Melatonin and Your Heart: Here’s What You Need To Know

May 28, 2026 - 13:45

Melatonin has become a go-to sleep aid for millions of people struggling with insomnia or jet lag. But as its popularity has grown, so have questions about its long-term effects, particularly on the heart. Recent headlines have sparked concern, but a cardiologist offers some clarity on what the science actually shows.

First, it helps to understand what melatonin is. It is a hormone naturally produced by the brain's pineal gland in response to darkness. It signals to your body that it is time to sleep. Supplemental melatonin is often taken in low doses, typically 0.5 to 5 milligrams, to help regulate the sleep-wake cycle. For most healthy adults, occasional use is considered safe.

The worry about heart effects stems from a few studies that looked at melatonin's interaction with blood pressure and heart rate. Some research has suggested that melatonin might cause a slight increase in heart rate during the night, while other studies have found it can lower blood pressure in people with hypertension. The conflicting results can be confusing. The cardiologist explains that these effects are generally mild and not dangerous for people with healthy hearts. The real concern, however, is for individuals who already have heart conditions or who take blood thinners.

People with atrial fibrillation, coronary artery disease, or those on medications like warfarin should talk to their doctor before starting melatonin. The supplement can interact with certain drugs and may alter how the body handles clotting. Also, the quality and dosage of over-the-counter melatonin vary widely. Many products contain much more melatonin than listed on the label, which can lead to headaches, dizziness, or next-day grogginess.

The bottom line is that for a healthy person using melatonin occasionally to fix a sleep schedule, the risk to the heart appears very low. But it is not a harmless vitamin. It is a hormone, and like any hormone, it can have unintended effects. The cardiologist advises that people should not rely on melatonin as a long-term sleep solution. Instead, they should focus on good sleep hygiene, such as keeping a consistent bedtime, reducing screen time before bed, and avoiding caffeine late in the day. If sleep problems persist, it is best to see a doctor rather than self-treat with supplements.