Melatonin is a hormone that your body naturally produces. It plays a role in regulating your sleep-wake cycle.

There’s also a lab-made version of melatonin that’s available as an over-the-counter supplement. Some people use melatonin supplements to help with sleep problems like jet lag and insomnia.

In this article we’ll explore how exactly melatonin works and whether it’s safe to take melatonin supplements every night.

Natural melatonin is predominantly made in your pineal gland, which is located in your brain. Light exposure inhibits the production of melatonin, but darkness stimulates it.

Melatonin levels in your brain begin to increase at dusk as the sun goes down and darkness falls. They reach their peak levels in the middle of the night and start decreasing as dawn gets closer.

The action of melatonin inhibits signals in your brain that promote wakefulness. This helps encourage sleep by making you feel tired or drowsy as you get closer to bedtime.

Because of melatonin’s sleep-promoting effects, melatonin supplements are used to treat a variety of sleep problems. These can include:

The Food and Drug Administration (FDA) doesn’t regulate melatonin as a drug. Because of this, there’s limited information on the optimal, safe dosage of melatonin.

In fact, the doses of melatonin supplements that have been used in various scientific studies vary widely, from 0.1 to 10 milligrams (mg). One 2017 review defines a typical dose of melatonin to be between 1 and 5 mg.

Melatonin typically takes 1 to 2 hours to work, so it’s often taken up to 2 hours before bedtime.

If you’re looking to try melatonin for the first time, it may be best to begin with a lower dose. Your doctor can help recommend a safe dose for you to start with.

Melatonin for children

Like melatonin for adults, there’s not much information on the optimal, safe dosage for children. Dosage may also vary depending on a child’s age. One 2016 review suggests the following age-based dosages 30 to 60 minutes before bedtime:

  • 1 mg for infants
  • 2.5 to 3 mg for older children
  • 5 mg for adolescents

Because there aren’t clear dosing guidelines regarding melatonin for children, be sure to speak to your child’s pediatrician before giving melatonin to your child.

Melatonin for older adults

The amount of melatonin your body produces decreases with age. Because of this, melatonin supplements may be helpful for older adults who are having trouble falling asleep.

Researchers are still looking into the optimal melatonin dosage for older adults. One 2016 review of sleep aids for older adults suggests a dosage of 1 to 2 mg of immediate-release melatonin 1 hour before bedtime.

What to know about dietary supplements and safety

The FDA classifies melatonin as a dietary supplement, meaning that it’s regulated less strictly than a regular drug. For dietary supplements, label claims and product safety don’t have to meet FDA approval before they’re marketed.

A 2017 study of 31 different melatonin supplements found that the actual melatonin content of 71 percent of the products didn’t match the claim on the label. Additionally, 26 percent of products contained serotonin, which can be potentially harmful even in small doses.

When shopping for melatonin supplements, look for products that are “USP verified.” United States Pharmacopeia (USP) is an independent organization that works to ensure proper quality and dosing of dietary supplements.

According to the National Center for Complementary and Integrative Health (NCCIH), short-term use of melatonin supplements appears to be safe for most adults and children. However, information on the effects of long-term melatonin supplements is limited.

Some studies have indicated that long-term melatonin use in adults may cause mild side effects when compared to a placebo. Studies into the effects of long-term melatonin use in children remains limited.

Because melatonin levels naturally decrease at the beginning of puberty, there’s some concern that long-term melatonin use in children may delay puberty onset. However, more research is needed.

Melatonin is generally safe. However, mild side effects can sometimes occur, particularly if you take higher doses or extended-release formulations.

The side effects of melatonin can include:

Some less common side effects of melatonin include:

If you experience side effects from melatonin, stop taking it and speak with your doctor. They may recommend using a lower dose or trying out an alternative medication or sleep aid.

You may be wondering what happens if you take a dose of melatonin and find that you still can’t fall asleep. Can you take another dose?

While taking an additional dose is unlikely to cause harm, it may increase your risk for experiencing unwanted side effects.

If you find that melatonin isn’t helping you fall asleep, stop using it. Your doctor may be able to suggest different medications or strategies to help you fall asleep.

There are some important things to know about melatonin, its interactions with other substances, and when it’s best to avoid it. Let’s take a closer look.

What medications and substances does melatonin interact with?

Melatonin may interact with several different types of medications, including:

Because melatonin supplements can make you tired and drowsy, avoid mixing them with:

Are there any people who should avoid taking melatonin?

There’s limited research into the safety of using melatonin supplements during pregnancy. Also, while melatonin is a normal component of breast milk, there’s little research into the effects of taking melatonin supplements while breastfeeding.

Because of this, it’s best to avoid taking melatonin if you’re:

  • pregnant
  • planning to become pregnant
  • breastfeeding

Additionally, it’s important to speak to your doctor before using melatonin if you have:

It’s a good idea to schedule an appointment with your doctor or healthcare provider if you notice that you:

  • frequently have trouble falling asleep or staying asleep at night
  • often feel drowsy or tired during the day
  • have trouble performing your daily activities

Your doctor will work with you to discuss your sleep routine and lifestyle habits. They may also ask you to keep a sleep diary to track the amount of sleep you’re getting over a period of time.

It’s also possible that your doctor will perform a physical exam and order blood tests. These can help them rule out a medical condition that may be causing your sleep issues.

Melatonin supplements can be used to help promote sleep. Because there’s currently no standard dosage associated with melatonin supplements, talk to your doctor about how much melatonin to take and when.

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 and speak with your doctor. They can help recommend other strategies to help you get a good night’s sleep.