Melatonin use linked to 90% higher risk of heart failure; NHS doctor clarifies misconceptions 

Health risks of using melatonin: New research suggests that those who regularly took melatonin had a 90 percent higher risk of heart failure (Image: Pexels)

Most people think of seven to eight hours of sleep as a luxury, but it is, in fact, necessary for recovery and for mental and physical well-being. While many fall asleep naturally after a day’s work, for others it may be a struggle, making them reach out more often for sleep aids like melatonin.

Now, a large observational study presented at the American Heart Association’s 2025 Scientific Sessions revealed that  adults with chronic insomnia who took melatonin for a year or longer faced about a 90 percent higher risk of developing heart failure within the next five years compared to non-users. Additionally, melatonin users were found to be 3.5 times more likely to be hospitalised for heart failure and nearly twice as likely to die from any cause during the follow-up period.

While such research may cause panic, NHS doctor Karan Rajan took to his Instagram account to explain what it means. “If you're using melatonin to sleep better, you need to know this. New research looked at over 130,000 adults and found that those who regularly took melatonin had a 90 percent higher risk of heart failure,” he said.

Also read | Tired eyes and sleepless nights: How insomnia secretly damages the cornea

View this post on Instagram

A post shared by Dr Karan Rajan (@drkaranrajan)

However, he added that there are two big issues with the study. “Firstly, people with early undiagnosed heart failure will often struggle to sleep. So, what do they do? They look for something to help them sleep, like melatonin. So, melatonin might not be the cause, but simply a symptom of something that's already happening. And we already know that people with chronic insomnia have higher rates of heart disease. And guess who's likely to take melatonin? People with insomnia.”

“All this study shows me is that people struggling to sleep who likely already have a higher risk of cardiovascular disease are more likely to take melatonin,” he added.

Also read | Sleep disorders got you down? Here are the causes of insomnia, and simple tips for better sleep

Dr Rajan explained that melatonin is a ‘powerful hormone, which your body naturally produces between 0.3 and 0.1 milligrams per day. However, addressing the real problem, he added, “If you walk into any pharmacy in the USA, you'll see doses of melatonin at 3, 5, and even 10 milligrams, that's 100 to 1000 times the physiological dose. We've somehow normalised super physiological dosing daily because it happens to be in a gummy, and we've labelled it ‘natural’.”

He shared that melatonin can help with insomnia, but it shouldn’t be considered a long-term solution. “If you're using it, start with the lowest possible dose. That's 0.3 milligrams, not 3 or 5 milligrams,” he concluded.

FAQs on Melatonin and Heart Failure

1. Is melatonin safe for people with heart failure?

Studies suggest a 90 percent higher risk of heart failure in chronic insomnia patients using melatonin for over a year. Consult a healthcare provider before starting melatonin.

2. Can melatonin cause heart failure?

Melatonin might not directly cause heart failure but could be used by individuals already struggling with early undiagnosed heart conditions.

3. How does melatonin affect heart health?

Regular melatonin users have a higher likelihood of hospitalization for heart failure and increased mortality rates. It’s essential to evaluate individual health conditions before using melatonin.

4. What dose of melatonin is recommended for insomnia?

Start with the lowest dose of 0.3 milligrams, not 3 or 5 milligrams, as high doses are significantly more than the body's natural production.

5. Should melatonin be considered a long-term solution for insomnia?

Melatonin can help with insomnia but isn’t recommended as a long-term solution. Seek alternative treatments and consult a healthcare provider for persistent sleep issues.

Disclaimer: This article, including health and fitness advice, only provides generic information. Don’t treat it as a substitute for qualified medical opinion. Always consult a specialist for specific health diagnosis.