I have been a physician for over 20 years, 12 of which have been dedicated exclusively to the practice of sleep medicine. Over the years, I have seen a huge increase in the use of melatonin by my patients and their families. Although melatonin has helped many of my patients, I have some concerns that are worth sharing.
First, I’m not sure that most of my patients who were taking melatonin before my clinical evaluation knew exactly what melatonin was. Melatonin is a hormone produced by a gland in the brain called the pineal gland. The main function of melatonin is the regulation of sleep.
Melatonin levels rise in response to darkness, signaling to the brain that night has arrived and it’s time to sleep. When there is bright light, like in the morning, the production of melatonin stops and the brain knows it is daytime.
The day-night regulating properties of melatonin and light make them the two key factors in setting up the internal sleep-wake clock, or what is known as the “circadian cycle”.
A circadian disorder occurs when there is a mismatch between the internal clock and the socially accepted time for falling asleep or waking up, as seen when someone travels across time zones and suffers from jet lag . But jet lag can sometimes occur in the absence of travel. For example, when you stay in a brightly lit environment until late at night, you trick your brain into thinking it’s still daytime. In this case, melatonin production does not occur and you only feel sleepy late at night or sometimes early in the morning.
I have seen many teenagers come to my clinic because they can’t sleep until 2 or 3 in the morning, but they watch videos on their electronic devices late into the night.
I generally recommend that my patients turn off the lights at a reasonable time and expect drowsiness to begin to occur within an hour. But it takes time for the natural clock to adjust to a new schedule, and often my patients prefer to use a melatonin supplement to speed up circadian time adjustment.
With the increase in the use of electronic devices, sleep disturbances have become quite common and melatonin use increased. Due to its sleep-promoting properties, melatonin is also an incredibly appealing option for people with insomnia or sleep disorders.
In some countries, such as the United States, melatonin can be purchased without a prescription. This situation worries me because a lack of regulation can mean an increased risk of taking a different dose or ingredients than reported. In fact, a study on melatonin supplements found that the hormone content ranged from -83% to +478% of tagged content. The researchers also discovered other substances that had not been reported in the preparation, including serotonin and valerian.
In the EU, UK and Australia, melatonin is obtained only by prescription for the short-term treatment of insomnia. This approach makes it possible to better regulate, understand and explain the risks, benefits and alternatives to the use of melatonin.
Even though melatonin is a natural hormone, it is not without side effects, the most common being headaches and dizziness. It can also interact with other medicines, such as blood thinners (medicines that help prevent blood clots from forming).
The best proof of security for melatonin use is for short term use only (one to three months) and low dose (0.5-1mg). The long-term effects of melatonin remain unknown.
Did I use melatonin or did I recommend it to my patients? Absolutely. But only when I know exactly why I recommend it. Insomnia can be a symptom of a sleep disorder, such as restless legs syndrome or obstructive sleep apnea, or a symptom of another condition, such as depression, asthma, or pain.
When a sleep specialist identifies the correct diagnosis, treatment options can be explored. When I need to prescribe melatonin, I generally recommend starting with the lowest possible dose (0.5 mg) one to two hours before the current bedtime, and I recommend that the patient turn off their lights or attenuates them before taking melatonin. I also recommend avoiding other contributing factors to poor sleep, such as caffeinated products after 3 p.m., strenuous exercise in the evening, or using electronic devices before bed.
Correction: An earlier version of this article stated that melatonin supplements are only available by prescription in Canada. This is an error.