As medication goes, melatonin is a fairly recent discovery. It was only in 1958 that a dermatology professor at Yale University isolated the hormone from the pineal gland of cows, and the discovery that it regulates the circadian rhythm, or day-night cycle, in humans was made in the 1970s. It began to be used as a sleep-aid only in 1995 and was approved for medical use in most countries just about 15 years ago. Even then, it was typically seen as something that would help frequent fliers, especially those who took transatlantic flights, get over jet lag.
Melatonin’s use as a sleep-aid by people who are not trying to adapt to different time zones or work in jobs that involve regular shift changes, is fairly recent—in India, it started gaining in popularity only three-four years ago. But before you decide to pop that melatonin pill—available over-the-counter in India and in some other countries like the US but not, for instance, in the European Union—you need to understand how melatonin makes you sleepy.
Unlike prescription drugs like benzodiazepines (diazepam and alprazolam are two specific drugs in this family), which work by raising the level of certain neurotransmitters that literally make your nerves calmer, melatonin essentially signals the brain that it is time to go to sleep. Released by the pineal gland in the human brain (and also produced in minor levels in the retina, bone marrow cells, platelets, skin and lymphocytes), melatonin is a hormone whose concentration in the body rises and falls with the day-and-night cycle. Darkness causes the body to produce more melatonin, a signal for the body to prepare for sleep by promoting sleepiness; with daylight, the production of melatonin goes down, telling the brain and the body to be awake and alert. Two receptor proteins in the brain bind to the hormone and through a complex signalling mechanism, produce a feeling of sleepiness in humans.
Ever wondered why newborn children have difficulty remaining asleep at night? Research has shown that their melatonin levels become regular only about three months from birth, which is when most babies begin to sleep through the night. Another interesting observation in melatonin levels among different age groups explains the profound mystery of why teenagers have weird sleep cycles: As children become teenagers, the nightly schedule of melatonin release is delayed, leading to later sleeping and waking times (according to a widely quoted 2009 paper, Adolescent Changes In The Homeostatic And Circadian Regulation Of Sleep, published in the academic journal Developmental Neuroscience).
When we talk about blue light emitted by smartphone and laptop screens interfering with sleep, it is, once again, linked to melatonin production: Blue light suppresses melatonin biosynthesis, leading to a drop in the level of the hormone in the body and delayed sleep.
Given the scientific evidence of melatonin’s role in maintaining a healthy sleep cycle, and the fact that it is seen as a “natural” alternative to addictive prescription medication for insomnia, should one simply pop a melatonin pill when having trouble falling asleep at night—especially during the pandemic, when doctors are reporting higher stress levels and anxiety issues leading to sleep deprivation?
“From my observation of my patients, I can say that the pandemic has had a significant impact on sleep. Primarily, this is linked to heightened anxiety as well as a lack of routine among those who continue to work from home. Their days are not organized and schedules have been disrupted; for many people, since they don’t have to wake up early in the morning in order to leave the house by a certain time, sleep times have been pushed back,” says Sabina Rao, consultant psychiatrist at Columbia Asia Hospital, Sarjapur Road, Bengaluru. “I do prescribe melatonin in such cases. I start patients on melatonin when they have trouble initiating sleep,” adds Dr Rao. “It is not very useful in situations where a patient has trouble maintaining sleep.”
“Self-prescribing melatonin tablets is permissible if someone is using it to treat jet lag and is taking one tablet per day for around a week or so, but for longer-term use, it’s best to seek a doctor’s advice,” says Sibashish Dey, head of clinical affairs at ResMed India a chain of clinics which specialises in the treatment of sleep apnea and respiratory medicine. “If you use melatonin under normal circumstances to set your sleep cycle, it should be done under medical supervision.”
One of the main reasons for this is that melatonin may interact with other drugs, for instance any medication you might be taking to regulate diabetes, and this may cause adverse side effects, says Dr Dey. Other side-effects include dizziness, nausea and headaches, though these are not very common.
According to Dr Rao, if you are buying melatonin over the counter, make sure you start with the lowest dosage, which is 3mg. Take it 2-3 hours before you go to bed. “For instance, if you are a gamer who stays up till very late at night and you want to change this habit and sleep early, don’t wait till you are ready to hit the bed to take melatonin because it doesn’t have an instant effect. It needs to build up in your system,” says Dr Rao. “Using melatonin for around a week to create a change in your sleep routine is fine but beyond that, it’s best not to self-medicate.”