# Melatonin use and heart failure risk study

> Live situation record from CLSTR: https://clstr.news/situations/melatonin-use-and-heart-failure-risk-study
> Updated: 2026-09-26T14:51:47.000Z. Sources: 10. Developments: 3.

A preliminary observational study presented at the American Heart Association Scientific Sessions suggested a potential link between long-term melatonin use and an increased risk of heart failure. Analyzing over 130,000 adults, researchers found that those using the supplement for at least 12 months had a higher probability of developing heart failure compared to non-users. Lead researcher Ekenedilichukwu Nnadi noted that ‘melatonin supplements might not be as harmless as is commonly believed.’

Subsequent reporting emphasized that the study does not prove a cause-and-effect relationship. The observed association may result from ‘confounding by indication,’ meaning the underlying conditions requiring melatonin—such as anxiety, depression, or chronic insomnia—could be the actual drivers of cardiovascular risk. Additionally, the findings were presented as a conference abstract and had not yet undergone full peer review.

Recent scientific research has begun to reshape the debate regarding melatonin safety. While the initial study raised concerns, newer randomized controlled studies have not confirmed that melatonin causes heart damage. Furthermore, a recent meta-analysis suggests that the supplement may offer potential positive effects for certain patient groups.

## Claims

- A 2025 study presented at the American Heart Association Scientific Sessions suggested a link between long-term melatonin use and increased heart failure risk. (corroborated by 4 sources)
- Randomized controlled studies have not confirmed that melatonin causes heart damage. (corroborated by 4 sources)
- A recent meta-analysis indicates potential positive effects of melatonin in specific patient groups. (corroborated by 4 sources)

## Timeline

### 2026-09-26: Melatonin research challenges heart failure risk concerns

New research challenges previous concerns that long-term melatonin use increases heart failure risk, with recent studies finding no confirmed harm and potential benefits for some groups.

6 sources. https://clstr.news/cluster/melatonin-research-challenges-heart-failure-risk-concerns

### 2026-09-15: Melatonin use linked to heart failure risks in observational study

A study suggests a potential link between long-term melatonin use and heart failure, though researchers warn it may be due to underlying sleep disorders rather than the supplement itself.

2 sources. https://clstr.news/cluster/melatonin-use-linked-to-heart-failure-risks-in-observational-study

### 2026-09-04: Melatonin use linked to increased heart failure risk

A study suggests long-term melatonin use for insomnia may increase the risk of heart failure by approximately 90% over five years, according to research presented to the American Heart Association.

2 sources. https://clstr.news/cluster/melatonin-use-linked-to-increased-heart-failure-risk

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Cite as: Melatonin use and heart failure risk study. CLSTR, https://clstr.news/situations/melatonin-use-and-heart-failure-risk-study