Melatonin and Sleep: Uses, Dosage & Side Effects

Melatonin is a hormone produced by the brain that tells our body when it’s time to sleep. However, many people who suffer from certain sleep disorders turn to synthetic melatonin supplements to help them nod off. In 2020, American consumers spent $825,559,397 on melatonin supplements – a 42.6% increase compared to 2019, highlighting that, as a nation, we’re struggling to get to sleep. In this article, we’re going to cover what melatonin is, how melatonin supplements can help those with certain sleep disorders, and any considerations to keep in mind.

Table of Contents

What is melatonin?

Melatonin is a sleep-promoting hormone produced naturally by the brain’s pineal gland. It helps to regulate our sleep-wake cycle, so our body knows when to feel sleepy and when to feel alert. Our melatonin levels rise around two hours before bedtime, helping us get ready to sleep. 

Melatonin is often referred to as the body’s ‘sleep hormone’, but experts prefer it to be called the ‘darkness hormone’. This is because it doesn’t actually make us fall asleep but rather helps settle the body into a relaxed state in which to fall asleep.

Those who experience difficulty sleeping often have low melatonin levels, and as such, synthetically-made melatonin supplements can help (usually on a short-term basis). Melatonin is available as a dietary supplement in the US. 

Aiding the body’s natural melatonin levels

For most people, getting a successful night’s sleep comes down to practicing good sleep hygiene. Melatonin production decreases during the day when we’re exposed to light and increases in the evening when it’s darker, telling our body to get ready for sleep.

There are several things you can do to aid the body’s natural melatonin production. These include:

  • Getting sunlight exposure in the morning and afternoon
  • Turning the lights down a couple of hours before bed
  • Avoiding screen time a couple of hours before bed
  • Using a blue and green light screen filter when using smart devices before bed

The rest of this guide will focus on melatonin supplements and their uses.

Benefits of melatonin supplements: Who should take them?

Melatonin is mainly used to treat circadian rhythm sleep disorders (sleep disorders that relate to sleep timing), which include:

  • Jet lag
  • Delayed sleep phase disorder 
  • Shift work disorder

Shift work disorder

Shift work disorder affects individuals who work night shifts or rotating schedules and are unable to get quality sleep when the body needs it. Studies have shown that taking melatonin prior to daytime sleep following a night shift can improve sleep quality and duration. However, it fails to increase alertness levels at night when shift workers need to stay awake.

Jet lag disorder

Jet lag is a temporary disorder that affects people who have traveled through multiple time zones in a short time period. It happens when our sleep-wake rhythm becomes out of sync with the local time. Research shows that taking melatonin at the appropriate time can reduce symptoms of jet lag and improve sleep after traveling across multiple time zones. 

Delayed sleep phase disorder

Delayed sleep phase disorder is where individuals struggle to stick to a habitual sleep schedule, usually falling asleep in the early hours of the morning and, as a result, waking up late. When individuals with DSPD stick to their delayed sleep schedule, they generally sleep well, but when an attempt is made to sleep or wake earlier, insomnia and daytime sleepiness can occur. Studies have found that timed melatonin administration in the afternoon or evening can shift the circadian rhythm to an earlier time and reduce sleep onset latency. It hasn’t been found to alter total sleep time or daytime alertness, however.

Insomnia and melatonin

Melatonin is often thought of as a supplement that helps us fall asleep, but experts advise otherwise. 

While the use of melatonin may be helpful for those with occasional short-term insomnia, it’s not recommended for the treatment of chronic primary insomnia due to insufficient evidence around its effectiveness.

Instead, CBT (cognitive behavioral therapy) is recommended as a first-line treatment, alongside adopting healthy sleep habits. Melatonin agonist, ramelteon, is also recommended for chronic sleep-onset insomnia.

There is, however, evidence to suggest that prolonged-release melatonin is a helpful treatment for insomnia in individuals over the age of 55, with patients experiencing improvements in sleep quality, morning alertness, sleep onset latency, and quality of life. This could be related to the fact that our bodies create less melatonin as we age.

Children with sleep problems

There are mixed medical opinions on whether melatonin is safe for use in children. While it can improve sleeping difficulties for some children, it’s agreed that more research is needed on the long-term side effects of the hormone.

Various studies have found melatonin to be particularly helpful in children with neurodevelopmental disorders, such as autism or ADHD (attention-deficit hyperactivity disorder).

Melatonin side effects and precautions

While short-term use of melatonin is thought to be safe for the majority of people, as with any kind of supplement or medication, there are considerations to be made.

Some of the side effects can include:

  • Daytime sleepiness
  • Drowsiness
  • Headaches
  • Dizziness
  • Nausea

As well as the above symptoms, side effects in children include:

  • Agitation 
  • Bedwetting (or increased bedwetting)

While melatonin is available without a prescription in the US, if you’re thinking about taking the supplement or giving it to your child, it’s highly advised to speak with your doctor beforehand. There are various reasons for this.

  • Mixing medicines: If you take other drugs or supplements, speak to your doctor about taking them alongside melatonin. Those taking blood thinners or with epilepsy, for example, will need to be monitored while taking it.
  • Less regulated: In other countries, including the UK, melatonin is only available on prescription. However, because it’s considered a dietary supplement in the US, it’s less strictly regulated by the FDA (Food and Drug Administration). 
  • Incorrect labeling: A 2017 study found that the amount of melatonin in a large proportion of the tested supplements differed from what was listed on the label. It also revealed that the amount of melatonin within individual pills in the same packet varied, too. Additionally, 26% of the tested supplements contained serotonin, a hormone that can have harmful effects.

Tip: Look for the ‘USP Verified’ mark to confirm that the supplement meets the requirements of the U.S. Pharmacopeial Convention.

  • Allergy risk: As with taking any new medication or supplement, there is always an allergy risk. Discussing with your doctor beforehand can help prevent side effects from any known allergies.

Who shouldn’t take melatonin?

Melatonin isn’t for everyone, and, as such, various studies have revealed that the risks outweigh the benefits for individuals in certain categories. If you fall within the categories below, you should avoid taking the supplement or speak with your doctor if you’re thinking about doing so.

Pregnant and breastfeeding women

The body’s naturally produced melatonin plays a big role in pregnancy, with levels dipping in early pregnancy and rising from 24 weeks. However, melatonin supplements aren’t advised for pregnant or breastfeeding women due to a lack of research into their safety.

Individuals with dementia

According to the American Academy of Sleep Medicine, melatonin is not recommended for elderly patients with dementia due to the harms outweighing the benefits.

Individuals with certain health conditions

If you have an autoimmune disorder, a seizure disorder (e.g. epilepsy), depression, diabetes, or high blood pressure, you should speak with your doctor before taking melatonin. 

Children (administer with caution)

Because of the limited studies available on the long-term side effects of melatonin supplements in children, it’s recommended that parents speak with their pediatrician before giving children melatonin for sleep problems. It’s thought that because melatonin is a hormone, it could affect hormonal development, but more research is needed.

The bottom line

While melatonin can help adults and children with certain sleep and neurodevelopmental disorders, it’s not recommended as a long-term solution for everyone. 

Before taking melatonin, be sure to speak with your healthcare provider, who will advise the best treatment for your sleep troubles. If your sleep problems persist after a week or two of taking melatonin, stop taking it and speak to your doctor.

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