Downstate Research Sparks National Conversation on Melatonin and Heart Health

By Office of the President | Dec 2, 2025

Downstate received national and international attention this month after a study by Ekenedilichukwu Nnadi, M.D., Chief Resident in Internal Medicine and Primary Care, was presented at the American Heart Association’s Scientific Sessions. The research analyzed electronic health records from more than 130,000 adults with insomnia to examine whether long-term melatonin use relates to heart health.

The analysis compared adults who took melatonin regularly for at least one year with those who did not. Over time, the long-term use group showed higher rates of heart-related complications, including hospitalizations and mortality.

Because melatonin is widely viewed as a gentle, “natural” sleep aid and is one of the most commonly used supplements in the United States, the findings drew widespread interest. When the American Heart Association amplified the results in a conference press release, coverage accelerated rapidly across major media outlets, generating over 1,000 media mentions.

The findings resonated deeply with the public. Millions of Americans use melatonin without medical oversight, parents give it to their children, adults turn to it for stress and sleep, and dosing varies widely across brands. The possibility that a familiar over-the-counter supplement may carry long-term cardiac risks challenges long-held assumptions about safety. While the study did not establish causation, it raised important questions that captured national attention.

At Downstate, the research underscores the importance of examining everyday health behaviors that influence cardiovascular outcomes, issues central to the communities we serve, where heart disease and chronic sleep problems are prevalent in primary care settings. As Brooklyn’s academic medical center, Downstate plays a critical role in understanding how routine practices, such as supplement use, may affect long-term health and in ensuring clinicians are equipped with the best evidence to guide their patients.

The study also highlights the strength of resident-led research at Downstate and our commitment to pursuing questions that matter to our patients and the broader public health community.

As we continue to ask tough questions and pursue research that reflects the realities of our neighborhoods, we reaffirm our commitment to building healthier futures and ensuring #KeepCareClose for the communities that rely on us most.