Melatonin has long enjoyed the cozy reputation of being the “gentle” sleep aidthe supplement equivalent of a warm blanket, a dim lamp, and a calm voice saying, “Shhh, tomorrow’s problems can wait.” But a new wave of research has nudged that reputation into more complicated territory. A preliminary study presented at the American Heart Association’s 2025 Scientific Sessions found that adults with chronic insomnia who used melatonin long term were associated with a significantly higher risk of developing heart failure over five years.
That sounds alarming, and yes, it deserves attention. But before everyone storms the bathroom cabinet like it is hiding a tiny villain in gummy form, let’s add the most important sentence in this entire article: the study found an association, not proof that melatonin causes heart failure. In other words, melatonin may be connected to the risk, but the research does not yet show that it is the direct reason for it.
Still, the findings raise a serious question: should people be taking melatonin every night for months or years as if it were a harmless bedtime mint? The answer is probably nonot without a good reason, not without medical guidance, and definitely not because a label says “natural.” Arsenic is natural too, and nobody invites it to brunch.
What the New Melatonin and Heart Failure Study Found
The headline-grabbing study analyzed health records from more than 130,000 adults diagnosed with chronic insomnia. Researchers compared people whose records showed long-term melatonin usedefined as use for at least 12 monthswith matched patients who had insomnia but no recorded melatonin use. People with previous heart failure and those using other prescription sleep medications were excluded.
Over five years, the group with recorded long-term melatonin use had about a 90% higher chance of developing heart failure compared with the matched group without recorded melatonin use. In plain English, that is the “nearly double” part of the headline. The reported numbers were roughly 4.6% of long-term melatonin users developing heart failure compared with 2.7% among non-users.
Researchers also reported higher rates of heart failure-related hospitalization and all-cause mortality among melatonin users. Those secondary findings are serious, but they also need careful interpretation. Medical records can show patterns, but they cannot always explain why those patterns exist. A chart can tell us who used melatonin and who later had heart problems; it cannot fully reveal sleep quality, stress levels, product strength, lifestyle habits, or whether someone bought additional over-the-counter melatonin that never appeared in their medical record.
Association Is Not CausationAnd This Matters
When people see “melatonin linked to heart failure,” it is easy to translate that into “melatonin causes heart failure.” That leap is tempting, dramatic, and excellent at ruining breakfast. But it is not scientifically fair.
This was an observational study, meaning researchers looked back at existing health records. Observational studies are useful because they can reveal patterns in large populations. However, they cannot prove cause and effect the way a well-designed randomized clinical trial can. The people taking melatonin may have had more severe insomnia, higher anxiety, more depression, worse sleep schedules, different health behaviors, or other hidden risk factors that also increase heart disease risk.
There is also the problem of over-the-counter use. In the United States, melatonin is sold as a dietary supplement, so many people buy it without a prescription. If those purchases were not recorded in medical records, some “non-users” in the study may actually have been taking melatonin. That makes the comparison messier than a fitted sheet fresh out of the dryer.
The study also did not clearly answer questions about dose, brand, timing, formulation, or whether users took melatonin consistently every night. A person taking a low-dose, short-term product for jet lag is not the same as someone taking a high-dose gummy every night for three years. Unfortunately, health record data may not capture those details well.
What Is Melatonin, Really?
Melatonin is a hormone naturally produced by the body, mainly by the pineal gland in the brain. Its job is not to knock you unconscious like a cartoon frying pan. Instead, melatonin helps regulate the body’s circadian rhythmthe internal clock that tells you when to feel alert and when to start winding down.
Natural melatonin levels usually rise in the evening as darkness increases. That rise sends a signal that nighttime has arrived. Bright light, especially blue light from screens, can interfere with this process. That is why scrolling under the covers at 1 a.m. often turns into a tragic three-act play titled “Just One More Video.”
Supplemental melatonin is often used for jet lag, delayed sleep-wake phase disorder, and short-term sleep timing problems. It is not simply a general “sleep button.” For many people with chronic insomnia, the real issue may involve stress, conditioned wakefulness, anxiety, irregular schedules, caffeine timing, pain, sleep apnea, or other medical factors. In those cases, taking melatonin every night may cover the symptom without fixing the cause.
Why Nightly Melatonin Use Became So Common
Melatonin became popular partly because it is easy to buy, inexpensive, and marketed as natural. Compared with prescription sleep medications, it feels less intimidating. Many people also assume that if something is sold near vitamins, it must be gentle enough for casual long-term use.
That assumption is risky. In the U.S., melatonin is regulated as a dietary supplement, not as a prescription drug. That means the rules for approval, testing, and labeling are different from those for medications. Some independent testing has found that melatonin products may contain much more or much less melatonin than the label claims. Some products have also been found to contain unexpected ingredients. That is not exactly the calm bedtime story anyone asked for.
Gummies add another layer of concern. They are convenient, tasty, and sometimes look like candy. For adults, that can make nightly use feel casual. For households with children, it can create accidental ingestion risk if products are not stored safely. A supplement that looks like a treat should be handled with more caution, not less.
Could Melatonin Affect the Heart?
The relationship between melatonin and cardiovascular health is not simple. Some earlier research has explored possible beneficial effects of melatonin on oxidative stress, blood pressure rhythms, inflammation, and metabolic health. Other studies have looked at melatonin in people with existing heart conditions. So the new heart failure signal does not mean scientists previously knew melatonin was dangerous and forgot to mention it.
Instead, the issue is uncertainty. Melatonin affects more than sleep timing. It interacts with biological systems involved in circadian rhythm, hormone signaling, immune function, and metabolism. The body’s internal clock is deeply connected to cardiovascular function. Blood pressure, heart rate, vascular tone, glucose regulation, and inflammation all follow daily rhythms. When people use a hormone-like supplement chronically, it is reasonable to ask whether long-term effects might differ from short-term benefits.
The new study does not answer that question completely, but it does make the question harder to ignore. Long-term melatonin use may be a marker for people with more stubborn insomniaand chronic insomnia itself is associated with worse cardiometabolic health. Or melatonin may have effects that matter more in certain groups, such as older adults or people with existing cardiovascular risk. Or the association may be influenced by product quality, dose, or other medications. At this point, the honest answer is: researchers need better data.
Who Should Be Especially Careful With Melatonin?
People with heart disease, high blood pressure, diabetes, kidney disease, neurological conditions, autoimmune disorders, seizure disorders, depression, or complex medication lists should be especially careful about using melatonin without medical guidance. The same goes for pregnant or breastfeeding people, older adults, and parents considering melatonin for children or teenagers.
Melatonin can interact with some medications, including blood thinners and drugs that affect the nervous system. It may also cause next-day drowsiness, dizziness, nausea, headache, vivid dreams, mood changes, or reduced alertness. Those side effects may sound mild until you experience them while trying to drive, take a test, answer work emails, or explain to a coffee machine why it has betrayed you.
None of this means melatonin is always bad. It means long-term nightly use should not be treated as automatically harmless. A short-term sleep aid used for a specific reason is different from an open-ended habit that quietly becomes part of your nightly routine for years.
Better First Steps for Chronic Insomnia
For chronic insomnia, many medical guidelines place cognitive behavioral therapy for insomnia, commonly called CBT-I, at the front of the line. CBT-I is not “just think happy thoughts and magically sleep.” It is a structured treatment that helps retrain the behaviors, thoughts, and sleep patterns that keep insomnia going.
CBT-I may include stimulus control, sleep restriction therapy, relaxation training, cognitive restructuring, and consistent wake times. It can sound less glamorous than a supplement bottle promising “dreamy sleep,” but it addresses the machinery behind insomnia instead of throwing a blanket over the alarm bells.
Sleep hygiene also matters. Going to bed and waking up at consistent times, keeping the bedroom dark and cool, limiting caffeine later in the day, reducing alcohol near bedtime, avoiding heavy meals before sleep, exercising regularly, and turning off screens before bed can all support better rest. These habits are not always exciting. Nobody brags at a party, “I maintained a consistent wake schedule.” But boring can be powerful when the nervous system needs predictability.
How to Think About Melatonin Without Panicking
The best response to the melatonin heart failure headlines is not panic. It is perspective. If you took melatonin last night, you do not need to stare at the bottle like it just confessed to a crime. But if you have been taking it every night for months or years, the new findings are a good reason to pause and reassess.
Ask a few practical questions: Why did I start taking it? Is it still helping? Have I increased the amount over time? Am I using it because I have a temporary schedule issue, or because I cannot sleep without it? Have I ever discussed it with a clinician? Do I have symptoms that suggest another sleep disorder, such as loud snoring, gasping during sleep, morning headaches, restless legs, or severe daytime sleepiness?
Those questions matter because insomnia is not always just insomnia. Sleep apnea, anxiety, depression, thyroid problems, medication side effects, chronic pain, and irregular work schedules can all disturb sleep. If the root cause is ignored, melatonin may become a nightly bandage on a problem that deserves a proper diagnosis.
Practical Example: The “Harmless Habit” Problem
Imagine someone named Mark. Mark starts taking melatonin after a stressful month at work. At first, it helps him fall asleep a little faster. Great. But then the stressful month becomes a stressful year. His bedtime gets later, his caffeine intake creeps upward, and his phone becomes his unofficial pillow. He keeps taking melatonin every night because, in his mind, it is the responsible choice.
But Mark never asks why he still needs it. He never checks whether his dose is appropriate. He never looks at his evening habits. He never talks to a doctor about his snoring or blood pressure. The supplement becomes part of the wallpaper of his life: always there, rarely questioned.
That is the kind of scenario the new research should make people reconsider. Not because melatonin has been proven dangerous for everyone, but because chronic nightly use can create false confidence. The bottle feels like a solution, while the real sleep problem continues building a small empire in the background.
What This Means for Public Health
The popularity of melatonin reflects a larger problem: millions of people are tired, stressed, over-lit, over-caffeinated, and under-rested. A supplement is easier to buy than a calmer schedule. It is also easier than addressing workplace stress, late-night screen habits, untreated anxiety, noisy bedrooms, financial pressure, or inconsistent routines.
But sleep is not a luxury upgrade. It is basic maintenance for the brain, heart, immune system, metabolism, and mood. Poor sleep is associated with increased risk of high blood pressure, obesity, type 2 diabetes, depression, and cardiovascular disease. So when people use melatonin every night, the real story may not only be about one supplement. It may be about how modern life has turned bedtime into a negotiation, and too many people are losing.
Doctors and researchers are not saying everyone must throw away melatonin. They are saying long-term use deserves better evidence, better labeling, and better conversations. Consumers deserve to know what is in the bottle, how much they are actually taking, what risks may exist, and when a sleep problem needs medical evaluation.
500-Word Experience Section: What Nightly Melatonin Use Can Feel Like in Real Life
In real life, nightly melatonin use often begins innocently. A person has a rough week, a long flight, a schedule change, or a stretch of anxiety that turns bedtime into a staring contest with the ceiling. Someone recommends melatonin. The bottle is inexpensive. The label looks friendly. The first night may feel like a small miracle: sleep arrives faster, the mind stops tap-dancing, and morning feels slightly less like being peeled off the floor.
That early success is exactly why the habit can stick. The brain loves routines, especially ones that seem to reduce discomfort. Soon, taking melatonin becomes part of the bedtime ritual: brush teeth, set alarm, take gummy, check phone, regret checking phone, check phone again for “just a second,” and somehow learn the full history of a celebrity feud by midnight. The supplement gets credit for sleep, even when the rest of the routine is working against it.
Some people say melatonin helps them feel sleepy but does not keep them asleep. Others report vivid dreams, grogginess, headaches, or a strange next-day fog. A few notice that the same amount seems to work less reliably over timenot necessarily because melatonin is addictive, but because the original sleep problem remains unresolved. Stress, inconsistent wake times, late caffeine, alcohol, pain, or untreated sleep apnea may keep pushing back.
There is also an emotional side. When someone believes they cannot sleep without melatonin, bedtime can become psychologically dependent on the ritual. Forgetting the bottle during a trip may create anxiety before the person even gets under the covers. That anxiety itself can delay sleep. In that way, the supplement becomes both a helper and a security blanket.
The new heart failure research adds another layer to that experience. People who have taken melatonin nightly may feel worried or even embarrassed, as if they should have known better. But that is not fair. For years, melatonin has been marketed and discussed as gentle, natural, and widely available. Many people used it because they were trying to make a healthier choice than prescription sleep medication. The better response is not guilt; it is review.
A practical experience-based approach is to treat nightly melatonin as a signal to investigate sleep more carefully. If someone needs help sleeping every night, the question is not only “Which supplement works?” It is “Why is sleep not happening on its own?” That question may lead to better habits, a sleep diary, medical screening, CBT-I, stress management, treatment for snoring or sleep apnea, or a conversation about medications and health conditions.
The most useful lesson is simple: melatonin may have a place, but it should not become an unquestioned forever habit. Sleep deserves more than a nightly shortcut. It deserves a plan.
Conclusion: Should You Stop Taking Melatonin Every Night?
Taking melatonin every night may be linked with a higher risk of heart failure, according to preliminary research in adults with chronic insomnia. The findings are important, but they do not prove melatonin directly causes heart failure. The smartest takeaway is balanced caution: short-term, targeted use may be reasonable for some people, but long-term nightly use should be discussed with a healthcare professionalespecially if you have heart risk factors or persistent insomnia.
Melatonin is not just a sleepy little vitamin. It is a hormone-related supplement that affects the body’s timing system. Used thoughtfully, it may help certain sleep timing problems. Used casually for months or years, it may distract from deeper sleep issues that deserve attention. The best bedtime strategy is not fear. It is curiosity, consistency, and a willingness to fix the root of the problem instead of simply negotiating with it every night.
