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Is Taking Melatonin Bad for You?

If you occasionally or regularly struggle to sleep, melatonin supplements may be on your radar. They are among the most well-known natural sleep aids in the United States, and the amount of people using melatonin has continued to grow1 over the last 20 years. 

However, it can only take a few minutes of searching online to start getting conflicting messages about melatonin. Some people claim it’s bad for you; others say it has saved their sleep. 

In this article, we’ll clear up some of the confusion. With the latest scientific research, we’ll discuss what melatonin is, when you should take it, who should avoid it, the possible side effects and interactions, and the different types of melatonin. We’ll also go over some more general sleep tips that you can implement, whether or not you decide to take melatonin. 

What Is Melatonin?

Melatonin is a hormone that we produce in our pineal gland2. The pineal gland is a small, pea-sized gland located in the brain that senses when it is dark or light outside. When it is dark, the pineal gland begins producing melatonin to help promote sleep.2 

This process is a part of our body’s circadian rhythms, which are all the physical, mental, and behavioral changes3 that follow a 24-hour cycle within our bodies in response to light and dark. One prime example of this is sleeping at night. 

Conversely, once it gets light again in the morning, our melatonin production decreases to help us feel more alert.2 Because of this, melatonin is often referred to as the “sleep hormone.”

For those who struggle with sleep, melatonin supplements may help by increasing the amount of melatonin in your body at night to help support this natural sleep process. Melatonin supplements can be animal-derived, but more often, are made from melatonin synthesized in a lab.2 

When Should You Take Melatonin?

According to the American Academy of Sleep Medicine4 (AASM), melatonin is the most effective at treating circadian rhythm sleep disorders. These include jet lag, shift work, and sleep-wake phase disorders.4 

Jet Lag

Jet lag happens when you travel to a new time zone that isn’t in alignment with your body’s natural circadian rhythms, and research shows that taking melatonin supplements can reduce the effects of jet lag by up to 50 percent if taken correctly.2 

Doctors recommend taking melatonin about two hours5 before your intended bedtime, beginning several days before your trip. 

Shift Work

Shift workers must stay awake through the night when their body’s melatonin levels are naturally rising and alertness is dissipating. Then, they’ll need to sleep once the sun is coming up, and their melatonin levels are falling. This means that shift workers have to go against their body’s natural circadian rhythm. 

According to the AASM, shift workers should take melatonin after the end of their shift, before their intended (morning) bedtime.4 If you must sleep during the day, we’d also strongly recommend blackout curtains, since light impedes the production of melatonin.2 

Sleep-Wake Phase Disorders

There are a few types of sleep-wake phase disorders: delayed sleep-wake phase, advanced sleep-wake phase, and free-running (or non-24-hour) sleep-wake rhythm disorder.4

People with delayed sleep-wake phase disorder naturally go to bed very late and wake up very late. This is when the timing of the circadian rhythm is delayed by at least two hours. Taking melatonin one to two hours before your desired bedtime may help you shift your sleep schedule earlier.4 

People with advanced sleep-wake phase disorder go to bed very early and wake up very early. 

This sleep disorder can be treated by prolonging your light exposure6 at night and then taking melatonin one to two hours before your desired bedtime. 

Finally, free-running/non-24-hour sleep-wake rhythm disorder is a sleep disorder more common in the totally blind population7. Research shows that taking melatonin one or two hours before the desired bedtime can help regulate the circadian rhythms of people who cannot otherwise sense darkness.7


The AASM does not recommend melatonin8 as the best treatment option for chronic insomnia. They define chronic insomnia as difficulty sleeping at least three times a week, with a negative impact on your day-to-day life, for the past three months. While melatonin may help you sleep if you have occasional insomnia, the AASM recommends cognitive behavioral therapy for insomnia (CBT-I) for more chronic insomnia.8

Neurodevelopmental Disorders

Research shows that melatonin supplements can help treat sleep issues9 in children with autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADD/ADHD). While it is generally not recommended long term for children, melatonin may be beneficial for those with neurodevelopmental disorders to take it longer term for sleep.9

Talk to your pediatrician if you believe your child would benefit from taking melatonin. 

When to Be Cautious about Taking Melatonin

According to the National Health Service10 (NHS), melatonin appears to be safe and should have limited side effects for most adults with either short- or long-term sleep problems. However, the NHS says certain populations should avoid melatonin supplements entirely.

  • Those with an allergy – If you have ever had an allergic reaction to melatonin, — or any other medication — the NHS recommends avoiding melatonin supplements.
  • People with autoimmune conditions – If you have rheumatoid arthritis, lupus, multiple sclerosis, or any other autoimmune conditions, you should avoid melatonin as it may stimulate inflammation.
  • Liver and kidney patients – The NHS cautions against taking melatonin for those with liver or kidney problems.

If you’re interested in melatonin supplements and you fall into one of these categories, speak to your doctor first and follow their guidelines. 

  • Pregnant people – While melatonin supplements seem to be safe11 for both parent and baby, you should still talk to your doctor about taking melatonin while pregnant or breastfeeding. 

Learn more: Can You Take Melatonin While Pregnant? 

  • Children – Melatonin is generally considered safe12 for children over three, if used short-term, at the appropriate dose, and in addition to behavioral and lifestyle changes. That said, always talk to your pediatrician before introducing any new supplements into your child’s routine. 

Learn more: A Guide to Melatonin for Kids

  • People taking certain medications – Certain medications13 — including antidepressants, benzodiazepines, blood pressure medications, and more —  may interact with melatonin. You should always speak to your healthcare provider first so they can provide more specific guidance on whether it’s safe for you to take melatonin while on medication.

Are There Side Effects of Taking Melatonin?

Like most supplements or medications, some people can experience side effects when taking melatonin. While the NHS says this is rare14, these are the most common side effects they list: 

  • Daytime tiredness
  • Headache
  • Stomach ache
  • Nausea
  • Dizziness
  • Irritability or restlessness
  • Dry mouth
  • Dry or itchy skin
  • Pains in the arms or legs
  • Strange dreams
  • Night sweats

Research also suggests that melatonin may lower testosterone levels 15 in males, and inhibit male adolescent development16. 

Additionally, it may cause gynecomastia17, which is breast enlargement in males, and melatonin may also affect fertility18 in women.  

If you experience any of these side effects, try lowering your dose, keeping in mind most experts recommend a dose somewhere between 1 and 3 milligrams only.5 

If melatonin simply isn’t working for you, you can stop using it. All side effects should dissipate when you stop taking melatonin.

Does Melatonin Interact with Other Medications?

Melatonin may interact with other medications. Sometimes this means that the melatonin will make the other medication less effective, and sometimes it means the other medication will impact melatonin’s effects. Either way, you should tell your doctor if you’re taking any of these medications before starting melatonin supplements.13 

  • Antidepressants
  • Blood pressure medications
  • Benzodiazepines15
  • Nonsteroidal anti-inflammatory drugs (NSAIDs)
  • Opiates
  • Oestrogens/Estrogens (contained in hormonal birth control and HRT)
  • Psoralens (a psoriasis medication)
  • Carbamazepine (for epilepsy)
  • Quinolones or Rifampicin (specific types of antibiotics)
  • Cimetidine (for stomach ulcers)
  • Thioridazine (a schizophrenia medication)
  • Zaleplon, zolpidem, or zopiclone (an insomnia medication)
  • Warfarin (a medicine to prevent blood clots)

Types of Melatonin

You can buy melatonin in various forms, including fast-release pills, extended-release pills, gummies, melts, liquids, patches, and nasal sprays. Each one is slightly different in its purpose and effect.

Fast-Release Pills

Most melatonin supplements that don’t indicate otherwise are fast- or immediate-release pills19. These can either be tablets or capsules and will release all of the melatonin into your system at once. Fast-release melatonin will likely only help you fall asleep, as there is little evidence to show that it’ll prevent you from waking up during the night. 

Extended-Release Pills 

Extended-release pills are designed to release the active ingredient into the system gradually, rather than all at once.19 With melatonin supplements, this means the melatonin will be released more slowly throughout the night, rather than just at the beginning of the night.  

Though studies are limited, experts believe extended-release melatonin supplements may help you not only fall asleep but stay asleep20 as well.


Melatonin gummies have the benefit of being chewable and sweet-tasting, which can be a plus if you’re giving your child melatonin or you don’t swallow pills well. Since these can seem like candy, you must keep melatonin gummies out of reach of children, who might accidentally eat too many and experience unwanted side effects. 


Melts are specifically designed to melt in the mouth, usually under the tongue or between the gums and the cheek. These quick-dissolve tablets can be beneficial because research suggests you can feel the effects sooner21 and they have higher bioavailability, which means more of the melatonin in the melt will make it into your system.

Liquid Melatonin 

Liquid melatonin is something that you can drink or drop onto your tongue from a dropper. It might be a good fit for you if you have trouble swallowing pills, and it is more child-friendly. 

That said, liquid melatonin will also likely contain sweeteners, which some people may not prefer.


Melatonin patches are patches you place on your body that deliver melatonin through the skin and into your circulatory system22. According to research, they absorb more slowly23, which could be beneficial for those struggling to stay asleep.

Nasal Sprays

Like transdermal patches, nasal sprays have the benefit of avoiding the digestive system, where some melatonin is lost before making its way into the system. Research shows that melatonin nasal sprays take effect faster than any other form of melatonin and also have the highest bioavailability (more melatonin in your system).23 These could be a great option for those who can’t swallow pills well.

More Tips for Better Sleep

Whether you decide to take supplemental melatonin or not, you should also practice good sleep hygiene, which are daily habits that can influence how well you sleep. 

  • Stick to a consistent sleep schedule – If you’re having trouble sleeping, we recommend being strict about your sleep schedule. Go to bed and wake up at the same time each day (including weekends), which can help train your body to feel sleepy and alert at the appropriate times. 
  • Implement a bedtime routine – Establish a relaxing nightly routine for yourself. This can help you wind down from the day to prepare you for sleep. Your routine might include a hot bath or shower, reading, meditating, or doing some gentle stretching. 
  • Make your bedroom conducive to sleep – Your bedroom should be completely dark, a comfortable temperature, and quiet. We also recommend making sure you have the best mattress for your body type and sleep style to help you feel as comfortable as possible.
  • Avoid naps – If you’re having trouble sleeping, a long afternoon nap is probably not helping you. If you must nap, we recommend limiting it to a 30-minute nap (or less) as early in the day as possible. 
  • Increase your melatonin naturally – You don’t need supplements to increase your melatonin; you can do this naturally.  Dim the lights at night to help facilitate melatonin production. Also, put away your screen devices, like smartphones and computers, ideally an hour or two before bedtime. The problem with these tech devices is that they emit a blue light that can suppress melatonin production24. You can also eat more melatonin-rich foods25 eggs, fish, nuts, seeds, legumes, mushrooms, and certain cereals.
  • Limit alcohol and caffeine – While caffeine is widely known for making us feel alert, which is clearly unhelpful for sleep, alcohol can also make sleep worse. Experts say alcohol can lead to more disrupted rest26.
  • Get plenty of exercise – To improve your sleep, you should be getting at least 30 minutes27 of moderate-intensity exercise per day.
  • Don’t eat a big meal before bed – Experts recommend eating dinner at least three hours28 before bedtime so your digestion won’t interfere with your sleep. If you’re hungry right before bed, try a light snack that doesn’t include sugar, high fat, caffeine, or processed ingredients.
  • Try other supplements – If melatonin isn’t a good fit for you, there are other natural sleep aids available to you, including magnesium, valerian root, chamomile tea, and more. However, as with melatonin, contact your healthcare provider before trying any of these supplements.

Check out our guide: Natural Sleep Aids

Frequently Asked Questions

Can taking melatonin every night be harmful?

Generally, doctors do not recommend taking melatonin for more than 13 weeks29 for adults and three weeks for kids30, simply because there is not currently enough research. 

There is some research31 to suggest long-term melatonin use could benefit certain populations of people, such as those with autism spectrum disorder.

Since melatonin can increase REM sleep, the sleep stage where you are most likely to have vivid dreams, you may experience more vivid dreams or nightmares32 . Nightmares can disrupt your sleep, which may lead to an exacerbation of symptoms33 for those with underlying mental health conditions.    

Is melatonin bad for your liver or kidneys?

There is conflicting information on this subject. The NHS recommends that those with liver and kidney issues avoid taking melatonin.10 However, some clinical studies reported no damaging effects34 on the liver from melatonin use, and additional studies are looking into melatonin’s potential healing effects on both the liver35 and kidneys36.

Like many things with melatonin, research is ongoing, which is why it’s always important to follow the guidance of your doctor with melatonin use.

How often is it safe to take melatonin?

A general recommendation for adults is to take melatonin consistently for a maximum of 13 weeks, and for children, a maximum of three weeks.29, 30 Your doctor can give you more individualized recommendations about how best to use melatonin.

Natalie Grigson

Natalie Grigson


About Author

Natalie is a content writer for Sleep Advisor with a deep passion for all things health and a fascination with the mysterious activity that is sleep. Outside of writing about sleep, she is a bestselling author, improviser, and creative writing teacher based out of Austin.

Side Sleeper


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