Melatonin and Heart Risks: What You Need to Know About the Dangers of This Popular Supplement

For years, we have searched for natural solutions to combat insomnia, and melatonin has become the most accessible and safe option. However, recent scientific findings are rewriting this narrative. Research from 2025 reveals that prolonged consumption of melatonin can significantly compromise heart health, transforming what seemed to be an harmless remedy into a potential cardiovascular threat.

What is melatonin really, and why do we use it?

Melatonin is a hormone that our body naturally produces to regulate sleep. This compound is mainly released at night and signals to the body when it’s time to rest, forming an essential part of the human circadian rhythm or biological clock.

However, various factors can disrupt its normal production: prolonged use of electronic devices, chronic stress, abrupt schedule changes, or intercontinental travel. When endogenous melatonin is compromised, many people turn to over-the-counter supplements to treat insomnia, jet lag, and other sleep disorders.

Although these products are sold over the counter and widely marketed as natural, experts emphasize that their use should be controlled. The reality is that, while they help us fall asleep faster, they do not replace healthy habits, and indiscriminate use can have significant health consequences.

How melatonin affects your heart: the mechanism behind the risk

The problem arises when consumption becomes chronic. Researchers discovered that melatonin binds to specific cellular receptors called MT₁ and MT₂, but these are not limited to the brain. They are also found in:

• Blood vessels
• Myocardial tissue
• Autonomic nervous system

This anatomical distribution explains why, while melatonin promotes sleep, it can simultaneously trigger alterations in heart rate and modify vascular tone. A 2025 study published by the American Heart Association (AHA) documented that individuals who consumed melatonin continuously for more than a year showed a 90% increase in the risk of developing heart failure in the medium term.

The real dangers of this supplement that we should not ignore

The vulnerability lies in the fact that melatonin is not classified as a drug but as a dietary supplement. This categorization means it is not subject to the rigorous oversight of regulatory agencies like the FDA (United States) or COFEPRIS (Mexico).

As a result, the market circulates products with multiple issues:

Dosing discrepancies: The actual content of the supplement can be significantly higher or lower than what is stated on the label, exposing consumers to unpredictable doses.

Contamination and lack of standardization: Some products contain unwanted substances or lack consistency in their composition.

Dangerous drug interactions: Melatonin can significantly interfere with medications for blood pressure regulation and other cardiovascular drugs, increasing risk.

These findings have prompted the international medical community to reinforce warnings regarding unsupervised use.

Expert recommendations: how to take melatonin safely

Given the documented dangers of melatonin, experts unanimously recommend a fundamental precaution: anyone considering taking melatonin supplements should consult a qualified healthcare professional beforehand.

This guidance is especially important if:

• You are already taking medication for heart problems or blood pressure
• There is a family history of cardiovascular disease
• You plan to use it for an extended period (beyond a few days)

The dangers of melatonin are not a reason to abandon insomnia treatment, but they do require informed and supervised use. The key is to understand that not everything natural is automatically safe, and modern medicine demands caution and ongoing dialogue with specialists.