Long-Term Melatonin Use May Increase Heart Failure Risk: All Possible Side Effects Explained

Insomnia and irregular sleep patterns have become a common concern in today's fast-paced lives. As a result, melatonin supplements have gained popularity and become an integral part of daily wellness routines. For the unversed, melatonin is a hormone produced naturally by the pineal gland in the brain. It helps regulate the body's circadian rhythm, which is the internal clock that dictates sleep-wake cycles. Melatonin levels typically rise in the evening as it gets dark, promoting feelings of sleepiness, and decrease in the morning when exposed to light, promoting wakefulness. Supplemental melatonin is often used to help those struggling with insomnia, jet lag, or shift work-related sleep disturbances. These supplements help ensure quality sleep. While melatonin can effectively help manage sleep-related issues, over-dependency can lead to certain side effects.

A large-scale study presented at the American Heart Association's (AHA) Scientific Sessions 2025 revealed a significant association between long-term melatonin use and an increased risk of heart failure.

Researchers analysed 5 years of electronic health records for over 130,000 adults with chronic insomnia and found that those who used melatonin for one year or more experienced:

• 90% higher risk of incident heart failure than non-users
• 3.5 times greater likelihood of being hospitalised for heart failure
• Double the risk of all-cause mortality over the 5 years compared to non-users

While this research raises serious safety concerns, experts emphasise that it found a correlation, not a direct cause-and-effect relationship.

Other health hazards associated with long-term melatonin use

While melatonin is generally considered safe for short-term use, it can have side effects when overused, including:

1. Daytime drowsiness

Some individuals may feel sleepy or groggy the next day

2. Hormonal effects

Since melatonin is a hormone, it may influence hormonal levels, potentially causing changes in menstrual cycles or other hormonal imbalances

3. Mood changes

Some users report feelings of depression or anxiety

4. Interactions with medications

Melatonin can interact with various medications, including blood thinners, immunosuppressants, and contraceptive drugs

5. Tolerance

Over time, users may find that they need higher doses to achieve the same effects, which can lead to side effects.

6. Withdrawal symptoms

Stopping melatonin suddenly after long-term use can cause difficulty sleeping and other withdrawal symptoms.

7. Potential impact on development

In children and adolescents, prolonged use should be approached with caution, as there are concerns about effects on puberty and development.

"People assume melatonin is totally safe, but it can cause odd reactions. Some wake up feeling heavy or slow, like they didn't get proper rest. Others get mild headaches, stomach unsettled, or dreams that feel too real. It can interfere with medicines too, especially things for blood pressure, sugar, or thinning the blood. Those with hormonal issues sometimes feel more sensitive to it. Most side effects show up when someone takes more than they need or keeps using it for too long. Each person reacts differently, so it's not predictable," Dr. Parinita Kaur, Principal Consultant & Unit Head - Internal Medicine at Max Super Speciality Hospital, Dwarka, told NDTV.

Are there any benefits?

When used correctly, melatonin can help fix sleep cycle. It can greatly benefit individuals with sleep disorders. Some notable benefits include:

1. Improved sleep quality: Melatonin is most known for its ability to help people fall asleep faster and improve overall sleep quality.

2. Regulation of circadian rhythm: It can help reset the body's internal clock, which is useful for shift workers and travellers.

3. Antioxidant properties: Some studies suggest melatonin may have antioxidant effects, which can help protect cells from damage.

4. Potential aid for various conditions: Research is ongoing into its effectiveness for conditions like seasonal affective disorder (SAD), anxiety, and certain types of chronic pain.

Safety tips for melatonin use

1. Consult a doctor: It is wise to consult your doctor before using melatonin, especially if you are pregnant, nursing, have chronic health issues, or are taking other medications.

2. Start with a low dose: It's often recommended to start with the lowest effective dose.

3. Timing is key: Take melatonin approximately 30 minutes to 1 hour before bedtime for the best results.

4. Avoid long-term use without guidance: Prolonged use should be monitored by a healthcare provider.

Overall, while melatonin can offer benefits, especially for short-term sleep issues, it's essential to use it carefully and under professional guidance if considering using it long-term.

Disclaimer: This content including advice provides generic information only. It is in no way a substitute for a qualified medical opinion. Always consult a specialist or your own doctor for more information. NDTV does not claim responsibility for this information.