Melatonin: The Sleep Hormone and Beyond

Melatonin, often referred to as the “sleep hormone,” plays a crucial role in regulating our sleep-wake cycle, also known as the circadian rhythm. Produced by the pineal gland, a small pinecone-shaped structure located deep within the brain, melatonin levels rise in response to darkness, signaling to the body that it's time for sleep. This natural process helps us fall asleep more easily and maintain sleep throughout the night. [1]

Melatonin: Types, Symptoms, Causes, Risk, Treatments and More

Melatonin Production and Regulation

The production of melatonin is heavily influenced by light exposure. According to research during darkness, the pineal gland receives signals from the eyes and ramps up melatonin production. [2]

Conversely, exposure to light, particularly blue light emitted from electronic devices, suppresses melatonin production. This explains why staring at screens before bed can disrupt sleep – it tricks your body into thinking it's still daytime, delaying the release of melatonin.

Several factors can affect melatonin production besides light exposure. As we age, the pineal gland naturally becomes less efficient at producing melatonin, leading to potential sleep disturbances in older adults. Additionally, certain medical conditions, shift work, and jet lag can all disrupt the body's natural production of melatonin. [3]

Types of Melatonin

Melatonin can be categorized based on its source:

Dietary Sources: Small amounts may be found in:

  • Tart cherries
  • Kiwifruit
  • Walnuts
  • Almonds

Supplements: Available in various forms:
Dosage Forms:

  • Tablets
  • Capsules
  • Gummies
  • Liquids (varying absorption rates)

Release Mechanisms:

  • Standard release
  • Sustained release (gradual release throughout the night)

Symptoms of Melatonin Imbalance

When melatonin production is disrupted, it can lead to a variety of sleep-related issues. The most common symptom of melatonin imbalance is insomnia, characterized by difficulty falling asleep or staying asleep throughout the night. Additionally, you might experience excessive daytime fatigue, difficulty concentrating, and irritability. [6]

Melatonin imbalance can also manifest as a disrupted sleep-wake cycle. This is particularly noticeable with jet lag, where rapid travel across time zones throws off the body's internal clock. People with jet lag might experience daytime sleepiness and difficulty sleeping at night due to the mismatch between their natural melatonin production and the local light-dark cycle.

Causes of Melatonin Imbalance

Several factors can contribute to melatonin imbalance. Recent studies highlighted shift work, which disrupts the body's natural sleep-wake cycle, is a common culprit. Frequent travel across time zones, leading to jet lag, also throws off melatonin production. Age-related decline in melatonin production is another factor, with older adults often experiencing more sleep disturbances. [7]

Certain medical conditions can also affect melatonin production. Sleep apnea, a disorder characterized by pauses in breathing during sleep, can disrupt sleep patterns and potentially impact melatonin levels. Additionally, neurological disorders like Parkinson's disease and Alzheimer's disease may be linked to melatonin dysfunction.

Risks and Side Effects of Melatonin Use

While generally safe for short-term use, melatonin supplements can cause side effects in some individuals. These side effects are usually mild and may include headaches, dizziness, nausea, and daytime drowsiness. Melatonin can also interact with certain medications, so it's essential to discuss any supplements you're taking with your doctor before starting melatonin.

Pregnant or breastfeeding women should avoid using melatonin supplements unless explicitly advised by a doctor. The long-term effects of melatonin on developing fetuses and infants are not fully understood.

Treatments for Melatonin Imbalance

melatonin supplements

Melatonin Supplements. Shutterstock Image

Before resorting to melatonin supplements, it's crucial to address the underlying cause of melatonin imbalance whenever possible. If your sleep problems are related to shift work, try to develop a consistent sleep schedule, even on your off days. Light therapy, which involves exposure to bright light in the morning, can help regulate your circadian rhythm. [8]

Creating a good sleep hygiene routine is essential for promoting healthy sleep patterns regardless of melatonin levels. This includes establishing a regular sleep schedule, going to bed, and waking up at the same time each day, even on weekends.

Creating a relaxing bedtime routine that signals to your body it's time to wind down can also be helpful. This might involve taking a warm bath, reading a book, or practicing relaxation techniques like meditation. If lifestyle changes and good sleep hygiene practices don't improve your sleep, your doctor might recommend melatonin supplements.

Recent research published by the National Institute of Medicine indicates that Carbohydrates also play a significant role in promoting the production of melatonin, the hormone responsible for regulating sleep-wake cycles. [9]

When consumed as part of a balanced diet, carbohydrates can positively influence melatonin levels, thereby contributing to better sleep quality. It's important to start with a low dose of melatonin supplements and increase gradually only under medical supervision. Melatonin supplements are typically recommended for short-term use, and long-term use should be discussed with your doctor.


In summary, melatonin, known as the “sleep hormone,” plays a vital role in regulating our sleep-wake cycle. Produced naturally by the pineal gland, its levels rise in response to darkness, signaling the body that it's time for sleep.

While melatonin can be found in small amounts in certain foods like tart cherries and almonds, supplements are readily available in various forms to address melatonin imbalances.

However, caution is advised when using supplements due to potential side effects, and it's essential to consult a healthcare professional before starting melatonin supplementation.

Lifestyle modifications, such as maintaining a consistent sleep schedule and practicing good sleep hygiene, can complement melatonin supplementation in promoting healthy sleep patterns.

By understanding the types and functions of melatonin and implementing appropriate strategies, individuals can work towards achieving better sleep and overall well-being.

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9 Sources

We review published medical research in respected scientific journals to arrive at our conclusions about a product or health topic. This ensures the highest standard of scientific accuracy.

[1] Masters A, Pandi-Perumal SR, Seixas A, Girardin JL, McFarlane SI. Melatonin, the Hormone of Darkness: From Sleep Promotion to Ebola Treatment. Brain Disord Ther. 2014;4(1):1000151. doi: 10.4172/2168-975X.1000151. PMID: 25705578; PMCID: PMC4334454.
[2] Ostrin LA. Ocular and systemic melatonin and the influence of light exposure. Clin Exp Optom. 2019 Mar;102(2):99-108. doi: 10.1111/cxo.12824. Epub 2018 Aug 3. PMID: 30074278.
[3] "Jet lag disorder - Symptoms and causes - Mayo Clinic." Mayo Clinic, 19 Nov. 2022,
[4] Zhdanova IV, Wurtman RJ, Balcioglu A, Kartashov AI, Lynch HJ. Endogenous melatonin levels and the fate of exogenous melatonin: age effects. J Gerontol A Biol Sci Med Sci. 1998 Jul;53(4):B293-8. doi: 10.1093/gerona/53a.4.b293. PMID: 18314560.
[5] Meng X, Li Y, Li S, Zhou Y, Gan RY, Xu DP, Li HB. Dietary Sources and Bioactivities of Melatonin. Nutrients. 2017 Apr 7;9(4):367. doi: 10.3390/nu9040367. PMID: 28387721; PMCID: PMC5409706.
[6] "Pineal Disorders: Melatonin Deficiency and Excess - Restorative Medicine." Restorative Medicine, 14 Mar. 2024,
[7] Brown GM. Light, melatonin and the sleep-wake cycle. J Psychiatry Neurosci. 1994 Nov;19(5):345-53. PMID: 7803368; PMCID: PMC1188623.
[8] "Melatonin: What You Need To Know." NCCIH, 14 Mar. 2024,
[9] Benton D, Bloxham A, Gaylor C, Brennan A, Young HA. Carbohydrate and sleep: An evaluation of putative mechanisms. Front Nutr. 2022 Sep 21;9:933898. doi: 10.3389/fnut.2022.933898. PMID: 36211524; PMCID: PMC9532617.


Sam Kramer is a Registered Dietitian, Licensed Dietitian Nutritionist, Six Sigma Green Belt Certified, and Certified Sports Nutritionis