How much melatonin is too much?

Key takeaways

• While melatonin is generally safe, exceeding the recommended maximum dose of 10 milligrams (mg) may lead to side effects like headaches and fatigue.
• The appropriate melatonin dosage varies based on individual needs, with 2 mg recommended for short-term insomnia and up to 10 mg for long-term sleep issues.
• Consulting a doctor before taking melatonin is crucial, especially if you’re on other medications, to avoid potential harmful interactions.

Overview

Melatonin is a naturally occurring hormone your body makes to help you fall asleep. Your brain triggers the release of melatonin in response to darkness, which helps regulate your circadian rhythm. This is the internal 24-hour body clock that indicates your sleep and wake cycle.

Melatonin is available over the counter as a dietary supplement in the form of tablets, liquids, or patches. They typically contain synthetic melatonin but may contain alternatives from animals or microorganisms.

The ideal dosage of melatonin will vary depending on your specific needs and what your body can tolerate.

While melatonin supplements are safe and come with minimal risks, overdosing on these supplements can cause serious side effects. It’s important to know how much you should be taking to avoid unpleasant symptoms.

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Is 20 mg of melatonin too much?

Melatonin capsules can come in many different strengths, including:

• 2 milligrams (mg)
• 5 mg
• 10 mg

This allows you to take small doses first to see whether you can tolerate it before moving on to higher doses.

Certain factors will affect your tolerance to melatonin supplements, such as:

• your weight
• age
• your general physiological sensitivity

Lower doses of between 0.5 and 5 mg are typically effective enough for sleep conditions like jet lag, delayed sleep–wake phase disorder, and insomnia in elderly patients. The usual maximum dose of melatonin is 10 mg once daily.

Depending on your reason for taking melatonin, a doctor may recommend taking these supplements only 2 to 3 times per week to see whether it has a positive effect.

A very small review study suggests that high dose melatonin, defined as doses equal to or higher than 10 mg, may increase the risk of side effects like headaches, dizziness, and drowsiness.

Melatonin supplements are safe, but healthcare professionals don’t typically advise taking 20 mg at once.

What is the recommended dosage of melatonin for sleep?

If you’re an adult with difficulty sleeping or a health condition that prevents you from getting good-quality sleep, a doctor may advise melatonin supplementation.

Melatonin supplements are slow-release, meaning they gradually take effect during the night. It’s best to take melatonin with food. If your supplements are slow-release, do not crush or cut them up.

The recommended dose for short-term insomnia in adults is 2 mg, to take 1 to 2 hours before you go to bed. This dosage typically has an immediate release.

Doctors don’t recommend taking melatonin for more than 4 weeks when experiencing short-term sleep problems.If you’re still experiencing symptoms after this time, consider speaking with a healthcare professional.

For long-term insomnia, doses may increase to 10 mg per day, to be taken 30 minutes to 1 hour before you go to bed.

If you’re taking melatonin to help ease jet lag, you can’t take it for longer than 5 days.

You can also take melatonin when flying to avoid jet lag symptoms. The recommended doses are 0.5 mg to 2 mg to be taken preflight and 5 mg postflight for up to 4 days.

Side effects of taking too much melatonin

Melatonin is a very safe supplement that is not known to be life threatening, even at doses as high as 800 mg. But taking more than a doctor recommends can result in side effects such as:

• drowsiness and fatigue
• changes to your eyesight
• feeling faint
• unexplained blood in urine
• urinary incontinence
• nightmares
• dizziness and confusion
• headaches
• low blood pressure
• hypothermia
• rapid heart rate

What should you not take with melatonin?

Before taking melatonin supplements, it’s important to speak with a doctor to help you understand what you should do. This is especially important if you’re taking other medications.

Melatonin can affect how certain medications work or cause dangerous side effects when interacting with these substances.

These medications include:

• Benzodiazepines: Taking melatonin alongside benzodiazepines, such as diazepam (Valium), can increase your risk of melatonin overdose and increase the sedative effects of the benzodiazepine drug.
• Zolpidem (Ambien): Zolpidem is a medication that can help relieve insomnia. Taking melatonin at the same time can cause extreme drowsiness and increase your risk of strong side effects.
• Warfarin (Coumadin): There is some evidence that melatonin can increase the action of warfarin and cause excess blood thinning. This may increase your chance of life threatening bleeding.
• Nonsteroidal anti-inflammatory drugs (NSAIDs): NSAIDs can reduce the activity of melatonin, so be careful when taking medications like ibuprofen (Advil) with melatonin, as it may lower the effectiveness of the supplement.
• Birth control pills: Taking melatonin at the same time as birth control, such as levonorgestrel and ethinyl estradiol (Tyblume), may increase your likelihood of experiencing melatonin side effects like extreme drowsiness.
• Antihistamines: First-generation antihistamines are sedatives that often cause drowsiness. Taking melatonin at the same time as one of these medications, like diphenhydramine (Benadryl), can increase your chance of side effects like extreme fatigue.

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Summary

A 20-mg dose of melatonin is above the standard recommended amount and may cause side effects like severe fatigue. The typically recommended dosage is up to 10 mg.

If you want to try melatonin for symptoms such as insomnia, it’s important to speak with a doctor first.

This is to ensure you’re not at risk of any harmful drug interactions, as other medications can increase the side effects of melatonin.  

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