You’ve probably heard the buzz about melatonin. Whether it’s your neighbor who swears it’s the secret to their sound sleep or the endless articles touting its myriad health benefits, melatonin is having a moment. And for a good reason. It’s a crucial component of your circadian rhythm, which not only regulates sleep but most aspects of your health.
Though I’ve titled this post as a “complete guide,” it’s written for the average person who’s interested in improving their health without needing to delve too deep into scientific research. For those who enjoy reading research, I strongly recommend reading Is Melatonin the “Next Vitamin D”?: A Review of Emerging Science, Clinical Uses, Safety, and Dietary Supplements. Some friends and colleagues are the authors, and I don’t know that I’ve ever come across such a comprehensive publication about this hormone.
As for this article, I’ll get deep enough for you to appreciate melatonin’s role in your health and provide enough answers that you should be able to share its value with friends and family when the topic comes up.
What is Melatonin?
Melatonin is a hormone, a chemical messenger in your body. Produced primarily in your pineal gland—a tiny organ in your brain—melatonin is your body’s natural “sleep hormone.”1Reiter, R. J., Tan, D. X., Kim, S. J., & Manchester, L. C. (2014). Melatonin: A multitasking molecule. Progress in Brain Research, 181, 127–151.
But it’s is more than just a sleep hormone; it’s a fascinating chemical. Officially known as N-acetyl-5-methoxytryptamine, melatonin has a specific structure that allows it to easily cross cell membranes and even the blood-brain barrier.2Zisapel, N. (2018). New perspectives on the role of melatonin in human sleep, circadian rhythms, and their regulation. British Journal of Pharmacology, 175(16), 3190–3199. This unique trait is what enables it to have such widespread effects on the body.
While your body produces its own melatonin, you can also find it in certain foods like cherries, grapes, and tomatoes.3Howatson, G., Bell, P. G., Tallent, J., Middleton, B., McHugh, M. P., & Ellis, J. (2012). Effect of tart cherry juice (Prunus cerasus) on melatonin levels and enhanced sleep quality. European Journal of Nutrition, 51(8), 909–916. Some people opt for melatonin supplements, which usually come in pill or liquid form, to help them get the full range of its benefits.
So, how does melatonin help you sleep? Think of it as the conductor of your body’s biological orchestra. As evening approaches, levels rise, telling your body to lower its temperature and prepare for rest.4Lewy, A. J., Wehr, T. A., Goodwin, F. K., Newsome, D. A., & Markey, S. P. (1998). Light suppresses melatonin secretion in humans. Science, 210(4475), 1267–1269. It essentially sets the stage for a good night’s sleep by working in sync with your body’s natural circadian rhythm.
Health Benefits of Melatonin
If there’s one thing melatonin is famous for, it’s sleep. Supplementing with it can help you fall asleep faster and even improve the quality of your sleep.5Ferracioli-Oda, E., Qawasmi, A., & Bloch, M. H. (2013). Meta-analysis: Melatonin for the treatment of primary sleep disorders. PLOS ONE, 8(5), e63773. While it’s not a one-size-fits-all solution, it’s a go-to for many who struggle with sleep issues.
Melatonin works by influencing your body’s internal clock. It encourages the physiological changes needed for sleep, such as muscle relaxation and lowered body temperature.6Zisapel, N. (2018). New perspectives on the role of melatonin in human sleep, circadian rhythms, and their regulation. British Journal of Pharmacology, 175(16), 3190–3199.
Dosage can vary, but a common starting point is around 1 to 3 mg about 30 minutes before bedtime. However, it’s always wise to consult with a healthcare provider for personalized advice.7Auld, F., Maschauer, E. L., Morrison, I., Skene, D. J., & Riha, R. L. (2017). Evidence for the efficacy of melatonin in the treatment of primary adult sleep disorders. Sleep Medicine Reviews, 34, 10–22.
- Immune System Support: Beyond sleep, melatonin plays a role in immune system regulation. It can act as an immunostimulant, bolstering your body’s natural defenses.8Carrillo-Vico, A., Guerrero, J. M., Lardone, P. J., & Reiter, R. J. (2005). A review of the multiple actions of melatonin on the immune system. Endocrine, 27(2), 189–200.
- Mental Health: Interestingly, melatonin has shown promise in alleviating symptoms of anxiety and depression, although more research is needed in this area.9Srinivasan, V., Pandi-Perumal, S. R., Cardinali, D. P., Poeggeler, B., & Hardeland, R. (2006). Melatonin in anxiety and stress in humans. In Melatonin: From Molecules to Therapy. Nova Science.
- Antioxidant Properties: Melatonin is also a powerful antioxidant, meaning it helps combat oxidative stress that can lead to cellular damage.10Reiter, R. J., Mayo, J. C., Tan, D. X., Sainz, R. M., Alatorre-Jimenez, M., & Qin, L. (2016). Melatonin as an antioxidant: Under promises but over delivers. Journal of Pineal Research, 61(3), 253–278.
How Does Melatonin Work?
At its core, melatonin is a hormone that acts as a signaling molecule. It binds to receptors—specifically MT1 and MT2 receptors—in various parts of the body, including the brain, to exert its effects.11Dubocovich, M. L., Delagrange, P., Krause, D. N., Sugden, D., Cardinali, D. P., & Olcese, J. (2010). International Union of Basic and Clinical Pharmacology. LXXV. Nomenclature, classification, and pharmacology of G protein-coupled melatonin receptors. Pharmacological Reviews, 62(3), 343–380.
When it binds to these receptors in the brain, particularly in an area called the suprachiasmatic nucleus, it triggers a cascade of events, inhibiting the release of neurotransmitters that promote wakefulness, like dopamine and serotonin. At the same time, melatonin stimulates the release of gamma-aminobutyric acid (GABA), a neurotransmitter that promotes relaxation and sleep.12Golombek, D. A., Pandi-Perumal, S. R., Brown, G. M., & Cardinali, D. P. (2015). Some implications of melatonin use in chronopharmacology of insomnia. European Journal of Pharmacology, 762, 42–48. This intricate balance sets the stage for sleep by calming your nervous system and lowering your body’s core temperature.
Interaction with Other Hormones and Systems
Melatonin doesn’t work in a vacuum; it interacts with a host of other hormones and bodily systems.13Claustrat, B., Brun, J., & Chazot, G. (2005). The basic physiology and pathophysiology of melatonin. Sleep Medicine Reviews, 9(1), 11–24.
- Cortisol: Melatonin affects cortisol secretion, the “stress hormone.” By doing so, it helps modulate your stress levels and can improve sleep quality.
- Insulin: Melatonin also has an interesting relationship with insulin, the hormone responsible for regulating blood sugar. Some research suggests that it might affect insulin sensitivity, which could then impact metabolic health.14Peschke, E., Bähr, I., & Mühlbauer, E. (2013). Melatonin and pancreatic islets: interrelationships between melatonin, insulin and glucagon. International Journal of Molecular Sciences, 14(4), 6981–7015.
Influence on the Immune System
Melatonin also plays a role in the immune system. It can modulate the production of cytokines, which are signaling molecules in the immune system that help regulate inflammation.15Carrillo-Vico, A., Guerrero, J. M., Lardone, P. J., & Reiter, R. J. (2005). A review of the multiple actions of melatonin on the immune system. Endocrine, 27(2), 189–200.
Melatonin and Age
As you age, it’s not just your joints that might creak a little more; your melatonin production can also decline. Research shows that levels tend to peak during childhood and gradually decrease as you get older.16Zeitzer, J. M., Daniels, J. E., Duffy, J. F., Klerman, E. B., Shanahan, T. L., Dijk, D. J., & Czeisler, C. A. (1999). Do plasma melatonin concentrations decline with age? The American Journal of Medicine, 107(5), 432–436. This decline is one reason why older adults often experience changes in sleep patterns and quality.
Despite the natural decline, melatonin plays a crucial role in health as you age. For older adults, supplementing with it can not only improve sleep but also offer other health benefits. Some studies have shown that it can help improve mood and cognitive function in older adults.17Wade, A. G., Ford, I., Crawford, G., McConnachie, A., Nir, T., Laudon, M., & Zisapel, N. (2010). Nightly treatment of primary insomnia with prolonged release melatonin for 6 months: a randomized placebo-controlled trial on age and endogenous melatonin as predictors of efficacy and safety. BMC Medicine, 8, 51.
Melatonin and Age-Related Diseases
As we age, our bodies become more susceptible to a range of diseases, many of which are influenced by oxidative stress and inflammation. Melatonin’s antioxidant and anti-inflammatory properties make it a subject of interest for researchers studying age-related diseases.18Srinivasan, V., Pandi-Perumal, S. R., Cardinali, D. P., Poeggeler, B., & Hardeland, R. (2010). Melatonin in Alzheimer’s disease and other neurodegenerative disorders. Behavioral and Brain Functions, 2(1), 15.
One of the most devastating age-related diseases is Alzheimer’s. Research suggests that melatonin could play a role in protecting neural cells from the damage that leads to Alzheimer’s. Studies have shown that it can inhibit the aggregation of beta-amyloid plaques, a key factor in the progression of the disease.19Zhang, W., Chen, X. Y., Su, S. W., Jia, Q. Z., Ding, T., Zhu, Z. N., & Zhang, T. (2016). Exogenous melatonin for sleep disorders in neurodegenerative diseases: A meta-analysis of randomized clinical trials. Neuropsychiatric Disease and Treatment, 12, 309.
Similarly, in Parkinson’s disease, melatonin has been shown to protect dopaminergic neurons from degeneration. It does this by combating oxidative stress, thereby potentially slowing the progression of the disease.20Antolín, I., Mayo, J. C., Sainz, R. M., del Brío, M. d. l. Á., Herrera, F., Martín, V., & Rodríguez, C. (2002). Protective effect of melatonin in a chronic experimental model of Parkinson’s disease. Brain Research, 943(2), 163–173.
Melatonin’s effects aren’t just limited to the nervous system. It also has implications for cardiovascular health. It has been found to improve lipid profiles and reduce blood pressure, which are significant factors in cardiovascular diseases that often appear with age.21Simko, F., & Paulis, L. (2007). Melatonin as a potential antihypertensive treatment. Journal of Pineal Research, 42(4), 319–322.
Last but not least, melatonin has shown promise in maintaining cognitive function in older adults. Some studies indicate that melatonin supplementation can improve attention, memory, and overall cognitive performance, although more research is needed to confirm these effects.22Wade, A. G., Ford, I., Crawford, G., McConnachie, A., Nir, T., Laudon, M., & Zisapel, N. (2010). Nightly treatment of primary insomnia with prolonged release melatonin for 6 months: a randomized placebo-controlled trial on age and endogenous melatonin as predictors of efficacy and safety. BMC Medicine, 8, 51.
Dosage and Timing
When it comes to melatonin, more isn’t always better. The right dosage and timing can make a significant difference in its effectiveness.
The “starter” dose for adults looking to improve sleep is usually around 1 to 3 mg, taken about 30 minutes to an hour before bedtime.23Auld, F., Maschauer, E. L., Morrison, I., Skene, D. J., & Riha, R. L. (2017). Evidence for the efficacy of melatonin in the treatment of primary adult sleep disorders. Sleep Medicine Reviews, 34, 10–22. Some may find lower doses effective, while others might need a bit more.
Melatonin isn’t a one-size-fits-all solution. Factors such as age, health conditions, and even the type of sleep issues you’re experiencing can influence the ideal dosage and timing.24Zisapel, N. (2018). New perspectives on the role of melatonin in human sleep, circadian rhythms, and their regulation. British Journal of Pharmacology, 175(16), 3190–3199. Always consult with a healthcare provider for personalized advice.
Extended-Release vs. Immediate-Release
There are different forms of melatonin supplements available, including immediate-release and extended-release options. Immediate-release helps you fall asleep quickly, while extended-release keeps levels elevated throughout the night for sustained sleep.25Wade, A. G., Ford, I., Crawford, G., McConnachie, A., Nir, T., Laudon, M., & Zisapel, N. (2010). Nightly treatment of primary insomnia with prolonged release melatonin for 6 months: a randomized placebo-controlled trial on age and endogenous melatonin as predictors of efficacy and safety. BMC Medicine, 8, 51.
The Importance of Timing
Timing is crucial when taking melatonin. Taking it too early or too late can disrupt your body’s natural circadian rhythm. It’s generally best to stick to a consistent schedule when supplementing with melatonin to get the most benefits.26Lewy, A. J., Wehr, T. A., Goodwin, F. K., Newsome, D. A., & Markey, S. P. (1998). Light suppresses melatonin secretion in humans. Science, 210(4475), 1267–1269.
Risks and Side Effects
While melatonin is generally considered safe for short-term use, it’s important to be aware of potential risks and side effects.
Common short-term side effects include headaches, dizziness, and nausea. These usually subside on their own but can be bothersome.27Andersen, L. P. H., Gögenur, I., Rosenberg, J., & Reiter, R. J. (2016). The Safety of Melatonin in Humans. Clinical Drug Investigation, 36(3), 169–175.
The long-term safety of melatonin is a subject still under investigation. While it’s generally considered safe for short-term use, there are concerns about extended usage.
- Fertility implications: Some animal studies have suggested that prolonged exposure might affect reproductive health, specifically by influencing hormone levels that are crucial for fertility.28Kennaway, D. J. (2015). Potential safety issues in the use of the hormone melatonin in paediatrics. Journal of Paediatrics and Child Health, 51(6), 584–589.
- Exacerbation of Mood Disorders: For those with pre-existing mood disorders like depression or anxiety, long-term use might exacerbate symptoms. Some research has indicated that melatonin can influence serotonin and dopamine levels, which are key neurotransmitters involved in mood regulation.29Lewy, A. J., Emens, J. S., Songer, J. B., Sims, N., Laurie, A. L., Fiala, S. C., & Buti, A. L. (2006). Winter Depression: Integrating mood, circadian rhythms, and the sleep/wake and light/dark cycles into a bio-psycho-social-environmental model. Sleep Medicine Clinics, 1(2), 219–230.
- Hormonal Imbalance: Given that melatonin is a hormone, there is also the potential for it to interact with or disrupt other hormonal systems in the body when used over an extended period.30Zhdanova, I. V. (2005). Melatonin as a hypnotic: pro. Sleep Medicine Reviews, 9(1), 51–65.
- Unknown Long-Term Effects: It’s also worth noting that because melatonin is a relatively new subject of research, there may be other long-term effects that are not yet known. As such, it’s advisable to exercise caution and consult with a healthcare provider for long-term use.31Andersen, L. P. H., Gögenur, I., Rosenberg, J., & Reiter, R. J. (2016). The Safety of Melatonin in Humans. Clinical Drug Investigation, 36(3), 169–175.
Melatonin can interact with various medications, including anticoagulants, anticonvulsants, and blood pressure medications. Always consult a healthcare provider if you’re taking other medications.
Who Should Avoid Taking Melatonin
Certain populations should exercise caution. Pregnant and breastfeeding women, as well as individuals with liver disorders, should avoid melatonin unless advised otherwise by a healthcare provider.32American Academy of Sleep Medicine. (2007). Sleep-related breathing disorders in adults: recommendations for syndrome definition and measurement techniques in clinical research. Sleep, 22(5), 667–689.
Frequently Asked Questions
While it is generally safe for short-term use, its long-term safety is still under investigation. If you find the need to take melatonin consistently, it’s best to consult with a healthcare provider for personalized advice.
Unlike some sleep medications, melatonin is not known to cause physical dependency. However, psychological dependency can occur with any substance used as a sleep aid.
Melatonin has been used in children for sleep disorders, but it’s crucial to consult a pediatrician for proper dosage and timing, as the hormone’s effects can be different in younger populations.33Kennaway, D. J. (2015). Potential safety issues in the use of the hormone melatonin in paediatrics. Journal of Paediatrics and Child Health, 51(6), 584–589.
It’s generally advised that pregnant and breastfeeding women avoid it unless specifically recommended by a healthcare provider.34American Academy of Sleep Medicine. (2007). Sleep-related breathing disorders in adults: recommendations for syndrome definition and measurement techniques in clinical research. Sleep, 22(5), 667–689.
Feeling groggy the morning after taking it is a common experience for some people. This is often referred to as a “melatonin hangover.” It can occur if the dose is too high or if the timing of the dose is not aligned with your natural circadian rhythm.
Melatonin primarily aids in the initiation of sleep and is less involved in influencing the stages of sleep, such as Deep and REM sleep. However, some studies suggest that it can increase REM sleep time and REM sleep percentage. The effects on Deep sleep are less clear, and more research is needed to fully understand its role in sleep architecture.35Zisapel, N. (2018). New perspectives on the role of melatonin in human sleep, circadian rhythms, and their regulation. British Journal of Pharmacology, 175(16), 3190–3199.
Melatonin is far more than just a sleep aid. From its role in regulating your body’s circadian rhythm to its potential benefits for immune support, mental health, and even age-related diseases, it is a multi-faceted hormone that can impact various aspects of your well-being.
However, like any supplement, it’s not without its risks. Short-term use is generally considered safe, but the long-term effects are still under investigation. Always consult with a healthcare provider for personalized advice on dosage and timing, especially if you’re considering long-term use or have pre-existing health conditions.
In the ever-evolving landscape of health and wellness, staying informed is key. And when it comes to understanding the health benefits of melatonin, you’re now well-equipped with the knowledge you need to make informed decisions.