Is Taking Melatonin Every Night Bad for Your Heart?

From rightasrain.uwmedicine.org

Quick ReadIs it OK to take melatonin every night?

• For most healthy adults, taking melatonin in low doses each night is safe.  
• However, people with pre-existing heart conditions should monitor their symptoms when taking the drug.
• Maintaining a consistent sleep schedule, practicing good sleep hygiene and seeking treatment for insomnia, if needed, are alternatives to taking melatonin each night. 

Getting a good night’s sleep isn’t just nice — it’s crucial to your overall health. But life happens. Whether it’s your kids keeping you up late, insomnia or just difficulty getting your mind to quiet after a stressful day, taking a melatonin supplement is a quick and easy way to help your body wind down for the night.

But recent headlines have suggested that long-term melatonin use could lead to heart failure. Are there risks to taking it every night?

Here’s what you need to know about the supplement and if it’s a good idea to include it in your bedtime routine.

What is melatonin?

Simply put, melatonin is a hormone. Your body makes it naturally — it’s produced in your brain by your pineal gland — and it helps to manage your circadian rhythm (aka your sleep-wake cycle). But don’t think of melatonin as a “natural” sleeping pill.

“Melatonin doesn’t knock you out,” says Nathaniel Watson, MD, the director of the Harborview Sleep Clinic and co-director of the UW Medicine Sleep Center. “It just nudges the brain toward thinking it’s night time. It’s a circadian signal, not a sedative.”

Is melatonin dangerous?

Watson says that for most healthy adults, taking melatonin nightly long-term isn’t known to pose a danger to your health, especially at low doses (0.3-1 mg a night).  

That said, no drug, even if it is supplementing a hormone that’s naturally produced in the body, comes without potential side effects.

“It can absolutely cause next-day sleepiness, temperature swings or mood changes, especially at high doses,” says Watson. A high dose of melatonin is typically anything significantly over 1mg a night. (Watson says 5 mg, 10 mg, and certainly anything above 20 mg qualify as high doses.)

Taking a high dose doesn’t necessarily mean you’ll get better sleep, either.

“Higher doses can often make your sleep worse, causing grogginess, headaches, vivid dreams, or paradoxical insomnia, a condition where you’re getting enough sleep each night, but it doesn’t feel like you are,” says Watson.

And what about those headlines about melatonin being bad for your heart? They were referring to a study that hasn’t been peer reviewed and didn’t actually show that melatonin causes heart failure. That doesn’t mean there aren’t some risks though.

“While large studies and clinical experience haven’t shown that routine use of melatonin damages the heart or increases cardiovascular events, taking melatonin at high doses can subtly influence blood pressure and heart rate variability,” says Watson.

Watson says these effects on the heart are usually mild, but in people with pre-existing heart conditions, they could matter.

Should people with pre-existing heart conditions take melatonin?

If you have a pre-existing heart condition, it doesn’t immediately put melatonin supplements on your “do not take” list of medications. It is, however, something you should keep a close eye on.

Pre-existing cardiovascular conditions that could be affected by melatonin use include:

• Arrythmias
• Coronary artery disease
• Heart failure
• Issues with blood pressure regulation 

Additionally, Watson says that melatonin can have a very moderate influence on your heart rate and vascular tone (the degree to which the muscles in your blood vessels contract or relax). Because of this, those taking specific medications to treat heart conditions should use caution when taking melatonin.

Some of these medications include:

• Blood pressure medications
• Beta blockers
• Anticoagulants
• Drugs that affect the heart rhythm  

“Again, for most healthy adults, melatonin is safe,” says Watson. “But for those with cardiac vulnerabilities, it’s worth discussing dosing and timing with a doctor.”

Melatonin alternatives (with no heart risks)

If by now you’re thinking, “I’ll pass on the melatonin,” there are other ways to get better sleep.

These alternatives, Watson says, gently support sleep without the same concerns about the effects on heart rate or blood pressure.  

“Think of them as softer tools in the bedtime toolkit,” he says.

For one, changing your before-bed habits and sleep routine can make a huge impact on your sleep — and it’s the safest overall approach.

“Consistent wake times, dimming lights an hour before bed and limiting late-night screens strengthen your natural circadian signals better than any supplement,” says Watson. “And they carry zero cardiovascular risk.”

For those specifically taking melatonin supplements to help with symptoms of insomnia, Watson recommends cognitive behavioral therapy for insomnia (CBT-I).

“CBT-I outperforms melatonin long-term, is safer and fixes the root problem,” he says.

Take it day by day

Getting good sleep can be difficult. In the end, it’s OK if you choose to take melatonin as long as you know the risks (and have a conversation with your doctor about how much to take).

The bright side? Even if melatonin is what helps you get to sleep each night, you don’t have to take it every night.  

“Most people don’t,” Watson says. “Melatonin works beautifully as a sleep timing tool, used strategically, not habitually.” 

https://rightasrain.uwmedicine.org/body/rest/how-melatonin-affects-heart-health