What is Melatonin?
Melatonin is a natural brain hormone that is secreted by a tiny gland deep within the brain called the pineal gland. We secrete melatonin as part of the normal sleep-wake cycle; it is believed to be triggered by darkness and is found in other animals that sleep at night besides humans. This gives it its other name, “the hormone of darkness”.
Melatonin can be found in a wide variety of foods but not in amounts that would trigger you to fall asleep. Instead, most people take it as a dietary supplement, available at supermarkets, health food stores, pharmacies, and online. When we humans take it or naturally secrete it, it helps trigger us to sleep. Interestingly, in animals who are nocturnal and spend their nighttime hours awake, melatonin has the opposite effect and is a trigger for these animals to stay awake during the night.
How is melatonin used?
Melatonin is used as a natural, non-addictive sleep aid throughout the modern world. It is metabolized in the liver very quickly so it has a fast onset of action. Because it is a natural substance, it is generally considered as safe.
Besides taking melatonin for insomnia, many people use melatonin to reset their circadian rhythm while travelling. It helps you get better adjusted to the time zone changes you experience when you travel to other parts of the world. Tiny amounts of melatonin (about 0.3 mg) when taken orally can shift your sleep-wake cycle ahead a few hours when compared to your normal sleep-wake cycle so you can get to sleep earlier, sleep a normal amount of sleep hours, and feel refreshed the next morning without the hangover effect of many sleeping pills.
Melatonin receives signals of impending darkness by the part of the brain known as the suprachiasmic nucleus, which in turn receives signals from the eyes themselves. The circadian rhythm is not a perfect 24 hour period of time so that blind people, who don’t receive the brain signal to produce melatonin when they are supposed to operate on a shorter circadian rhythm and cannot naturally go to sleep at the same time every night. They tend to have more irregular sleep patterns based on other circadian signals besides melatonin.
Natural melatonin, as mentioned, is secreted by the pineal gland which is deep inside the skull but is not technically a part of the brain as a whole. In a normal person, melatonin levels in the body begin to elevate by early evening, reaching a peak about the time you go to bed, staying high throughout the night, only to drop to daytime levels in the early morning, signaling the need to wake up. Unfortunately, many people keep their sleep-wake cycle patterns based on an alarm clock or need to sleep during the day because of night shift work. Trying to sleep this way is counterintuitive to the body’s natural melatonin secretion, making daytime sleep less satisfying and successful than nighttime sleep.
Melatonin and the Seasons
Melatonin production varies with the time of year or seasons, especially in the extreme northern and southern parts of the world. When the days become shorter, your retinas experience the relative loss of light that occurs earlier in a winter day (in the Northern Hemisphere) and melatonin production occurs earlier in the evening than it does in the summertime. It is believed that this shift in melatonin production during the darkest days of the year contributes to the onset of SAD, also called “seasonal affective disorder”.
The amount of melatonin secreted by the pineal gland lessens as one ages so that many older adults quit making melatonin at all. This is believed to be why older adults sleep more poorly than younger adults.
Melatonin Use in Medicine
Melatonin can be used artificially in humans for several sleep-related conditions. As mentioned, it can be used as a treatment for insomnia or for jet lag in travelers. It may also have a role in managing the symptoms of seasonal affective disorder, difficulty sleeping in those who work the night shift at work and in helping postoperative patients recover from surgery without sleep disturbance and confusion. People who experience frequent bouts of cluster headaches can sometimes find relief from taking melatonin.
If you have been suffering for a long time with sleep-related disorders such as insomnia, the taking of this natural hormone can help the condition without having to take potentially-addictive prescription sleep aids. Melatonin can be found over the counter so that anyone with a sleep problem can try it before going to the doctor for further management if the melatonin doesn’t impact sleep in the way it is supposed to. If you have health problems or plan to take melatonin for a long period of time, check with your doctor before going on a regimen of daily melatonin intake.
Side Effects of Melatonin
While melatonin is considered to be extremely safe, it is possible to have a melatonin overdose. You should check with your doctor before taking the supplement if you are pregnant or nursing as melatonin is found to be present in breast milk. Side effects of taking melatonin include the following:
- Tiredness during the daytime hours
- Vivid dreaming
- A lower body temperature
- Blood pressure changes
- Feeling tired in the morning, especially upon arising
Because melatonin can induce drowsiness, you shouldn’t be driving or operating heavy machinery while taking melatonin until you find out what taking melatonin does to you. Melatonin may also be blocking symptoms of insomnia due to a medical condition that really needs a doctor’s attention rather than a melatonin supplement.
Be sure to take synthetic melatonin and not the melatonin extracted from cows. There is a risk of transmission of things like mad cow disease and other bovine diseases if you take the extracted melatonin.