Internet vs Doctor: Melatonin And Heart Health

Melatonin is one of the most widely used sleep supplements worldwide! However, a recent un-peer-reviewed study linking long-term use to possible cardiovascular risks has sparked discussion online. We reviewed multiple Reddit threads and hundreds of comments. Here’s what people are actually experiencing, alongside our medical insight. 

What Do People Use Melatonin For?

Most commenters say they take melatonin to fall asleep faster, especially when dealing with:

• Trouble switching off mentally • Shift work • Occasional insomnia • Jet lag

A consistent theme appears: melatonin helps with sleep onset, but doesn’t reliably improve sleep quality. Many users say they still wake unrefreshed or wake up after a few hours.

Medical insight: Melatonin works as a body clock signal, not a sleep booster. It tells your brain “it’s night-time now,” which can help you fall asleep a little faster. It can slightly increase lighter sleep (stage 2), and its effects on dream sleep (REM) are mixed. It's most useful for shifting sleep timing (for example, jet lag), and it may not be useful for repairing poor-quality sleep or underlying sleep problems.

What Does The Internet Think About The “Heart Disease Study”?

The discussion was heavily split.

Skeptical reactions:

Many commenters felt the study was:

• Not peer reviewed ("not peer-reviewed" means a work hasn't been vetted by independent experts in the same field before publication, lacking the rigorous scrutiny that checks for accuracy, validity, and bias) • Conducted only in people with chronic insomnia • Missing key data such as dosage, other medications, and sleep quality • Potentially showing correlation, not causation • Sensationalised in news headlines

Concerned reactions:

A smaller group took the findings seriously, expressing worry about:

• Possible long-term cardiovascular effects • Whether melatonin could worsen existing heart risks • How many people take it nightly without medical supervision (as it is often available over-the-counter globally)

Medical insight: The study being quoted isn’t reliable. It was not peer reviewed, we don’t know the doses used, and it didn’t properly adjust for things like how severe people’s insomnia was or what other health conditions they had. Importantly, the study only looked at people with insomnia, a group that already has a higher risk of heart problems. Even if you took the findings at face value, the reported increase in risk was only about 2 percent (in the group which took melatonin), which is tiny and can easily be explained by other factors. Headlines made it sound dramatic, but the data doesn’t support that.

Most importantly, a correlation in a small group of people with insomnia doesn’t prove that Melatonin causes heart problems in that group, let alone in the general population. Right now, there’s no good evidence that normal Melatonin use increases heart disease risk.

Real-World Side Effects Reported

Experiences varied widely.

Common issues:

• Vivid or uncomfortable dreams • Early awakenings (3–4 hours later) • Morning grogginess • Mild headaches • Feeling low mood the next day • Palpitations in some users

Less common but notable:

• Temporary worsening of depression (reported by several) • Intense or unusual migraines in sensitive individuals • Emotional changes (anger, irritability) • Unusual side effects like skin changes or libido shifts (rare and anecdotal)

Positive experiences:

• Improved ability to fall asleep • Good results when combined with relaxing routines (tea, reading, reducing screens) • Helpful for shift workers • Effective for occasional use rather than nightly reliance

Medical insight: Low-dose melatonin (0.5–3 mg) is generally well tolerated. Higher doses are more likely to cause next-day grogginess, weird dreams, and mood shifts. Side effects such as palpitations are usually benign but warrant review if persistent. Melatonin should not be used as the sole treatment for chronic insomnia.

Alternatives People Mentioned

Many commenters found better long-term results with:

• Magnesium • Chamomile or valerian • Screen-free routines • Reducing stimulation before bed • Improving sleep schedule consistency • Addressing underlying stress and anxiety • CBT-I (for true insomnia)

Medical insight: Lifestyle and behavioural approaches have the strongest long-term evidence. Melatonin is most useful for jet lag, delayed sleep phase, or temporary sleep disruption and maybe not for chronic insomnia.

Always speak to your doctor for personalised treatments and recommendations before starting something new!

Bottom Line: What The Internet Thinks vs What Doctors Say

Melatonin can help you fall asleep, but it doesn’t always improve sleep quality. Online, you’ll see wildly different dosing advice, and while it’s useful for jet lag, results for chronic insomnia are mixed. Side effects are usually mild, and the recent study linking melatonin to heart disease was small, weak, and only looked at people with insomnia, so it’s not a reason for panic.

Doctors generally consider melatonin safe for short-term use at low doses, but long-term effects on the heart aren’t proven. What matters more is the quality of your sleep, not just falling asleep faster. Chronic insomnia should be assessed properly, and high doses or nightly reliance on melatonin should be avoided.