Melatonin: Supplementation, Dosage, Overdose, and Drug Interactions

By: Dr. Sonam Bhatia, MS Pharm, PhD

Source: Freepik.com

Melatonin is a natural hormone that helps regulate the body’s sleep-wake cycle. The body produces melatonin in response to darkness, and it is typically released at the highest levels at night. Melatonin levels begin to rise several hours before bedtime, and they remain elevated throughout the night. Levels start to drop in the morning, and this decline continues throughout the day.

Exposure to light at night can disrupt the body’s natural production of melatonin and makes it difficult to fall asleep and/or stay asleep. For this reason, melatonin supplements are often used as a natural remedy for insomnia and other sleep disorders. 

How much Melatonin does a supplement contain?

Most melatonin supplements contain between 1 & 10 milligrams (mg) of melatonin. The body naturally produces very small amounts of this hormone under 0.3 mg of melatonin every 24 hours, so taking even a small supplement can increase its levels significantly.

Most over-the-counter melatonin supplements, however, have a much higher dose, usually 1 mg, 3 mg, or 5 mg. That's because the melatonin in supplements is typically synthetic, and our bodies only absorb a small portion of the total dose (around 15%).

While melatonin is found in a variety of foods, the levels are generally quite low. For example, one cup (240 ml) of tart cherry juice has only about 0.3 mg of melatonin. Therefore it's difficult to get enough melatonin from one’s diet alone and supplements may be necessary to raise blood levels significantly. 

What's the recommended dose of Melatonin?

The recommended dose of melatonin varies depending on why you're taking it. For example, the dose for people with insomnia may be different than the dose for people with jet lag. The dose also varies depending on your age. Children often take lower doses than adults. The acceptable dose of melatonin in food supplements as per the latest FSSAI notification is 10 mg per day.

Melatonin dosage is calculated based on weight by some experts. Melatonin can be taken in a dose of 0.04 mg to 0.08 mg per kilogram of body weight per day. For instance:

It is recommended that adults who weigh 155 pounds (70 kg) take 3 mg to 6 mg of melatonin.

A 6-year-old child who weighs 41 pounds can take 0.75 mg to 1.5 mg of melatonin.

The following ranges are recommended for different age groups that may be more practical for calculating dosage:

Children: 0.5 mg to 5 mg

Adults: 0.5 mg to 10 mg

Older adults: 0.1 mg to 5 mg (Melatonin is more difficult to digest after age 55) 

Please note that these ranges are only intended for short-term use. Taking a supplement "short-term" could mean taking it for anywhere from five days to 13 weeks. As the long-term safety of supplements has not been fully researched, it may be best to avoid taking them beyond what your healthcare provider has recommended.

Melatonin Overdose

Melatonin is generally considered to be highly safe. There is no evidence that it causes physical dependence like other sleep aids, and no one has died from melatonin overdose so far.

According to animal experiments, mortality from melatonin overdose is theoretically possible. Rats who showed mortality during experimentation were given 400 mg/kg of melatonin and they experienced respiratory problems. However, this would be 10,000 times the recommended human dosage.

Overdosing of melatonin is a rare phenomenon, but it can happen. Symptoms of overdose include:

• Drowsiness
• Weakness
• Headache
• Nausea or Vomiting
• Diarrhea
• Irritability
• Anxiety
• Rapid Heartbeat
• High Blood Pressure

If you or someone you know has taken too much melatonin, call your local poison control center or emergency room right away.

Melatonin supplementation: Who are at-risk?

In general, melatonin supplementation is likely safe when taken at recommended doses for short-term use. However, some people may be at greater risk of experiencing side effects or adverse reactions to melatonin supplements. These include:

• People with autoimmune conditions: Melatonin may worsen symptoms in people with autoimmune conditions such as Multiple Sclerosis (MS) and Lupus.
• People with bleeding disorders: Melatonin may increase the risk of bleeding in people with conditions such as Haemophilia and Von Willebrand disease.
• People taking blood thinners: Melatonin may interact with medications such as Warfarin and Aspirin, which can increase the risk of bleeding.
• People with diabetes: Melatonin may lower blood sugar levels, which could be a problem for people with diabetes.
• People with high blood pressure: Melatonin may cause a temporary increase in blood pressure.
• Pregnant women: Melatonin is not recommended for pregnant women due to the lack of safety data.
• Nursing mothers: Melatonin is not recommended for nursing mothers due to the lack of safety data.
  

Drug interactions with Melatonin

You should not take melatonin if you are taking any of the following medications:

• Anticoagulants (blood thinners) such as Warfarin (Coumadin)
• Medications for high blood pressure such as Beta-Blockers
• Diabetes medication such as Insulin
• Immunosuppressant drugs such as Cyclosporine (Neoral, Sandimmune)
• Stomach acid-reducing drugs such as Omeprazole (Prilosec)
• Sedatives such as Diazepam (Valium)

Melatonin may also interact with other medications. Be sure to tell your doctor about all the drugs you take, including over-the-counter medications, herbs, and supplements.

Summing Up

Melatonin is a supplement that is generally considered to be safe when taken at recommended doses for short-term use. However, some people may be at greater risk for side effects or adverse reactions. These include people with autoimmune conditions, bleeding disorders, and those taking blood thinners or diabetes medications. Melatonin may also interact with other medications. Pregnant and nursing women should avoid taking melatonin due to the lack of safety data.

Sources

1.   The effectiveness of melatonin for promoting healthy sleep: a rapid evidence assessment of the literature (nih.gov)

Q1. Is it good to take a Melatonin supplement?

It is safe to take Melatonin for 1-2 months, i.e., for short-term use.

Q2. Can Melatonin be taken every night?

Melatonin is generally safe for short-term use, but studies on its long-term effects are limited. The side effects of Melatonin are typically mild. If you take Melatonin and notice that it isn't helping you fall asleep or causes unwanted side effects, stop taking it

Q3. What are the negative effects of Melatonin?

There are very mild side or negative effects of Melatonin, these effects include headache, nausea, dizziness & drowsiness.

Q4. Who should avoid consuming Melatonin?

Melatonin is generally safe when consumed in 0.3-0.5 mg/day. Children and people with Autoimmune disorders should ideally avoid taking them.