Although it is a common problem, poor sleep can have severe consequences.

Poor sleep can deplete your energy, lower your productivity and increase the risk of diseases like high blood pressure and diabetes (1).

Melatonin is a hormone that tells your body when it is time to head to bed. It has also become a popular supplement among people struggling to fall asleep.

This article explains how melatonin works, as well as its safety and how much to take.

Melatonin is a hormone made naturally by your body.

It is produced by the pineal gland in the brain but also found in other areas, such as the eyes, bone marrow and gut (2, 3).

It is often called the “sleep hormone,” as high levels can help you fall asleep.

However, melatonin itself won’t knock you out. It simply lets your body know that it is night-time so you can relax and fall asleep easier (4).

Melatonin supplements are popular among people struggling with insomnia and jet lag. You can get it in many countries without a prescription.

Melatonin is also a powerful antioxidant, which may provide a variety of other benefits.

In fact, it may help support eye health, treat stomach ulcers and heartburn, ease tinnitus symptoms and even raise growth hormone levels in men.

SUMMARY:Melatonin is a hormone that is naturally made by the pineal gland. It helps you fall asleep by calming the body before bed.

Melatonin works together with your body’s circadian rhythm.

In simple terms, the circadian rhythm is your body’s internal clock. It lets you know when it’s time to sleep, wake and eat.

Melatonin also helps regulate your body temperature, blood pressure and hormone levels (5, 6).

Melatonin levels start to rise in your body when it is dark outside, signaling to your body that it is time to sleep (7).

It also binds to receptors in the body and can help you relax. For instance, melatonin binds to receptors in the brain to help reduce nerve activity. In the eyes, it can help reduce dopamine levels, a hormone that helps you stay awake

Although the exact way melatonin helps you fall asleep is unclear, research suggests these processes can help you fall asleep.

Conversely, light suppresses melatonin production. This is one way that your body knows it is time to wake up (11).

As melatonin helps your body prepare for sleep, people who don’t make enough of it at night can struggle to fall asleep.

There are many factors that may cause low levels at night. Stress, smoking, exposure to too much light at night (including blue light), not getting enough natural light during the day, shift work and aging all affect melatonin production

Taking a melatonin supplement may help counter low levels and normalize your internal clock.

SUMMARY:Melatonin works closely with your body’s circadian rhythm to help prepare you for sleep. Its levels rise at night-time.

Evidence shows that taking melatonin before bed can help you get to sleep

In an analysis of 19 studies on people with sleep disorders, scientists found that melatonin helped reduce the time it took to fall asleep by an average of 7 minutes.

In many of these studies, people also reported significantly better quality of sleep

Additionally, melatonin can help with jet lag, a temporary sleep disorder.

Jet lag occurs when your body’s internal clock is out of sync with the new time zone. Shift workers may also experience jet lag symptoms since they work during a time normally saved for sleep (20).

Melatonin can help reduce jet lag by syncing your internal clock with the time change (21).

For instance, an analysis of 10 studies explored the effects of melatonin in people who traveled through five or more time zones. Scientists found that melatonin was remarkably effective at reducing the effects of jet lag.

The analysis also found that both lower doses (0.5 mg) and higher doses (5 mg) were equally effective at reducing jet lag (22).

SUMMARY:Evidence shows that melatonin can help you fall asleep faster. In addition, it can help people with jet lag get to sleep.

Taking melatonin may provide you with other health benefits as well.

May Support Eye Health

Healthy melatonin levels may support eye health.

It has powerful antioxidant benefits that could help lower the risk of eye diseases, such as age-related macular degeneration (AMD) (23).

In one study, scientists asked 100 people with AMD to take 3 mg of melatonin over 6 to 24 months. Taking melatonin daily helped protect the retinas and delay damage from AMD, without any significant side effects (24).

May Help Treat Stomach Ulcers and Heartburn

The antioxidant properties of melatonin may help treat stomach ulcers and alleviate heartburn (25, 26, 27).

A study with 21 participants found that taking melatonin and tryptophan along with omeprazole — a common medication for acid reflux — helped heal stomach ulcers caused by the bacteria H. pylori faster (28).

In another study, 36 people with gastroesophageal reflux disease (GERD) were given either melatonin, omeprazole (a medicine that helps treat GERD) or a combination of both to treat GERD and its symptoms.

Melatonin helped reduce heartburn and was even more effective when combined with omeprazole (29).

However, this area of research is fairly new. Future studies will help clarify how effective melatonin is in treating stomach ulcers and heartburn.

May Reduce Symptoms of Tinnitus

Tinnitus is a condition characterized by a constant ringing in the ears. It is often worse when there is less background noise, such as when you’re trying to fall asleep.

Interestingly, taking melatonin may help reduce symptoms of tinnitus and help you get to sleep (30, 31, 32).

In one study, 61 adults with tinnitus took 3 mg of melatonin before bed for 30 days. It helped reduce the effects of tinnitus and significantly improved sleep quality (32).

May Help Increase Growth Hormone Levels in Men

Human growth hormone is naturally released during sleep. In healthy young men, taking melatonin may help increase growth hormone levels.

Studies have shown that melatonin can make the pituitary gland, the organ that releases growth hormone, more sensitive to the hormone that releases growth hormone (33, 34).

In addition, studies have shown that both lower (0.5 mg) and higher (5.0 mg) melatonin doses are effective at stimulating growth hormone release (34).

May Help With Seasonal Depression

Seasonal depression is commonly known as the “winter blues” or seasonal affective disorder (SAD). It may affect up to 20% of adults in the US (35).

Some evidence shows that seasonal depression is affected by changes in light and sleep cycles (36).

In turn, melatonin could possibly help reduce symptoms of seasonal depression by helping with the sleep cycle (37, 38).

However, the evidence is not entirely clear. Future studies will help clarify if melatonin could be useful for treating seasonal depression.

SUMMARY:Melatonin may support eye health, ease tinnitus symptoms, treat stomach ulcers and heartburn, increase growth hormone levels in young men and help with seasonal depression.

If you would like to try melatonin, start with a lower dose supplement.

For instance, start with 0.5 mg (500 mcg) or 1 mg 30 minutes before going to bed. If that doesn’t seem to help you fall asleep, try increasing your dose to 3–5 mg.

Taking more melatonin than this likely won’t help you fall asleep faster. The goal is to find the lowest dose that will help you fall asleep.

However, it is best to follow the instructions that come with your supplement.

Melatonin is widely available in the US. You will need a prescription for melatonin in other places, such as Canada, Australia and the UK.