right amount of minutes, but not at the correct time – but may not be as effective in treating insomnia, according to Psychology Today.

The correct dosage for melatonin is between 0.3 and 1.0 mg, and is sold as a dietary supplement in the U.S. With supplements, there are no Food and Drug Administration (FDA) standards or regulations, as there are with prescription medications. In addition, melatonin should be used only for less than three months.

Has it been proven to help people sleep?

People who are given beta-blockers for the treatment of cardiovascular conditions, hypertension and anxiety can experience sleep problems from the medication. One recent study looked at how the use of melatonin supplements could improve sleep in patients taking beta-blockers for hypertension, and found that sleep time increased and perceived quality of sleep improved.

Sixteen people participated in the three-week study, and made two visits to the lab. Each visit lasted four days, as the patients were given either melatonin or a placebo, and then observed while they slept. Researchers found that people who took the melatonin increased sleep time by 37 minutes in comparison to those who took a placebo. They also determined that participants had an 8 percent boost in how soundly they slept.

Another study looked at melatonin to understand how receptors in the brain promote deep, restorative sleep, with the goal of developing a drug to activate this receptor. The drug, called UCM765, increased the phases of deep sleep in rats and mice, and affects the part of the brain responsible for deep sleep.

Researchers say it could be a better treatment for insomnia than traditional medication, because it increases the duration of sleep without changing REM sleep.

Melatonin has also been shown to re-establish the biological clock in blind people. Because melatonin is activated by darkness around 9 p.m., blind people cannot make use of the visual information to start production. Scientists found that having blind people take a melatonin supplement every 24 hours syncs up their sleep-wake cycle on a 24-hour period.

What else might melatonin treat?

Melatonin has also been shown to have potential to improve Parkinson’s disease, cluster headaches and sleep problems in kids with autism.  There is likewise some evidence it helps people quit smoking, reduces anxiety before surgery, eases jet lag and decreases sunburn when applied in a cream form before going out in the sun.

One recent study found that voluntary exercise and daily intake of melatonin was able to produce a synergistic effect against brain deterioration in mice with three different mutations of Alzheimer’s disease (3xTg-AD). The mice were divided into a control group and three other groups that either received exercise alone, melatonin alone, or a combination of both. After six months, the mice that had the combination treatment showed significant improvement.

Researchers note, however, that this treatment cannot be easily transferred to humans because the disease develops over several years in people and by the time memory loss surfaces, the brain has already deteriorated.

Another study in rats looked at how melatonin helps in controlling weight, and found that not only did it control weight, but it did so without reducing intake of food. It also improved blood lipid profiles. Researchers studied young, diabetic obese rats, and found that the melatonin was helpful to young rats that had not yet developed metabolic disease or heart disease. Researchers concluded that melatonin could help prevent heart disease associated with obesity.

A third study looked at women undergoing IVF treatment, who had poor quality eggs. They were split into two groups - one group of 56 women received 3mg of melatonin before their next IVF cycle, and 59 women had a standard IVF cycle without melatonin. The team found that melatonin significantly improved the quality of eggs. Fifty percent of the eggs from the women who had taken melatonin could be successfully fertilized, while only 22.8 percent could be fertilized from the control group.

Are there any unsafe side effects?

Melatonin should be safe for most adults, but can cause some side effects, such as headaches, short-term feelings of depression, daytime sleepiness, dizziness, stomach cramps and irritability. Certain people should probably not take melatonin, such as pregnant or breast-feeding women, and those with high blood pressure, diabetes, depression and seizure disorders.

Some combinations of drugs could also have potentially harmful side effects. Sedatives should not be used with melatonin and women taking birth control pills should be careful, as taking both could cause too much melatonin in the body.

Bottom line: Since the FDA does not regulate melatonin supplements as they do prescription medications, they should be taken with a level of caution. Talk to your doctor to see if melatonin could work for your health needs.


n.p. (2011, December 24). “Melatonin.” Medline Plus. Retrieved from http://www.nlm.nih.gov/medlineplus/druginfo/natural/940.html

n.p. “Mental Health Disorders.” Curiosity.com. Retrieved on http://curiosity.discovery.com/question/how-does-melatonin-work

Breus, Ph.D., Michael J. (2011, February 22). “Melatonin: Not a Magic Bullet for Sleep_.” Psychology Today_. Retrieved from [http://www.psychologytoday.com/blog/sleep-newzzz/201102/melatonin-not-magic-bullet-sleep](http://www.psychologytoday.com/blog/sleep-newzzz/201102/melatonin-not-magic-bullet-sleep/)

Christian Nordqvist. (2011, August 2). "What Is Melatonin?." Medical News Today. Retrieved from

n.p. (2012, September 28). "Melatonin Helps Hypertension Patients Sleep." Medical News Today. Retrieved from http://www.medicalnewstoday.com/articles/250864.php

McGill University Health Centre. (2011, December 15). "'Sleep Hormone' Discovery Leads To Novel Melatonin Drug With Potential To Treat Insomnia." Medical News Today. Retrieved from http://www.medicalnewstoday.com/releases/239179.php

University of Granada. (2009, November 6). "The Consumption Of Melatonin, A Natural Hormone Secreted By The Own Human Body, Regulates Sleep Better Than Somniferous." Medical News Today. Retrieved from http://www.medicalnewstoday.com/releases/170052.php

n.p. (2012, September 28). "Positive Effects In Alzheimer's To Melatonin And Exercise In Mouse Model." Medical News Today. Retrieved from http://www.medicalnewstoday.com/releases/250741.php.

University of Granada. (2011, April 29). "Melatonin Might Help In Controlling Weight Gain And Preventing Heart Diseases Associated To Obesity." Medical News Today. Retrieved from http://www.medicalnewstoday.com/releases/223671.php

International Federation of Fertility Societies. (2010, September 15). "Study Shows Melatonin Almost Doubles IVF Success Rate In Women With Poor Egg Quality." Medical News Today. Retrieved from http://www.medicalnewstoday.com/releases/201071.php