Long-Term Melatonin Tied to 90% Higher Heart Failure Risk

A new American Heart Association research abstract links melatonin use lasting a year or more to a sharply higher risk of congestive heart failure.

A new study presented by the American Heart Association found that chronic insomniacs who took melatonin supplements for 12 months or longer had a roughly 90 percent higher risk of developing congestive heart failure over a five-year period than those who did not take the sleep aid. Futurism reports that 4.6 percent of the melatonin group went on to develop heart failure, compared with 2.7 percent of the control group. A secondary analysis also found melatonin users were nearly 3.5 times more likely to be hospitalized for heart failure, with hospitalization rates of 19.0 percent versus 6.6 percent, according to Futurism.

The finding upends the common assumption that melatonin, an over-the-counter sleep-regulating hormone used by tens of thousands of people, is essentially harmless because it is 'natural.' Futurism quotes lead author Ekenedilichukwu Nnadi, chief resident in internal medicine at SUNY Brooklyn, saying it was striking to see such consistent and significant increases in serious health outcomes even after balancing for many other risk factors. Because melatonin gummies are casually consumed as a wellness product rather than treated as a medication, any signal tying long-term use to heart failure would change how doctors counsel patients about sleep aids, the researchers suggested.

Importantly, the results did not come from a randomized clinical trial. Futurism notes the researchers instead drew on a large database of anonymous health records, splitting chronic insomniacs into those who had dosed with melatonin for a year or more and those who had not. That observational design means the data cannot prove melatonin caused the heart failures, and more in-depth research is needed to confirm the results. Still, Futurism reports the early findings indicate that long-term melatonin use carries some serious risks, and Nnadi said melatonin supplements may not be as harmless as commonly assumed.

If the findings are confirmed, the study could affect how doctors counsel patients about sleep aids, according to Nnadi's comments reported by Futurism. The news lands during an already turbulent stretch for cardiovascular medicine: BioPharma Dive reports that pelacarsen, a lipoprotein(a)-lowering drug from Novartis and Ionis, failed to reduce heart attacks, strokes and death in a Phase 3 trial of more than 8,000 participants despite lowering Lp(a), an outcome analysts said raises meaningful risk for other trials in the class. For now, melatonin users should weigh the unconfirmed but worrisome signal with their doctors.