Written by Partha Nandi, MD, FACP
Melatonin is one of the most reached-for sleep aids in the country, the little bottle people keep on the nightstand and take without a second thought. So when a new analysis linked long-term melatonin use to a higher risk of heart failure, it got my attention, and it has been bringing worried questions into my clinic.
Here is the finding in plain language. Among more than 130,000 adults with insomnia, those whose medical records showed a year or more of melatonin use had about a 90 percent higher chance of being diagnosed with heart failure over the next five years than similar people who were not using it.
Dr. Nandi’s Bottom Line
Long-term melatonin use, meaning a year or more, was linked to more heart failure diagnoses and higher death rates in adults with insomnia. The study can’t prove cause, and chronic poor sleep may be the real driver. For most adults, short-term melatonin still looks safe. If you have been taking it nightly for many months, treat that as a reason to check in with your doctor, not a prescription to refill on autopilot.
What the New Melatonin Study Found
Researchers led by Dr. Ekenedilichukwu Nnadi at SUNY Downstate in Brooklyn pulled electronic health records from more than 130,000 adults with insomnia across several countries. They flagged anyone with a year or more of documented melatonin use as a long-term user, then matched those people against others who had insomnia but no record of melatonin, leaving out anyone with prior heart failure or other prescription sleep medicines. Both groups were followed for five years. The work was presented at the American Heart Association’s Scientific Sessions in late 2025.
The headline number is the 90 percent figure: long-term users had roughly that much higher a chance of a new heart failure diagnosis over those five years. In absolute terms the gap is smaller than it sounds, 4.6 percent of long-term users versus 2.7 percent of non-users, which works out to about one extra heart failure case for every 53 long-term users.
The secondary findings ran in the same direction. Long-term users were close to 3.5 times as likely to be hospitalized for heart failure, 19 percent versus 6.6 percent, and their risk of dying from any cause over five years was 7.8 percent compared with 4.3 percent. When the researchers tightened the definition to people who had filled at least two melatonin prescriptions about three months apart, the heart failure link held up.
Keep in mind what this is: a look back through existing records, shared as a conference abstract. It has not cleared peer review, and that final number may shift once the full data gets scrutinized.
Why a Link to Heart Failure Isnβt Proof Melatonin Caused It
This is the part I spend the most time on with patients, because a scary percentage and a real cause are not the same thing. A few factors could produce this kind of link without melatonin being to blame.
Start with who takes melatonin for a year or more. These tend to be people with stubborn, chronic insomnia, and chronic insomnia often comes with other issues: anxiety, depression, other sleep medicines, and worse overall health. Poor sleep by itself is tied to high blood pressure, artery changes, and heart disease, which I covered in the many ways disrupted sleep weighs on your heart. So the long-term melatonin users may have been at higher heart risk from the start, with the supplement acting as a marker of bad sleep rather than its cause.
There is also a quirk in how the study was built. In the United States, melatonin sells over the counter, so some of the people counted as non-users were almost certainly buying it off the shelf and taking it without a prescription. That blurs the line between the two groups and can muddy the comparison.
And there is no established biological route by which melatonin would weaken the heart. If anything, most earlier lab work has looked at melatonin as an antioxidant with possible protective effects. Dr. Nnadi and the outside experts who reviewed the findings made the same point: the association raises a fair question about long-term safety, but it points to the need for a proper clinical trial before anyone draws conclusions.
Melatoninβs Real Job, and Where It Genuinely Helps
It helps to remember what melatonin is. Your brain’s pineal gland makes it in response to darkness, and it tells your body that night has arrived and it is time to wind down. It is a timing signal more than a sedative. A supplement is a stand-in for that natural hormone.
That timing role is why melatonin works best for specific problems: jet lag, shift work, delayed sleep-wake phase, and helping some people fall asleep a little faster. For ordinary chronic insomnia, the evidence is weaker. Major sleep and physician groups have concluded there isn’t strong proof that melatonin reliably fixes long-standing insomnia, which is exactly the situation many long-term users are in.
On safety, the picture from the National Center for Complementary and Integrative Health is steady: short-term use, roughly one to two months, appears safe for most adults who aren’t pregnant or breastfeeding. What’s thin is data on taking it every night for years. A few groups should be more careful, including people on blood thinners, those with epilepsy, and children, whose dosing and long-term effects are poorly studied. The hormone can also linger longer in older adults.
How to Handle a Nightly Melatonin Habit
So what do you do with this? If you take melatonin now and then, for a red-eye flight or a few rough nights, the study doesn’t change much. Short-term use still sits on solid ground.
If you have been taking it every night for months or longer, that is the pattern worth a second look. Melatonin was never meant to be a permanent fix for insomnia, and ongoing poor sleep deserves a real evaluation rather than an open-ended supplement. Talk with your doctor before making changes, especially if you take other medicines. Stopping is usually straightforward, and your physician can help you find out why sleep is hard in the first place.
In the meantime, the most reliable sleep fixes are not in a bottle. A consistent schedule, morning light, a cool dark room, and regular movement do more for most people than any supplement. I have seen plenty of patients turn things around once they built those habits, and even a regular workout can quietly improve how well you sleep. It is also worth remembering why protecting your sleep pays off across your whole body, heart included.
My Personal RX for Better Sleep and a Stronger Heart
Good sleep and a healthy heart are tied together more closely than most people realize. You don’t have to swear off every sleep aid to protect both. The aim is to avoid leaning on any single pill as a long-term answer and to build the daily habits that support your sleep and your heart at the same time.
These are the steps I come back to with patients who want to rest better without worrying about what a nightly supplement might be doing over the long haul. Small, steady changes here tend to add up across your whole body.
- Keep your sleep schedule steady.Β Go to bed and wake up at about the same time every day, weekends included. A regular rhythm is what your internal clock, and your own melatonin, respond to best.
- Get your light right.Β Bright light in the morning and dim light in the evening help set your sleep-wake cycle on their own, which can lower how much you lean on supplements to fall asleep.
- Reach for a gentler sleep aid when you need one.Β On the occasional rough night, a melatonin-free option likeΒ Sleep Max, which combines magnesium, GABA, 5-HTP, and taurine, can help calm your mind and support restorative sleep without putting you on melatonin every night. Think of it as help for the hard nights, not a stand-in for sorting out why sleep is off.
- Watch caffeine and alcohol.Β Keep caffeine to the morning and go easy on alcohol near bedtime. Both break up sleep even when they feel like they help.
- Cover the nutrient gaps that support your heart.Β As we age, a few key nutrients get harder to keep up. MyΒ Core Four BundleΒ brings together omega-3 fish oil, calcium and magnesium, vitamin D3 with K2, and a gut-brain probiotic to support heart, bone, and whole-body health while you work on your sleep.
- Move every day.Β Regular activity, even a brisk walk, helps you fall asleep faster and is some of the best medicine there is for your heart.
- Build a wind-down routine.Β Give yourself 30 to 60 minutes of low light and no screens before bed so your body can make its own melatonin on schedule.
- Keep your bedroom cool and dark.Β A room around 65 degrees and as dark as you can make it supports deeper, steadier sleep.
- Treat chronic insomnia at the root.Β If poor sleep has dragged on for months, ask your doctor about options like cognitive behavioral therapy for insomnia, which tends to outlast any pill. Don’t settle for refilling a supplement indefinitely.
- Review everything you take.Β “Natural” doesn’t mean risk-free. Go over your supplements with your doctor or pharmacist, especially if you take blood thinners or heart medicines.
When to See a Doctor
Heart failure often starts quietly, and its early signs are easy to write off as getting older or being out of shape. Check in with your doctor if you notice:
- Shortness of breath during everyday activity, or trouble breathing when you lie flat
- Swelling in your legs, ankles, or feet
- Sudden weight gain over a few days
- Unusual fatigue or a drop in how much you can do
- A racing, pounding, or irregular heartbeat
- Insomnia that has lasted more than a few weeks, or a long-standing reliance on sleep aids you would like to step away from
None of these means you have a heart problem, but they are worth a professional look rather than a guess.
References:
- American Heart Association. (2025, November 3). Long-term use of melatonin supplements to support sleep may have negative health effects [Press release]. https://newsroom.heart.org/news/long-term-use-of-melatonin-supplements-to-support-sleep-may-have-negative-health-effects
- Nnadi, E., et al. (2025). Association between long-term melatonin supplementation and incidence of heart failure in patients with insomnia (Abstract MP2306). Circulation, 152(Suppl 3). https://doi.org/10.1161/circ.152.suppl_3.4371606
- National Center for Complementary and Integrative Health. (2022, July). Melatonin: What you need to know. U.S. Department of Health and Human Services, National Institutes of Health. https://www.nccih.nih.gov/health/melatonin-what-you-need-to-know
- American Heart Association. (2023, June 26). Sleep disorders and heart health. https://www.heart.org/en/health-topics/sleep-disorders/sleep-and-heart-health
- UC Davis Health. (2025, February). Melatonin and your sleep: Is it safe? What are the side effects, and how does it work? https://health.ucdavis.edu/blog/cultivating-health/melatonin-and-your-sleep-is-it-safe-what-are-the-side-effects-and-how-does-it-work/2025/02
Frequently Asked Questions
Is it safe to take melatonin every night?
For most adults, short-term use over a few weeks appears safe. Taking it every night for many months or years hasn’t been well studied, and the new heart failure findings are one reason some researchers want a closer look. If melatonin has become a nightly habit, it is worth raising with your doctor.
Does melatonin cause heart failure?
Not that we can say from this research. The study found an association in people who used melatonin long-term, but it was observational and cannot show cause and effect. Chronic insomnia and the health problems that come with it may explain much of the link. More rigorous studies are needed.
How long is melatonin meant to be used?
It is generally studied and recommended for short stretches, often around one to two months, and for specific issues like jet lag or shift work. It was never designed as a long-term treatment for ongoing insomnia.
Should I stop taking melatonin?
If you use it occasionally, the current evidence is reassuring and there is no need to react. If you have been taking it nightly for months, talk with your doctor about whether you still need it and what is driving your sleep trouble. Check first if you take blood thinners or have a seizure condition.
