It’s increasingly common to find melatonin — whether in capsule, jelly, or drop form — on bedside tables. The search for better sleep has clearly become an obsession.
In 2018, a study published in the Journal of the American Medical Association warned that twice as much melatonin was consumed in the United States as in the previous decade. Consumption of this hormonal supplement has increased further during the pandemic – some pharmacists recall selling up to 30 boxes a day.
Mild side effects of taking melatonin – which is already naturally produced by the body – have been regularly reported, such as drowsiness, dizziness, nausea and headaches…although these tend to subside soon after discontinuation of use. However, on social media, several users have recently reported strange dreams or nightmares after taking the hormone.
In her essay, An Ode to Darkness (2019), Norwegian journalist Sigri Sandberg calls melatonin the “hormone of darkness”. It is mainly secreted in the pineal gland, located in the center of the brain, when the body stops receiving signals from natural light. The gland knows its heyday between three and four in the morning.
Among its functions, melatonin prepares us for sleep by dilating blood vessels and reducing body temperature. The hormone is also a very powerful antioxidant, giving us the ability to revitalize ourselves while we sleep.
Melatonin secretion is impaired by an abundance of artificial light, which many students and workers frequently experience today as they stay up late on their computers or phones. A melatonin pill, drop, or gelatin can supplement a body that is affected by an overly enlightened life. When there is little difference between night and day, the natural secretion of the hormone is disturbed.
Experts call these supplements “exogenous melatonin,” to differentiate it from what we secrete — or should secrete — unaided.
“[Melatonin] is the hormone par excellence involved in the regulation of the sleep-wake cycle… its primary function is to induce sleep. Although its main synthesis resides in the pineal gland, it is also synthesized in other organs, such as the retina, bone marrow, skin, serotonin-producing cells of the gastrointestinal tract, cerebellum and the immune system. “says Dr. Alba García. -Aragón, medical specialist who works at the Madrid Sleep Research Institute.
“A circadian cycle lasts 24 hours. The onset of melatonin secretion coincides with the time of day when the concentration of adenosine – a substance produced by brain activity during wakefulness – is highest. When adenosine builds up, it causes a feeling of exhaustion. In this way, sleep is facilitated both by the accumulation of adenosine and by the gradual decrease in light which leads to the secretion of melatonin.
A meta-analysis of 19 clinical trials involving more than 1,600 adults and children with sleep disorders showed that melatonin reduced the time it took to fall asleep by seven minutes. It also increased time spent sleeping by eight minutes, while improving overall sleep quality and relieving short-term insomnia caused by jet lag.
There are as many types of melatonin on the market as there are insomniacs in the world. “Each type is prescribed based on the symptoms reported by the patient and based on the results of a previous sleep study. For this reason, it is difficult to say that one melatonin is better than another, because each treatment must be individualized,” says García-Aragón.Some formats of the hormone—although milder—are also readily available on grocery store shelves.
There are few studies on the use and abuse of melatonin, although the experts consulted by EL PAÍS describe a “lack of long-term quality data”. Dr Odile Romero, coordinator of the sleep unit at Vall d’Hebron Hospital in Barcelona, explains that she only had to withdraw melatonin because of headaches. In her clinical experience, she has not seen patients develop addictions or have nightmares.
However, some users – who spoke to EL PAÍS on condition of anonymity – reported bad dreams.
“I stopped taking melatonin the day I dreamed that I was an accomplice to murder. It was a very vivid dream,” one person recounts.
Claudia DC (pseudonym) explains that she bought a bottle of 60 2mg tablets on Amazon.
She also remembers “disturbing dreams… so many things happened to me that I woke up exhausted, as if I had just returned from a trip”. She went to see a doctor and was prescribed extended release melatonin. The dreams eventually ceased.
Anabel VC began taking melatonin supplements to relieve jet lag from her busy travel schedule. “I quit because of nightmares. I preferred to sleep badly. Months later, she gave it another try with smaller daily doses. “Now I have hyperrealistic dreams all night long, like it’s a movie, but they’re not nightmares. [Melatonin] meets my needs,” she says with a shrug.
Meanwhile, MM takes it every night, but she has a strategy: “I calculate the time and only take it when I know I have at least eight hours to sleep, otherwise I spend the next day having the hangover.
Can you become addicted to melatonin? The few available studies deny it… although many patients claim to be dependent. On Tiktok, the hashtag #melatoninaddict accumulates a million views – the problem is also widely discussed on Reddit. Neither platform can compete with a clinical trial, but active conversations on the subject cannot simply be dismissed.
Dr. Romero is not aware of any physical addiction to melatonin. “But I think it has a placebo effect and a lot of people fall asleep easier just by taking certain melatonin-containing products,” she explains.
García-Aragón also found no evidence of physical dependence during his consultations. “I haven’t seen any withdrawal symptoms when someone stops taking melatonin,” he told EL PAÍS. That said, he observed “some psychological dependence in patients undergoing prolonged melatonin treatment.”
Heavy consumers of melatonin are those who have been taking increasing doses of the hormone for more than five years. When asked if the practice is dangerous, Dr. Romero says she hasn’t seen “significant adverse effects”, but points out: “There is scientific debate and controversy about whether if high doses of melatonin could saturate the MT1 and MT2 receptors, which are responsible for binding with the hormone…it would reduce its effect. As a precaution – and in the absence of studies supporting the safety of long-term melatonin consumption – Dr. García-Aragón does not recommend maintaining treatment for more than three months.
About 85% of adults have at least one nightmare a year. Between 4% and 10% have one every week, probably related to stress. But little work has been done to see if nightmares, or ultra-vivid dreams, could be drug-related. Some experts have suggested the possibility, however, that the primary proven effect of melatonin supplements may have something to do with bad dreams: extending sleep duration.
We dream a lot during rapid eye movement (REM) sleep. This deep sleep usually begins about 90 minutes after falling asleep. This is the part of sleep where most dreams occur. So, it is possible that sleeping more could open the door to dreamland… and also to nightmares.