What is melatonin?
Melatonin is a hormone that your body makes naturally .
It’s produced by the pineal gland in your brain but also found in other areas, such as your eyes, bone marrow, and gut .
It’s 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’s nighttime so that you can relax and fall asleep more easily.
Melatonin supplements are popular among people with insomnia and jet lag. You can buy melatonin supplements without a prescription in many countries.
In addition to its benefits for sleep, this hormone has strong antioxidant and anti-inflammatory effects .
How does melatonin work?
Melatonin works in tandem 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
- eat
Melatonin also helps regulate your body temperature, blood pressure, blood glucose, body weight, and levels of some hormones .
Your melatonin levels start to rise when it’s dark outside, signaling to your body that it’s time to sleep. They then decrease in the morning, when it’s light outside, to promote wakefulness .
Melatonin also binds to receptors in your body to help you relax.
For instance, it binds to receptors in your brain to reduce nerve activity. It can also reduce levels of dopamine, a hormone that helps you stay awake, and is involved in some aspects of the day-night cycle of your eyes .
Although melatonin’s exact mechanisms are unclear, research suggests that these processes may help you fall asleep.
Conversely, daylight modulates melatonin production, which is one way your body knows it’s time to wake up .
Because melatonin helps your body prepare for sleep, people who don’t make enough of it at night can have trouble falling asleep.
Many factors may cause low melatonin levels at night, such as alcohol consumption, smoking, caffeine consumption, shift work, aging, certain medications, and exposure to too much light at night — including blue light .
Taking a melatonin supplement may help counter low levels and normalize your internal clock.
Taking melatonin for sleep may help
Strong evidence suggests that taking melatonin before bed decreases sleep latency — the time it takes you to fall asleep — while increasing total sleep time .
A review of 11 studies demonstrated that taking melatonin before bed decreased sleep latency by almost 3 minutes and increased total sleep time by about 30 minutes, compared with a placebo .
Another analysis of 23 studies in people with disease-related sleep disorders found that melatonin significantly reduced sleep disturbances and sleep latency while increasing sleep duration and quality .
Although this analysis concluded that melatonin wasn’t helpful for improving sleep in people with mental disorders or brain diseases such as Alzheimer’s disease, other studies have shown otherwise .
Additionally, melatonin may counteract jet lag, a temporary sleep disorder.
Jet lag occurs when your body’s internal clock is out of sync with a new time zone. Shift workers may also experience jet lag symptoms because they work during hours that are normally used for sleep .
Melatonin may help reduce jet lag by syncing your internal clock with the time change .
For instance, an analysis of 11 studies in people who traveled through 5 or more time zones found that melatonin was likely effective at reducing the effects of jet lag .
Before trying melatonin, though, it’s best to implement healthy sleep habits such as establishing a consistent sleep schedule, limiting alcohol and caffeine consumption, and reducing your exposure to light and electronic devices before bed.
Additional melatonin health benefits
In addition to improving sleep, melatonin may provide other health benefits.
May support eye health
Healthy indole-derived melatonin levels may support eye health.
That’s because this hormone has powerful antioxidant effects that may lower your risk of eye diseases, such as age-related macular degeneration (AMD) .
Indeed, a review concluded that melatonin supplements may reduce AMD by neutralizing free radicals and decreasing inflammation .
May help treat acid reflux and GERD
Melatonin may help alleviate acid reflux and gastroesophageal reflux (GERD) by protecting the lining of your esophagus — the tube that connects your throat and stomach — against irritants such as acid, alcohol, and nonsteroidal anti-inflammatory drugs .
For example, one study showed that taking melatonin inhibits an enzyme system that damages the esophageal epithelial barrier, which is responsible for protecting deeper layers of your esophagus from damage.
Damage to the esophageal epithelial barrier is known to cause acid reflux and GERD and may eventually lead to more severe health complications such as cancer .
Still, further research is necessary.
May reduce symptoms of tinnitus
Tinnitus is a condition characterized by ringing in the ears. It’s often worse when there’s less background noise, such as when you’re trying to fall asleep .
Interestingly, researchers suggest that taking melatonin may help reduce symptoms of significant tinnitus and improve sleep.
A review of five studies concluded that melatonin use alone or alongside tinnitus medications may manage this condition while improving sleep. However, these studies were of low quality, limiting the strength of the review’s findings .
May alleviate migraine attacks
A migraine attack is a recurring type of headache that causes severe, throbbing pain or a pulsing sensation, often on the side of your head.
Several prescription drugs help treat migraine, but melatonin may also offer relief due to its ability to inhibit pain sensations .
In a review of 11 studies, taking melatonin significantly reduced migraine severity and frequency compared with a placebo in both children and adults, but with varying effectiveness .
A different review of 25 studies found similar results, suggesting that taking 3 mg of melatonin at bedtime reduced migraine frequency in adults .
Melatonin side effects
Current evidence suggests that melatonin supplements are safe, nontoxic, and not addictive for either children or adults .
Supplementing long term is also likely safe. Studies have found no significant adverse events associated with daily melatonin intake in dosages of 2–10 mg for up to 3.5 years .
Unlike other hormones, no evidence suggests that taking melatonin affects your body’s natural ability to make its own.
However, several minor, short-lived side effects of melatonin supplements have been reported. These include :
- daytime sleepiness
- fatigue
- dizziness
- headaches
- nausea
- a cold feeling
The bottom line
Melatonin is an effective supplement that may help you fall asleep, especially if you have insomnia or jet lag. It may offer other health benefits as well.
If you’re considering melatonin, it’s important to talk with a doctor or pharmacist first to find out whether it’s right for you and whether it could interact with any medications you’re taking.
Then, you can start with a low dose of 0.5–1 mg 30 minutes before bed. If that doesn’t help, try increasing your dose to 3–5 mg.
Melatonin is generally well tolerated, although mild side effects are possible.
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