Can You Take Melatonin Every Day? What Is Known About the Risks

You should not take melatonin every day without discussing it with a doctor. A short course may sometimes be appropriate, but long-term melatonin use is a reason to look into why sleep does not come naturally, review your medications, and establish a clear timeframe for reassessing the plan.

Melatonin is a hormone the body produces in the evening in response to darkness. In a tablet, it remains the same substance, but “natural” does not mean risk-free. The dose, timing, age, other medications, and cause of insomnia can change the picture far more than the word natural on the package.

Why people are talking about heart failure and melatonin

The discussion was prompted by a publication in ScienceDaily on August 29, 2026 (Ekenedilichukwu Nnadi and colleagues, American Heart Association Scientific Sessions) about an observational study in which long-term melatonin use was associated with a higher incidence of heart failure. The researchers analyzed data from 130,828 adults with chronic insomnia. Among people with documented long-term melatonin use — 12 months or more — heart failure was diagnosed in 4.6% over the following five years, compared with 2.7% in a comparable group without documented melatonin use. This corresponds to an approximately 90% higher relative risk. Such news can frighten someone who has kept a bottle on the bedside table for years. There is no need to panic and throw the medication away that same minute. But dismissing the signal is not the answer either.

An observational study examines existing medical histories and looks for associations between them. It does not randomly give people melatonin or a placebo, so it cannot answer the question: “Did melatonin cause the disease?”

People who take a sleep aid for a long time often have more severe insomnia. They may also be more likely to have sleep apnea, anxiety, depression, chronic pain, excess weight, night-shift work, alcohol use, and pre-existing cardiovascular problems. Each of these factors can affect both sleep and heart health. Another possibility is that the first symptoms of heart failure, such as nighttime shortness of breath or frequent awakenings, may themselves prompt a person to buy melatonin.

A concerning association is a good reason to review the habit, but a poor reason to declare the supplement a proven cause of disease.

To speak more confidently about causation, researchers need repeated studies, careful accounting for coexisting illnesses, and, where possible, randomized trials. For now, the honest position is simple: long-term use raises questions that cannot be answered with the phrase “it is only a hormone.”

When melatonin is used every day — and for how long

There are situations in which a doctor may genuinely recommend regular melatonin use: jet lag, shift work, certain circadian rhythm disorders, and sometimes for older adults with a specific insomnia profile. These are different tasks. With jet lag, several days and precise timing matter; with a shifted sleep schedule, light exposure and a consistent schedule are important; with chronic insomnia, the focus is on identifying the habits and conditions that sustain it.

In its 2017 clinical guidelines, the American Academy of Sleep Medicine did not recommend melatonin for treating insomnia involving difficulty falling asleep or staying asleep in adults; the recommendation was weak because of limited evidence. This does not mean the supplement is “banned” or that it helps no one. It means that for chronic insomnia, it is not considered a reliable first-line solution.

If you take melatonin for ten evenings before a flight, that is one situation. If you have been afraid to go to sleep without it for two years, that is entirely different. The second scenario deserves an in-person consultation, even if the tablet really does help you fall asleep faster.

In a review of studies by Jonathan Emens and Helen Burgess, 2015, Sleep Medicine Clinics on circadian physiology, the authors showed that light and melatonin work as signals capable of shifting the internal biological clock, with the effect depending primarily on the timing of exposure. Light is the most powerful external synchronizer of the circadian system: morning light generally shifts the biological clock earlier, while evening light shifts it later. Melatonin acts in virtually the opposite temporal direction: taking it in the afternoon and early evening may shift the circadian phase earlier, while taking it in the morning may shift it later. Therefore, the authors emphasize that when melatonin is used to correct circadian rhythms, not only the dose but also the exact timing of administration relative to a person's internal biological clock matters.

Melatonin: side effects, interactions, and the quality of the bottle

The most common complaints are quite ordinary: morning grogginess, vivid dreams, headache, dizziness, nausea, and irritability. Sometimes a person attributes sluggishness to bad weather or burnout, when simply shifting the timing, reducing the dose, or stopping the product is enough for mental clarity to return.

Caution is needed when taking anticoagulants and antiplatelet drugs, blood-pressure medications, diabetes medications, sedatives, and alcohol. Pregnancy, breastfeeding, epilepsy, autoimmune diseases, and significant liver or kidney disease are reasons not to select melatonin on your own. Children should also not be given it “just in case”: a pediatrician should first determine what is happening with their sleep.

The composition itself is another concern. In a study by Lauren Erland and Kamila Saxena, published in the Journal of Clinical Sleep Medicine in 2017, the melatonin content of the 31 supplements analyzed differed substantially from the amount stated on the label: the authors found deviations ranging from −83% to +478%. Serotonin was detected in some samples. Therefore, the habit of increasing the dose on your own is especially questionable: you may simply not know how much of the substance you received.

People who monitor their blood pressure or are already being treated for hypertension should approach home experiments with supplements especially cautiously. A similar logic is discussed in the article about peppermint oil and blood pressure: even a plant-based product should be kept separate from prescribed treatment and assessed through clear observations.

When insomnia stops being an episode

After a difficult week, almost anyone may spend several nights tossing and turning, wake up at four in the morning, or fall asleep with a TV series playing. This is unpleasant, but it is not necessarily a sleep disorder. Chronic insomnia is generally discussed when difficulty falling asleep, nighttime awakenings, or waking too early occur at least three times a week and continue for three months, while during the day you pay the price through fatigue, mistakes, or a low mood.

These are signs that make it sensible to schedule an appointment with a doctor or sleep specialist rather than extending the course at random:

• you take melatonin almost every evening for more than three months;

• sleep seems impossible without the tablet, even though you have already had to increase the dose;

• your partner hears loud snoring, breathing pauses, gasping, or choking during sleep;

• you wake up with palpitations, shortness of breath, chest pain, or marked swelling in your legs;

• you become sleepy while driving, in meetings, or on public transport;

• you watch a series in the evening and cannot remember the next morning how the previous episode ended;

• persistent anxiety, low mood, or thoughts that you do not want to live have appeared alongside the insomnia.

Shortness of breath at rest, chest pain or pressure, fainting, or sudden severe weakness require urgent medical attention. Do not wait to see whether the next capsule helps you sleep.

What to discuss with a doctor if you want to sleep without a tablet

Prepare a brief sleep diary for at least 14 days. Record when you went to bed and got up, the approximate time you fell asleep, awakenings, caffeine after lunch, alcohol, daytime naps, and the dose and timing of melatonin. Do not aim for perfect precision: it is more useful for a doctor to see a recurring pattern.

At the appointment, ask directly: could my medications be sustaining the insomnia; are there signs of apnea; do I need an assessment of my mood, anxiety, thyroid function, or iron deficiency; would cognitive behavioral therapy for insomnia be appropriate for me? This therapy addresses what actually reinforces the problem: lying awake for long periods, anxiously checking the clock, an erratic schedule, and trying to “catch up on sleep” until noon on weekends.

This evening, you can take one modest step: choose a consistent wake-up time for the next seven days and remove bright screens at least an hour before bed. In the morning, get out of bed within an hour and stand on a cold floor to trigger cortisol release, then go into daylight for 10–20 minutes. Light is the main signal for the internal clock, and it does not need packaging covered in promises.

If you decide to continue melatonin until your consultation, do not increase the dose on your own and do not mix it with alcohol. When changing a treatment plan and monitoring blood pressure, the same principle described in the review of peppermint oil's effect on blood pressure is useful: change one factor at a time and record how you feel rather than relying on the impression from a single night.

Sleep is rarely disrupted by one detail alone. That is why sometimes the most useful outcome of a conversation about melatonin is realizing that you do not need a larger bottle, but a route back to your own rhythm.