The melatonin controversy: is it advisable to take it?

Melatonin has invaded our bedside tables. The hormone of darkness, as Norwegian journalist Sigri Sandberg has named it in her essay An Ode to Darkness (Captain Swing, 2022), is secreted in the pineal gland when the brain stops receiving the signal of natural light. It is at its best between three and four o’clock in the morning and its production decreases with age. Some said that sleep was the new sex. A good night’s sleep has become an object of desire. Perhaps that is why melatonin in capsules, gummies or drops has become part of our lives.

Its functions include preparing us for sleep by dilating blood vessels and lowering body temperature. It is also a very powerful antioxidant. Melatonin secretion is altered by an abundance of artificial light. What we do when we take a melatonin pill or a melatonin gummy is to supplement a function of our body that is disturbed by an excessively enlightened life, where there is little difference between day and night, a circumstance that disturbs the secretion of this hormone, which is governed by circadian rhythms.

“Melatonin, as well as regulating circadian rhythms, acts as a powerful antioxidant in the body, as it has the ability to fight free radicals and reduce oxidative stress. This helps protect cells and tissues from damage caused by oxidation and may be related to longevity and health,” explains Dr Mariel Silva, an expert in Integrative Medicine and Anti-Ageing at SHA Wellness Clinic, adding: “melatonin has been shown to be involved in modulating the immune system and is being studied for its beneficial effect on autoimmune diseases”.

Melatonin has been available in Spain for years; in 2007. The first sleep drug with melatonin as the active ingredient was authorised in doses of 2 milligrams (mg) per tablet. In addition, the marketing of food supplements containing this hormone was authorised provided that the doses did not exceed 1.9 mg. Since then, consumption has skyrocketed, with an exuberant peak during the pandemic, when pharmacists recall selling as many as 30 boxes in one day.. A study published in JAMA in 2018 claims that more than twice as much melatonin was being consumed in the US than in the previous decade.

Those pills we take are “exogenous melatonin”. This is what experts call it to differentiate it from the fact that we secrete it or should secrete it unaided. There are as many types of melatonin on the market as there are insomniacs in the world. This diversity explains the varied experiences of regular consumers of this supplement. Those on the market are usually differentiated by dosage and mode of release.

Dr Silva explains that there is great variability in how exogenous melatonin can affect those who take it. “Firstly, natural melatonin production varies from person to person and decreases with age. This may influence the amount of melatonin available to regulate sleep and other biological processes. On the other hand, an individual’s response to melatonin may be influenced by genetic factors. Lifestyle factors such as exposure to artificial light at night, sleep schedule, diet and stress can also impact how melatonin interacts with a person’s circadian system.

Dr Vicente Mera, head of the SHA Wellness Clinic’s Internal Medicine and Well-ageing Unit, points out that the effects of melatonin on sleep show great interpersonal variability. “Not only in terms of the ability to induce and maintain sleep, but also in terms of the undesirable effects on dreaming.  The presence of vivid dreams rather than real nightmares is one of the undesirable effects that occur in people taking very high doses, above 5 mg”.

So what is the best way to consume melatonin? Dr Silva points out that this can vary according to individual needs and purpose. “To improve sleep quality, especially in cases of insomnia, low doses, usually around 0.5 mg to 1 mg, taken approximately 30 minutes before bedtime, are recommended. In young adults, it has been observed that doses of 5 mg can significantly increase sleep propensity and REM sleep duration, suggesting improvements in sleep quality. For older people with insomnia, administration of melatonin in the form of sustained-release tablets (1 mg or 2 mg per day) for three weeks has been shown to improve both the quality and duration of sleep.

“When melatonin is used as an antioxidant, doses can vary between 3mg and 10 mg. The timing of intake also changes, but it is often taken before bedtime to take advantage of its antioxidant capacity during the night, when the body is most exposed to oxidative stress,” adds Dr Silva, who recommends always consulting a health professional before starting melatonin supplementation, especially if there are pre-existing conditions or if you are taking other medications.

Melatonin never fails to provide pleasant surprises. Recent scientific advances indicate that there are indications of its potential impact on cardiovascular health. Ongoing research suggests that it may have beneficial effects on blood pressure regulation and endothelial function, which could make its use relevant for the prevention of cardiovascular disease.