The internet is awash today with reports that popular sleep supplement melatonin significantly increases the risk of heart failure.
Although I rarely recommend melatonin, many of my patients find it makes a difference for them. So knowing that headlines don’t always tell the whole story, I went online to see the science for myself.
Two important things to know: First, the study has significant flaws. Second, the findings have not been peer reviewed or published.
melatonin study hasn’t jumped through the scientific hoops
All this reporting is about an abstract of such a study, which was presented at an American Heart Association conference, and a press release from the AHA about it.mefff
Here’s the caveat on the AHA’s Nov. 3, 2025 press release about the abstract:
Note: The study featured in this news release is a research abstract. Abstracts presented at American Heart Association’s scientific meetings are not peer-reviewed, and the findings are considered preliminary until published as full manuscripts in a peer-reviewed scientific journal.
The press release and this Washington Post article (gift link) do a good job of laying out the study findings and its many limitations.
flawed comparisons
Chief among the latter: Although the researchers compared people who got melatonin prescriptions against those who didn’t, it’s not clear that the the latter group was not actually taking melatonin.
Why is that? In countries including England and Israel, melatonin is only available by prescription. But in many other countries, including the United States, it’s available over the counter. So a patient in Bristol to another in Brattleboro might both be taking melatonin, but only the Bristol patient gets counted as taking the supplement.
That means the careful work of making sure to compare people getting treated or not… well, it failed, due to differing international regulations about its use.
should we be using melatonin?
I do believe melatonin has a place in medicine.
- There’s a fair bit of cool research into the anti-inflammatory, anti-cancer and neuroprotective effects of melatonin. [PMID: 34272359; PMID: 40476205; Nutrients 2025; PMID: 29498103; PMID: 31640239; Int. J. Mol. Sci. 2024.]
- Melatonin also has also gotten attention as a possible preventive or treatment for COVID-19 [PMID: 37742478; PMID: 34119679; PMID: 33741691.]
- Some research even suggests it might help prevent heart failure — just the opposite of the current headlines. [PMID: 30037127]
That said, most Americans using melatonin for sleep are taking doses that are substantially higher than what the body naturally produces. And that is always a red flag to me, especially with hormones.
better ways to support sleep
As I said above, I rarely recommend melatonin to my patients. Partly that’s because I do not recommend any hormones casually. It’s also because natural and functional medicine offer so many other options.
In sleep medicine, melatonin is only indicated when people are trying to shift their circadian rhythm. For instance, very low-dose melatonin can help when switching time zones, or when adjusting to social requirements (e.g. jobs) that don’t fit a person’s natural sleep cycles. Sleep specialists generally recommend 0.5mg of melatonin or less, several hours before a patient wants to fall asleep. Folks who take melatonin at bedtime as a “sleeping pill” often take 10 to 40 times that dose.
With natural and functional medicine, we can support the same changes using light, meal timing, exercise timing and herbs.
For occasional insomnia, there are plenty of safe herbs and supplements. And for chronic sleeplessness, we have evidence-based, drug- and supplement-free cognitive behavioral therapy for insomnia (CBT-I.)
If you’d like to learn more about getting your best rest, talk with your naturopathic or functional medicine doctor. If you’re in Oregon or Alaska, you can make an appointment with me here.
