How Long Does Melatonin Last For?

If you can't fall asleep and stay asleep at night, you're not alone. Up to 70 million Americans experience a sleep disorder each year, and up to half of American adults experience some symptoms of insomnia (per Cleveland Clinic). One 2010 research review published in Sleep showed that a lack of quality shut-eye, especially over time, is associated with higher rates of mortality. Even one night of sleep loss can harm physical and mental health, according to a 2021 study published in the Annals of Behavioral Medicine.

Among the treatment options for chronic sleep issues, melatonin is one of the most common and easily accessible (via Sleep Foundation). Melatonin is a naturally occurring hormone released in the body in the evening, as the sun goes down. In supplement form, it may help to balance low levels of natural melatonin, making it easier to fall asleep.

However, these supplements may not last all night. Here's how long melatonin actually lasts in your system.

Melatonin supplements may help you fall asleep more easily, but they don't typically last for a full night. According to a 2022 report published on StatPearls, melatonin has a half-life of one to two hours. This means that melatonin can last between four and 10 hours in total (per Medical News Today). However, Healthline suggests that melatonin typically only works for up to five hours before being eliminated from the body. This is less than the seven to nine hours of sleep that the Centers for Disease Control and Prevention recommends for adults.

Some people may find that melatonin's effects last for a different amount of time than the estimates suggest, based on how their body metabolizes the supplement. A number of factors including age, caffeine intake, smoking, body type, and interactions with other medications may impact how long melatonin works. Additionally, dosage and formulation may dictate how effective these supplements are and how long they work (via Healthline).

For some people, the few hours that melatonin lasts in the body are more than enough. This is especially true for those who sleep fewer than the recommended number of hours per night. But for others, melatonin may not last long enough to keep them snoozing soundly until the morning. A few small adjustments might make melatonin last longer each night.

First, it's critical to choose the right type of melatonin supplement. If melatonin seems to wear off too quickly, it's best to opt for an extended-release formulation rather than an immediate-release tablet, writes Medical News Today. Extended-release supplements are made to release gradually into the bloodstream, lasting several hours.

It's also critical to avoid taking melatonin too early. These supplements usually kick in within one hour and should be taken shortly before bedtime. According to Healthline, people taking melatonin for the first time should take it 30 minutes before they want to sleep and adjust later as needed.

There are also lifestyle habits that can boost the effectiveness of melatonin supplements. Light can interfere with melatonin, so it's best to dim room lamps and banish bright screens from the bedroom (per WebMD). The Sleep Foundation also points out that caffeine can diminish melatonin production, so even when taking melatonin supplements, avoiding caffeinated beverages late in the day could make it easier to stay asleep at night.