How Long Does Melatonin Last?

A woman holding a melatonin pill and an alarm clock.

Every living entity on Earth has a circadian rhythm, a 24-hour internal cycle that responds to light, dark and different phases of each day. For humans, one of the hormones that is involved in our circadian rhythm is melatonin. Our bodies make melatonin when we are exposed to darkness, but due to irregularities in sleep or other health issues, some people use melatonin supplements to regulate their melatonin levels and circadian rhythm. How long does melatonin last? Learn more about melatonin and how long it stays in the body.

What Is Melatonin?

As stated, melatonin is a hormone that is used to help regulate sleep and the circadian rhythm. It is produced by the pineal gland in the brain and when it is released in the body, it makes you feel tired, ready to go to sleep. Light absorbed by the eye triggers nerve cells to send messages to the brain and pineal gland to stop making melatonin. This helps keep you awake and alert during the day. When darkness arrives, the pineal gland begins producing melatonin again to help you relax and sleep.

The problem with melatonin production and the normal human circadian rhythm is that not everyone needs to sleep on this schedule. Some people work at night or different shifts. Traveling across time zones can interrupt sleep cycles. The body may not make melatonin at the right time to help you relax and sleep in a natural cycle. For many people, melatonin supplements can be the solution to help regulate their circadian rhythm and sleep cycle, as well as derive other health benefits from these supplements.

Melatonin Supplements

Melatonin is available as a supplement – it is not a drug, but sold as a natural supplement like vitamins, minerals or herbs. You will find supplements in doses from 1-5 mg and in a variety of forms. Immediate release tablets will quickly enter your system – some are sublingual, which means they can be absorbed directly into the bloodstream when melted under the tongue. These can make you feel sleepy and relaxed very quickly, but they are not designed to stay in the system for a long time.

Melatonin also can be bought in extended release or time release form. These supplements enter the system more slowly and release the melatonin over time, more like how the pineal gland naturally releases melatonin in the body at night. This can help people stay relaxed longer and sleep better. The dosage you take, the form of release and other factors can affect how long melatonin lasts in your system.

How Long Does Melatonin Stay in Your System?

Melatonin begins to leave the body soon after its released. Within an hour, half of the melatonin released is eliminated. Depending on a variety of factors, melatonin is reduced by half about every 40-60 minutes until it is gone from your system. How long does melatonin stay in your system? Factors like the dose, release-type, age, body weight, caffeine/nicotine intake and overall health can affect how long melatonin lasts.

For many people, melatonin can stay in the system for about five hours. It may be longer if it is a time or extended-release supplement. Since melatonin can make you feel drowsy, it is usually not recommended to drive or operate machinery within five hours of taking a melatonin supplement.

When Should You Take Melatonin?

Since melatonin only lasts for less than an hour before it dissipates by half, you should take melatonin immediately before you want to feel the effects. If you are taking melatonin to help you go to sleep, you should take it within a half an hour of bedtime. Beginners should start with a very low dose to see how it effects your body. Since everyone may metabolize melatonin differently, a lower dose (1 mg) is recommended to begin. High doses can stay in the system longer and may result in a lingering drowsy feeling in the morning.
An Asian woman taking a melatonin pill before going to sleep.
While melatonin is considered a safe supplement, it can be overused. If you take too much or take it too often, it can interrupt your circadian rhythm and negatively affect your sleep patterns. Since most people take melatonin to get better sleep, it is counterproductive to take too much and cause sleep disruptions. Keep in mind that most melatonin supplements will last about five hours, possibly longer if you take larger doses or time-released supplements.

Melatonin can be used to help balance your natural circadian rhythm if you work odd hours or travel frequently. If you wondered, “How long does melatonin last?” you now know how long to expect melatonin to stay in your system. To find out if melatonin is right for you, talk to your doctor and learn more about the right dosage and supplement type to get the results you desire.