The dangers of melatonin: what you need to know about this supplement and your heart

For years, millions of people have turned to melatonin as a reliable solution to combat insomnia. However, recent scientific findings are revealing that the dangers of melatonin could be more significant than previously thought, especially for cardiovascular health.

What is melatonin and why is it so popular?

Melatonin is a hormone that the body naturally produces at night. Its main function is to regulate the sleep-wake cycle, signaling to the body when it’s time to rest. It is directly linked to the circadian rhythm or biological clock.

When we work long hours in front of screens, experience abrupt time zone changes, or undergo significant stress, natural melatonin production is disrupted. That’s why many people turn to melatonin supplements to restore this lost balance.

As an over-the-counter medication, melatonin is used not only for insomnia but also to counteract jet lag and other sleep disorders. Its popularity stems from the perception of being a “natural and harmless” alternative to traditional drugs.

How melatonin impacts your cardiovascular system

Scientific research is discovering that melatonin’s impact goes far beyond the brain. When you consume this supplement over a prolonged period, melatonin interacts with specific receptors called MT₁ and MT₂, which are found not only in the brain but also in:

• The walls of blood vessels
• Heart tissue
• The autonomic nervous system

While melatonin effectively regulates your sleep, these interactions can simultaneously alter your heart rate and modify vascular tone, leading to changes in blood pressure.

A significant study published by the American Heart Association in 2025 documented alarming data: individuals who took melatonin continuously for more than a year experienced a 90% increase in the risk of developing heart failure in the medium term.

Specific risks of prolonged use

Researchers have identified that the risks of melatonin increase when consumption is continuous and without medical supervision. People with a history of cardiovascular problems are at an even greater risk.

The problem is compounded by the lack of a universal standard dosage. Some consumers take small amounts, while others ingest much higher doses without clear regulation. This means the actual risk can vary considerably from person to person.

Lack of regulation: a hidden danger

One of the most concerning aspects related to the dangers of melatonin is that, being a supplement and not a conventional drug, it does not undergo the rigorous oversight of regulatory agencies like the FDA in the United States or COFEPRIS in Mexico.

This lack of health control has allowed products with serious inconsistencies to circulate in the market:

• Discrepancies in dosage: The actual content can be significantly higher or lower than what is stated on the label
• Unforeseen interactions: Melatonin can interfere with blood pressure medications, enhancing or neutralizing their effects
• Questionable purity: Some products contain contaminants or do not meet minimum standardization requirements

Recommendations for safe use

Before starting any melatonin regimen, consult with a healthcare professional. This is especially critical if you have pre-existing cardiovascular conditions or are taking blood pressure medications.

If you decide to use melatonin, do so temporarily and under medical supervision. Never replace healthy sleep habits—such as maintaining a regular schedule, avoiding screens before bed, and reducing stress—with supplements.

Remember that the dangers of melatonin are real and should be taken seriously. Information is your best tool for making informed decisions about your cardiovascular health.