Melatonin Is a Hormone, Not a Sleeping Pill: What to Do Instead

Two years ago I was living across two time zones and taking melatonin almost every evening. Three milligrams, the standard pharmacy tablet. I fell asleep faster, that much is true. Then I would reliably wake at four in the morning with my head full of cotton wool and not be able to think straight until lunch. I blamed the flights. Until I read that three milligrams is roughly ten times more than my body produces on its own in a whole night.

Since then melatonin lives in my travel kit for one scenario only: the day of a flight across several time zones. Not as a sleeping pill. Here is why.

What melatonin is and why people are worried

Melatonin is a hormone. Not a vitamin, not a "sleep supplement", not a herbal extract. It is made by the pineal gland in the brain, and the gland responds to a single signal: darkness. During the day the concentration of melatonin in the blood is close to zero. As darkness falls it rises roughly tenfold, peaks between two and four in the morning, and drops towards dawn.

The hormone's job is not to switch you off. Its job is to tell every cell in the body that it is now night. The heart, the liver, the gut, the immune cells. It is a time signal, not a sleep signal. That distinction is fundamental, and everything else rests on it.

Where the worry came from. In November 2025 an observational study was presented at the American Heart Association's scientific sessions: people who had taken melatonin for a year or longer were recorded as developing heart failure noticeably more often than those who had not. The sample was more than 130,000 people. The headlines spread within a day, and on sleep forums the word "melatonin" started to sound like the word "risk".

Honesty is needed in both directions here. This was an observational study, not an experiment. It shows an association, not a cause. People who take melatonin for years are more likely to have chronic insomnia, and insomnia itself is linked to heart disease. A design like this cannot separate the two. But it cannot be waved away either: long-term data on daily melatonin use in healthy adults barely exists. Efficacy trials run for weeks, occasionally months. Nobody has tested what happens after five years of three milligrams every night.

So the honest answer to "is it dangerous to take melatonin for years" is: unknown. And that alone is reason enough not to do it without a need.

How melatonin works, and why the tablet doesn't send you to sleep

Let's go through the mechanism, because it explains most people's disappointment.

Your own melatonin starts when bright light stops reaching the retina. Light-sensitive cells containing the pigment melanopsin, the same cells that set the cortisol curve, tell the central clock in the hypothalamus that it has gone dark. The clock instructs the pineal gland. The hormone enters the blood and carries the "night" message to the organs.

Notice what is missing from that chain. There is no direct sleep switch. Melatonin does not act on the same receptors as hypnotic drugs and does not suppress the nervous system. It shifts the phase of the internal clock and lowers the clock's "stay awake" signal in the evening hours. That is all.

Hence the numbers that rarely appear on the packaging. A large 2013 meta-analysis pooling 19 trials and more than 1,600 participants found that melatonin shortens the time to fall asleep by an average of seven minutes and lengthens total sleep by about eight minutes. Seven and eight. Statistically significant and clinically almost invisible. The American Academy of Sleep Medicine, in its clinical guideline on chronic insomnia, does not recommend melatonin, not because it is harmful but because the evidence of benefit is insufficient.

Now the dose. The physiological night-time concentration of melatonin in the blood is reproduced by a dose of about 0.3 to 0.5 mg. The standard pharmacy tablet is 3 mg; gummies in the United States come in 5 and 10 mg. That is ten to twenty times more than the signal requires. The excess does not strengthen the effect. It prolongs it: the hormone level stays high in the morning, when the body should be receiving the "day" command. Hence my cotton-wool head at four in the morning and the morning grogginess so many people describe.

One more point that is rarely mentioned. In most countries melatonin is sold as a food supplement rather than a medicine, and nobody is obliged to check the tablet's content with any rigour. A Canadian study from 2017 analysed 31 products: the actual content deviated from the label by anywhere between minus 83 and plus 478 per cent. A 2023 study of gummies in JAMA found a similar picture: in most samples the dose did not match the label, and in one it was almost three and a half times higher. A person believes they are taking three milligrams. They may be taking one. Or twelve.

What melatonin does well

I am not about to declare it useless. Melatonin has a niche in which it works precisely and honestly: phase shifting.

Jet lag. If you have flown across five time zones, your internal clock is showing the wrong time, and a small dose of melatonin at the right moment helps to reset it. This is its direct purpose: not to sedate you, but to tell the clock when night falls in the new place.

Delayed sleep phase syndrome. People who physically cannot fall asleep before three in the morning or wake before eleven. Here melatonin taken several hours before the desired bedtime gradually moves the phase earlier. It works, it is documented, and it is used under medical supervision.

Shift work. Night shifts and daytime sleep: again a story about the clock, not about sleep.

Older age. After 55 to 60 the body's own melatonin output drops noticeably, and in Europe a prescription-only prolonged-release melatonin of 2 mg is licensed for this group. Note the details: two milligrams, on prescription, for a specific age group.

In all of these cases the common thread is the same: melatonin is used as a rhythm-correction tool for a limited period. Not as a nightly tablet to "knock yourself out".

Who melatonin is not for

No softening here.

Those with insomnia rather than a rhythm problem. If you go to bed at eleven, lie there until two and wake at five with a pounding heart, that is not a clock problem. It is anxiety, sleep apnoea, pain, hormonal change or something else that has a diagnosis. Melatonin will not support that; it will simply postpone the visit to a specialist.

Those taking it daily for more than three months. Not because harm has been proven, but because safety has not, and because daily intake shifts not only sleep but everything tied to the daily rhythm: body temperature, blood pressure, insulin sensitivity.

Children and teenagers. Calls to US poison centres about melatonin in children multiplied over a decade, largely because of sweet gummies. A child's own melatonin output is normally high; adding a hormone without a doctor's instruction is a poor idea.

During pregnancy, with autoimmune conditions, and alongside anticoagulants, antidepressants, blood-pressure medication or immunosuppressants: only via a doctor. Melatonin interacts with many of them.

And anyone driving in the morning after a 5 mg tablet the night before. Residual drowsiness is real.

What to do instead: a four-week protocol

The logic is simple. If melatonin is the "night" signal, the main way to get enough of it is to give the body the conditions under which it produces the signal itself. Your own melatonin is precise in dose, precise in timing, and switches off at dawn. No tablet can do that.

First, light in the morning. Twenty to thirty minutes of bright light in the first hour after waking. Paradoxically, the best thing you can do for evening melatonin is the morning. Bright morning light anchors the clock's phase, and the evening rise of the hormone arrives 14 to 16 hours later, on schedule. Without morning light the clock drifts and the evening signal comes late.

Second, darkness in the evening, and the numbers here are harsher than they seem. Ordinary room lighting of 100 to 300 lux suppresses melatonin secretion by roughly half. Not the blue glow of a phone, an ordinary ceiling light. Two hours before bed: overhead lights off, warm sources below eye level only. Screens on minimum brightness and night mode, or better, put away. If evening work at a monitor is unavoidable, glasses that filter the blue part of the spectrum take some of the load off the melanopsin cells. They do not replace darkness, but they soften its absence.

Third, temperature. Falling asleep is physiologically linked to a drop in core body temperature of about one degree. A cool bedroom, 17 to 19 degrees, speeds this up. And a counter-intuitive trick: a warm shower or a warm-up session an hour to ninety minutes before bed. The body heats up, then actively sheds heat through the skin, and core temperature falls faster. I wrote about this mechanism, and about how TCM understands evening warmth, in my piece on sleep quality.

Fourth, timing. The same wake-up time seven days a week. Not bedtime, wake-up time. The clock synchronises on the morning, and "sleeping in until noon on Saturday" pushes Sunday evening's melatonin peak an hour or two later. Hence the heavy Monday.

Fifth, caffeine before 2 pm. Its half-life is five to six hours, and a cup at four in the afternoon leaves a quarter of the dose at midnight. Caffeine directly suppresses the evening rise of melatonin.

Sixth, an evening ritual with TCM logic. In Chinese medicine the night begins not when you lie down but an hour or two earlier: warm drinks instead of cold, warm feet, no intense exercise after eight in the evening. Mechanically this is the same thermoregulation story and a lowering of sympathetic tone. I have two standing tools here: Lyusi tea instead of evening coffee, and warming the feet, because the feet with their dense network of vessels are the fastest "radiator" for shedding core heat.

Seventh, a course of support, if you need one at all. Among TCM adaptogens, Lingzhi is the usual evening choice: the mushroom does not sedate, but with regular use it supports the nervous system's normal response to stress, which means it works on the cause of late nights rather than the symptom. I have a separate article on the mushroom itself; the evaluation horizon is 30 days, anything shorter is pointless. And if you are serious about the bedroom rather than the tablets, it makes more sense to invest in the sleep environment than in a sleeping pill: temperature, darkness, bedding materials with far-infrared warmth and an anion layer. That works every night, with no residual drowsiness and no question of "what happens after five years".

What to do with melatonin if it is already a habit. Don't stop abruptly. There is no withdrawal syndrome, but the sudden disappearance of a familiar ritual disrupts sleep on its own. Reduce the dose to 0.5 to 1 mg, move the intake to two or three hours before bed instead of "at the pillow", and introduce morning light and evening darkness in parallel. After two or three weeks, try an evening without the tablet. If sleep holds, the goal is reached. If not, that is a reason to talk to a sleep specialist, not to go back to 5 mg.

Conclusion

Melatonin is a hormone that tells the body the time. It does not send you to sleep, and the data confirm it: seven minutes gained in sleep onset at a typical dose ten times the physiological one. It has a clear niche: flights, phase shifts, shift work, older age under medical supervision. Outside that niche, nightly use for years is an experiment whose results nobody knows, and the 2025 study was the first loud reminder of that.

The good news is that the main producer of melatonin is you. Morning light, evening darkness, a cool room, a fixed wake-up time, caffeine before two and a warm evening ritual give the body everything it needs to produce the "night" signal in the right dose at the right time. My benchmark is two weeks to the first tangible shift and a month to the state where the tablet in the travel kit is needed only at the airport.