How many 10mg melatonin is too much?

Melatonin is a popular over-the-counter sleep aid that many people take to help fall asleep faster and get better quality sleep. It is generally considered safe when taken as directed, but there are some risks with taking too much melatonin. This article will provide a comprehensive overview of melatonin, including how it works, dosage recommendations, potential side effects, and when you may have taken too much.

What is Melatonin?

Melatonin is a hormone produced naturally by the body to regulate sleep-wake cycles. It is secreted by the pineal gland, a small gland located in the brain, in response to darkness to induce sleepiness. Melatonin production increases in the evening as it gets darker outside, making you feel sleepy, and decreases in the morning when it becomes lighter, signaling your body to wake up.

In addition to controlling sleep cycles, melatonin also exerts other effects in the body. It acts as a powerful antioxidant, can enhance immune function, and may have anti-cancer properties. Given its role in regulating circadian rhythms, it has been referred to as the “hormone of darkness.”

Melatonin supplements are synthetically-produced versions of the hormone available as over-the-counter capsules, tablets, liquids, and sublingual preparations. Since melatonin is a hormone, supplements are not regulated as strictly as pharmaceutical drugs. Melatonin supplements can be purchased without a prescription at pharmacies, health food stores, and online.

How Does Melatonin Work?

When taken as a supplement, the melatonin is absorbed into your bloodstream. It then binds to melatonin receptors located throughout the body, particularly in the brain. Binding to these receptors induces drowsiness and promotes sleep.

Specifically, melatonin works by:

  • Signaling to the body’s internal clock that it is nighttime
  • Decreasing core body temperature
  • Altering sleep circuitry by inhibiting wake-promoting signals
  • Increasing overall sleepiness and lethargy

Through these mechanisms, exogenous melatonin from supplements can shorten the time it takes to fall asleep, called sleep latency, increase overall sleep amounts, and improve sleep quality. It does not act as a sedative, but rather mimics the natural sleep-inducing processes.

Melatonin Dosage Recommendations

For treating occasional insomnia or jet lag, the typical adult dosage of melatonin supplements ranges from 0.5 mg to 5 mg taken 30 minutes before bedtime. However, there is no universally agreed upon optimal dose.

Lower doses around 0.5-3 mg are likely sufficient for many people. Higher doses above 5 mg do not necessarily increase effectiveness. Taking more melatonin than your body needs may induce hypnotic, sedative-like effects.

Many melatonin supplements are available in much higher doses, even up to 10 mg per pill or more. However, these higher doses are not necessarily recommended or even beneficial.

The correct dosage can vary by individual based on factors like age, reason for use, other medications, and more. Older adults and children may be more sensitive to melatonin’s effects and should start with smaller doses around 0.5-1 mg.

When using melatonin for the first time, it is advisable to start low at 0.5-1 mg and increase slowly as needed. Never exceed 10 mg per dose.

General Dosage Recommendations Based on Age

  • Adults: 0.5-5 mg
  • Older adults: 0.5-2 mg
  • Children: 0.5-1 mg

Is it Safe to Take 10 mg of Melatonin?

While a 10 mg melatonin pill may be readily available over the counter, taking this entire dose all at once is likely excessive for most people. There are several reasons it is usually not advisable to take 10 mg of melatonin at one time:

  • The required dosage for melatonin is highly individualized and often much lower than 10 mg.
  • Higher doses do not necessarily increase effectiveness and may cause overly drowsy side effects.
  • Your body cannot process such a large dose all at once.
  • High doses could alter natural melatonin production and sleep cycles.

For these reasons, a 10 mg melatonin supplement is considered a high dose that may result in adverse side effects or disruptions to your natural melatonin production. Most experts recommend not exceeding 5 mg for adults. Children and older adults should stay well below 5 mg.

However, there are some exceptions where a healthcare provider may recommend higher short-term doses around 10 mg. This includes people with severe circadian rhythm disorders or who are completely melatonin-deficient.

In these cases, prolonged release forms are preferably used to slowly deliver the higher dose. But for general insomnia, 10 mg taken all at once is usually excessive.

Signs You’ve Taken Too Much Melatonin

Since the optimal melatonin dose varies significantly between individuals, it is possible to unintentionally take too much. Excessive melatonin can result in side effects that disrupt normal functioning.

Here are some signs that may indicate you have taken too much melatonin:

  • Excessive daytime drowsiness: While melatonin will make you fall asleep faster, too high of a dose may leave you feeling drowsy, sluggish, or “hungover” the next day. This impairs concentration, cognition, and ability to perform daily activities.
  • Vivid dreams or nightmares: High melatonin doses can lead to extremely vivid, strange, or frightening dreams and nightmares. You may also have trouble sleeping through the night.
  • Nausea: Some people experience mild nausea, stomach cramps, or digestive upset from too much melatonin.
  • Headaches: Headaches are possible the morning after taking a high amount of melatonin. They are likely caused by drowsiness or impaired sleep quality.
  • Hypnotic state: Significant daytime drowsiness resembling a sedated, hypnotic state may occur after taking too much melatonin.

Pay close attention to these signs of excessive melatonin dosage. If you experience these side effects, reduce your dosage accordingly.

Special Considerations


Melatonin appears to be safe for children when taken short-term and with appropriate pediatrician guidance. However, high doses around 10 mg are never suitable for kids.

Due to their smaller body size, children should always start with the lowest dose possible, generally 0.5-1 mg. Melatonin may affect puberty and development, so it is not recommended for prolonged use in children.

Pregnancy and Breastfeeding

Melatonin supplements likely pose minimal risks during pregnancy, but data is limited. High doses are not recommended. Melatonin does cross into breastmilk, so breastfeeding mothers should consult their doctor before using it.

Underlying Health Conditions

People with certain health disorders like diabetes, depression, and autoimmune conditions have altered melatonin metabolism. High doses may be even more likely to cause adverse effects.

Those on blood thinners or sedatives should use extra caution with melatonin due to possible drug interactions potentiating sedation.

Long-Term Effects of High Doses

While generally recognized as safe for short-term use, high doses of melatonin over months or years may have some long-term consequences.

Potential long-term effects of too much melatonin include:

  • Disruption of reproductive hormone production and fertility
  • Increased risk of headaches
  • Development of autoimmune antibodies
  • Decreased efficacy over time requiring higher doses
  • Altered circadian rhythms and impaired sleep cycles

However, data on the long-term impact of exogenous melatonin is limited at this time.

How to Avoid Negative Effects

You can take several precautions to avoid potential side effects and dangers from taking too much melatonin:

  • Always start with the lowest dose around 0.5 mg and slowly increase as needed
  • Do not exceed 5 mg for adults, 2 mg for older adults, or 1 mg for children
  • Use regular or fast-release forms instead of extended-release
  • Take melatonin 30-60 minutes before bedtime, not earlier
  • Do not drive or operate heavy machinery after taking melatonin
  • Consider stopping melatonin after 3-4 months of use
  • Talk to your doctor about optimal dosing based on your age, medical history, medications, etc.

Following dosage directions carefully and using the smallest effective amount can help minimize any issues.


Melatonin is generally considered safe when used to treat occasional sleep issues. However, taking too much melatonin can disrupt your natural sleep cycle and production of the hormone.

While melatonin supplements are available in doses up to 10 mg or higher, taking this amount all at once may lead to excessive sedation. The recommended dosage for adults ranges from 0.5-5 mg, with lower doses suggested for older adults and children.

Signs of melatonin overdose include next-day drowsiness, vivid dreams, nausea, and headaches. High doses over months or years may also have long-term effects on fertility, immunity, and hormones.

To avoid negative side effects, always start with the lowest dose around 0.5 mg and increase slowly as needed. Do not exceed 10 mg per dose. Melatonin can help improve your sleep when taken as directed, but too much can be counterproductive.

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