Melatonin is a common dietary supplement that has gained widespread popularity around the globe.

Though renowned as a natural sleep aid, it also has powerful effects on other aspects of your health.

This article reviews the benefits and potential side effects of melatonin, as well as its best dosage.

What Is Melatonin?

Melatonin is a hormone produced by the pineal gland in your brain (1Trusted Source).

It’s primarily responsible for regulating your body’s circadian rhythm to manage your natural sleep cycle (2Trusted Source).

Therefore, it’s often used as a sleep aid to combat issues like insomnia.

It’s widely available in the US and Australia as an over-the-counter medication but requires a prescription in other parts of the world, such as Europe.

In addition to improving sleep, melatonin is also involved in managing immune function, blood pressure and cortisol levels (3Trusted Source).

Plus, it acts as an antioxidant, with some research finding that it can significantly affect many health conditions.

In fact, studies show that melatonin may improve eye health, reduce symptoms of seasonal depression and even provide relief from acid reflux (4Trusted Source5Trusted Source6Trusted Source).

Can Support Better Sleep

Melatonin is often called the sleep hormone — and for good reason.

It’s one of the most popular sleep aids and a common natural remedy to treat issues like insomnia.

Multiple studies have demonstrated that melatonin can support better sleep.

One study in 50 people with insomnia showed that taking melatonin two hours before bed helped people fall asleep faster and enhanced overall sleep quality (7Trusted Source).

Another large analysis of 19 studies in children and adults with sleep disorders found that melatonin reduced the amount of time it took to fall asleep, increased total sleep time and improved sleep quality (8Trusted Source).

However, though melatonin is associated with fewer side effects than other sleep medications, it may be less effective (8Trusted Source).

Could Reduce Symptoms of Seasonal Depression

Seasonal affective disorder (SAD), also called seasonal depression, is a common condition that is estimated to affect up to 10% of the population worldwide (9Trusted Source).

This type of depression is related to changes in the seasons and occurs each year around the same time, with symptoms typically appearing in late fall to early winter.

Some research indicates that it could be linked to changes in your circadian rhythm caused by seasonal light changes (10Trusted Source).

Because melatonin plays a role in regulating circadian rhythm, low doses are often used to decrease symptoms of seasonal depression.

According to one study in 68 people, alterations in circadian rhythm were shown to contribute to seasonal depression, but taking melatonin capsules daily was effective at reducing symptoms (5Trusted Source).

However, other research is still inconclusive on the effects of melatonin on seasonal depression.

For instance, another review of eight studies showed that melatonin was not effective at reducing symptoms of mood disorders, including bipolar disorder, depression and SAD (11Trusted Source).

Further research is needed to determine how melatonin may impact symptoms of seasonal depression.

May Increase Levels of Human Growth Hormone

Human growth hormone (HGH) is a type of hormone that is vital to growth and cellular regeneration (12Trusted Source).

Higher levels of this important hormone have also been linked to increases in both strength and muscle mass (13Trusted Source14Trusted Source).

Some studies have found that supplementing with melatonin may increase levels of HGH in men.

One small study in eight men found that both low (0.5 mg) and high (5 mg) doses of melatonin were effective at increasing HGH levels (15Trusted Source).

Another study in 32 men showed similar results (16Trusted Source).

However, larger-scale studies are needed to understand how melatonin may affect levels of HGH in the general population.

Can Promote Eye Health

Melatonin is high in antioxidants that can help prevent cell damage and keep your eyes healthy.

In fact, research suggests that melatonin could be beneficial in treating conditions like glaucoma and age-related macular degeneration (AMD) (17Trusted Source).

In a study in 100 people with AMD, supplementing with 3 mg of melatonin for 6–24 months helped protect the retina, delay age-related damage and preserve visual clarity (4Trusted Source).

Additionally, a rat study found that melatonin decreased the severity and incidence of retinopathy — an eye disease that affects the retina and can result in vision loss (18Trusted Source).

However, research is limited and additional human studies are needed to determine the effects of long-term melatonin supplements on eye health.

May Help Treat GERD

Gastroesophageal reflux disease (GERD) is a condition caused by the backflow of stomach acid into the esophagus, resulting in symptoms like heartburn, nausea and belching (19Trusted Source).

Melatonin has been shown to block the secretion of stomach acids. It also decreases the production of nitric oxide, a compound that relaxes your lower esophageal sphincter, allowing stomach acid to enter your esophagus (20Trusted Source).

For this reason, some research suggests that melatonin may be used to treat heartburn and GERD.

One study in 36 people showed that taking melatonin alone or with omeprazole — a common GERD medication — was effective at relieving heartburn and discomfort (6Trusted Source).

Another study compared the effects of omeprazole and a dietary supplement containing melatonin along with several amino acids, vitamins and plant compounds in 351 people with GERD.

After 40 days of treatment, 100% of people taking the melatonin-containing supplement reported a reduction in symptoms compared to only 65.7% of the group taking omeprazole (20Trusted Source).


Melatonin can be taken in doses of 0.5–10 mg per day.

However, because not all melatonin supplements are the same, it’s best to stick to the recommended dosage on the label to avoid adverse side effects.

You may also want to start with a lower dose and increase as needed to find what works for you.

If you’re using melatonin to improve sleep quality, try taking it 30 minutes before bedtime for maximum effectiveness.

Meanwhile, if you’re using it to correct your circadian rhythm and establish a more regular sleep schedule, you should take it about 2–3 hours before you go to bed.

Safety and Side Effects

Research shows that melatonin is safe and non-addictive for both short- and long-term use in adults (21Trusted Source).

Additionally, despite concerns that supplementing with melatonin may decrease your body’s ability to produce it naturally, several studies show otherwise (22Trusted Source23Trusted Source).

However, because long-term studies on the effects of melatonin are limited to adults, it’s not currently recommended for children or adolescents (24Trusted Source).

Some of the most commonly reported side effects associated with melatonin include nauseaheadaches, dizziness and sleepiness (21Trusted Source).

Melatonin may also interact with certain medications, including antidepressants, blood thinners and blood pressure medications (25Trusted Source2627Trusted Source).

If you’re taking any of these medications, talk to your doctor before taking melatonin to prevent adverse effects.

The Bottom Line

Melatonin may improve sleep, eye health, seasonal depression, HGH levels and GERD.

Doses of 0.5–10 mg per day appear to be effective, though it’s best to follow label recommendations.

Melatonin is safe and associated with minimal side effects, but may interact with some medications. It’s currently not recommended for children.

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