When you haven’t slept well, you feel it. From not quite nailing it at work, to missing exercise goals or feeling “off” with friends, it can be a serious downer – especially when you lose a few nights in a row. 

It’s no surprise, then, that more and more people are reaching for supplements like melatonin for better sleep. But what is it, and how does melatonin help sleep? In this article, we’ll discuss the scientific research on melatonin and advice on taking it.

What is Melatonin?

Melatonin supplements are a sleep aid – but not like you think. They don’t have the cartoonish (and slightly unnerving) ability to put you out like a light, for one. Instead, they work to support your body’s existing internal sleep routine, as your body is already familiar with melatonin: you create it naturally on a daily basis.

Melatonin is a hormone that’s produced by the pineal gland in your brain and released in your body every evening. It’s known as the “sleep hormone” because its primary function is to make you drowsy, though it has other health benefits like promoting eye health and preventing heartburn, and is implicated in mood regulation, learning, and immunity.

Your body produces melatonin as part of your circadian rhythm, which is the body’s natural sleep-wake cycle influenced by light and darkness. Darkness at night causes your eyes to signal to the hypothalamus in your brain that it’s time to sleep, which in turn signals to release melatonin. This is why it’s harder to sleep during the day: your body is programmed to produce melatonin for better sleep at night.

Melatonin supplements are a man-made version of this. They’re processed by the body in the same way, making you fall asleep quicker and less likely to wake up in the night.

How Does Melatonin Work?

Your body’s natural melatonin chemically causes drowsiness and lowers your body temperature. How it does this, however, is still somewhat of a mystery. We know that melatonin binds to receptors on cells, helping you to relax. For example, when melatonin binds to receptors in the brain, it reduces nerve activity. Melatonin also inhibits dopamine, the hormone that makes you alert.

Melatonin supplements have the same chemical structure and bind to receptors with the same effects. Research shows melatonin supplements reduce the time it takes to fall asleep by an average of 7 minutes, promotes better quality sleep, and can reduce jet lag.

Does melatonin work well? As a support, yes. multiple studies have shown melatonin’s effectiveness at supporting the natural sleep cycle, making you feel drowsy so you can get better sleep. 

How Much Should I Take?

When should you take melatonin? If your body doesn’t make enough melatonin naturally, supplements can help. Many factors could contribute to this, from stress and smoking to blue light at night. It’s important to consider these and take steps to improve them too.

How much melatonin will help you sleep? Make sure to take supplements at the right time and start with a lower dose. For example, start with 0.5 mg or 1 mg around 30 minutes before going to bed. If you don’t get sleepy, wait another day and try increasing your dose to 3–5 mg. To treat jet lag, take melatonin two hours before your bedtime at your destination, starting a few days before your trip.

The key is to be patient. Taking too high a dose can cause side effects such as headaches, nausea, dizziness or irritability. Taking melatonin at the wrong time of day could reset your circadian rhythm unfavourably, meaning you’re drowsy when you want to be awake and vice versa.

What to Look Out For

Current evidence suggests that melatonin supplements are safe, non-toxic and not addictive. However, not all melatonin is created equal, so make sure what you’re getting is the real deal. To stay on the safe side, take the following into consideration:

• Check you the melatonin you source in the UK is given after being issued a prescription. As it is not available over-the-counter here in the UK and you want to ensure it’s from a trusted source.
  
• Be aware that “natural” doesn’t always mean “safe.” Your body naturally produces melatonin, but “natural” supplements may have come from the pineal gland of an animal. Stick to synthetic melatonin, as it’s safer.
  
• Melatonin is most often prescribed for adults aged 55+ to help short-term sleep problems, so most courses are 1 to 4 weeks. It is however licensed for use upto 13 weeks. Melatonin could be effective at any age, but consult a pediatrician before administering it to your kids. Additionally, if sleep problems persist, try other ways to improve sleep.
  
• Melatonin supplements may raise blood-sugar and increase blood pressure levels if you take hypertension medications. Additionally, If you’ve had an allergic reaction to medicines in the past, have liver or kidney problems, or an autoimmune condition, consult your doctor.
  
• You should avoid drinking too much alcohol or smoking while taking melatonin, as this prevents it working as well as it should.
  
• If you accidentally take too much of melatonin, it’s unlikely to harm you. However, it’s important to follow label instructions, and if unwanted symptoms occur, stop taking it.

The important thing to remember is melatonin – including your natural melatonin – is a sleep support. It’s a great way to make you feel ready for bed, but you shouldn’t rely on it alone for better sleep. Make it part of a routine of healthy habits, and sleep hygiene methods and you’ll feel its benefits.

References

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Nava Zisapel (2018). New perspectives on the role of melatonin in human sleep, circadian rhythms and their regulation: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6057895/

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Gianluca Tosini, Kenkichi Baba, Christopher K. Hwang, and P. Michael Iuvone (2012). Melatonin: An Underappreciated Player in Retinal Physiology and Pathophysiology: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3462291/

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Melvyn R Werbach (2008). Melatonin for the treatment of gastroesophageal reflux disease; https://www.ncbi.nlm.nih.gov/pubmed/18616070

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National Library of Medicine – Melatonin: https://pubchem.ncbi.nlm.nih.gov/compound/Melatonin

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C Cajochen, K Kräuchi, A Wirz-Justice (2003). Role of melatonin in the regulation of human circadian rhythms and sleep; https://www.ncbi.nlm.nih.gov/pubmed/12622846

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Mucahit Emet, Halil Ozcan, Lutfu Ozel, Muhammed Yayla, Zekai Haliciand Ahmet Hacimuftuoglu (2016). A Review of Melatonin, Its Receptors and Drugs: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4970552/

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Nava Zisapel (2001). Melatonin–Dopamine Interactions: From Basic Neurochemistry to a Clinical Setting: https://link.springer.com/article/10.1023/A:1015187601628

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Eduardo Ferracioli-Oda, Ahmad Qawasmi and Michael H. Bloch(2013). Meta-Analysis: Melatonin for the Treatment of Primary Sleep Disorders: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3656905/

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J. ARENDT, M. ALDHOUS, J. ENGLISH, V. MARKS, J. H. ARENDT, M. MARKS & S. FOLKARD (1987). Some effects of jet-lag and their alleviation by melatonin: https://www.tandfonline.com/doi/abs/10.1080/00140138708966031?casa_token=YTmIn08jVf0AAAAA:4yRCTp84zG4CIRwuD6ZEaGv_PjGlfzQjtV9dibFGJoIPGjSXWlS7OS3ULcc-l7PO6DR8AiZUsEL0

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Rebecca B Costello, Cynthia V Lentino, Courtney C Boyd, Meghan L O’Connell, Cindy C Crawford, Meredith L Sprengel, and Patricia A Deuster *2014). The effectiveness of melatonin for promoting healthy sleep: a rapid evidence assessment of the literature: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4273450/

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Iain M. McIntyre BSc, MSc, PhD, Trevor R. Norman BSc, PhD, Graham D. Burrows MD, FRCP sych, Gregory F. Oxenkrug MD, PhD (1989). The effect of stress on melatonin and serotonin in rat brain: https://onlinelibrary.wiley.com/doi/abs/10.1002/smi.2460050104

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NHS – Melatonin -for sleep problems: https://www.nhs.uk/medicines/melatonin/

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Leena Tähkämö, Timo Partonen, Anu-Katriina Pesonen (2019). Systematic review of light exposure impact on human circadian rhythm: https://www.ncbi.nlm.nih.gov/pubmed/30311830

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B Guardiola-Lemaître (1997). Toxicology of melatonin: https://www.ncbi.nlm.nih.gov/pubmed/9406047

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Medical News Today – Are melatonin and alcohol safe to mix?: https://www.medicalnewstoday.com/articles/319559

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Medical News Today – All you need to know about melatonin: https://www.medicalnewstoday.com/articles/232138

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NIH – Melatonin: What You Need To Know: https://www.nccih.nih.gov/health/melatonin-what-you-need-to-know

While we've ensured that everything you read on the Health Centre is medically reviewed and approved, information presented here is not intended to be a substitute for professional medical advice, diagnosis, or treatment. It should never be relied upon for specific medical advice. If you have any questions or concerns, please talk to your doctor.