What is the Difference Between Circadin and Melatonin

The key difference between circadin and melatonin is that circadin is an artificially synthesized drug utilized to treat insomnia, while melatonin is a naturally synthesized hormone that regulates human sleep patterns.

The biological clock of humans is regulated by different types of hormones synthesized by the body. They control different metabolic functions. Melatonin is a hormone that responds to darkness, managing the biological clock through the regulation of sleep. Insomnia or inability to sleep is a common sleep disorder. Melatonin supplements like Circadin are administered to such patients in order to induce sleep by the prolonged release of melatonin.

CONTENTS

1. Overview and Key Difference
2. What is Circadin  
3. What is Melatonin
4. Similarities – Circadin and Melatonin
5. Circadin vs Melatonin in Tabular Form
6. Summary – Circadin vs Melatonin

What is Circadin?

Circadin is a type of monotherapy drug used to treat primary insomnia, which is characterized by the poor quality of sleep. Circadin consists of melatonin as the active substance. It is available as white 2 mg tablets. Circadin works as a short-term treatment for primary insomnia in patients aged 55 years and above. This type of insomnia usually has no identified cause in the areas of medical, environmental, and mental causes. Hence, circadin is a general drug that causes the prolonged release of melatonin produced by the pineal gland of the human brain.

Figure 01: The Circadian Clock in the Human Brain

The recommended dose of Circadin is one tablet (2mg) per day before bedtime after meals. This could be continued up to 13 weeks. However, the dosage should be decided by a physician based on symptoms. Insomnia is commonly present in older patients since they produce melatonin in lower concentrations. This leads to the development of irregular sleep patterns since the biological clock is not regulated properly. By the administration of circadin, blood melatonin levels go up and help the patient to sleep. Melatonin release by circadin is a slow process that mimics the natural phenomenon conducted by the pineal body of the human brain. Circadin shows very few side effects. Restlessness, abnormal dreams, anxiety, and migraine are the rare side effects of circadin.

What is Melatonin?

Melatonin is a hormone secreted by the pineal body of the brain that involves in regulation of sleep of humans. The natural release of melatonin prevents sleep disorders such as insomnia. Melatonin responds to darkness. Hence it is released during darkness which induces sleep in humans. Therefore, melatonin is an essential component that regulates the biological clock of humans. Even though different tissues of the body secrete melatonin, the primary location is the pineal body with the highest concentration of secretion. Synthesis of melatonin occurs from amino acid tryptophan.

Figure 02: Structure of Melatonin

Detection of darkness occurs by the amount of light that enters our eyes. The optic nerve detects the intensity of light and carries the signal to the pineal body to release melatonin. This is the reason why melatonin is secreted less during the daytime, and humans usually do not fall asleep. In older individuals, due to different defects in the eyes and hormonal productions, secretion of melatonin occurs irregularly. This leads to sleep disorders, which are very common in elderly populations. Circadin is a drug that is used to treat such conditions at the primary levels.

What are the Similarities Between Circadin and Melatonin?

• Circadin and melatonin are sleep inducers.
• Both regulate the biological clock of humans.
• They prevent sleep disorders.
• They possess common characteristics both biochemically and functionally.
• Both types are released into the bloodstream.

What is the Difference Between Circadin and Melatonin?

Melatonin is a naturally synthesized hormone produced by the pineal body of the brain. In contrast, circadin is an artificially synthesized drug involved in the treatment of sleep disorders. Thus, this is the key difference between circadin and melatonin. Circadin is administered to older individuals with low melatonin secretions. Melatonin secretes according to the light intensity detected by the eye and the optic nerve. Circadin has no effect on light intensity.

The below infographic presents the differences between circadin and melatonin in tabular form for side by side comparison.

Summary – Circadin vs Melatonin

Insomnia is a common condition in older individuals. This is due to the irregular or low secretion of the sleep-inducing hormone melatonin. Melatonin is secreted by the pineal gland of the brain. It induces sleep with reference to light intensity. When melatonin production is less and in order to prevent sleep disorders like insomnia, circadin is administered as a therapeutic drug. Its main active ingredient is melatonin. Circadin causes the prolonged release of melatonin that mimics the natural phenomenon of melatonin secretion. So, this summarizes the difference between circadin and melatonin.

Reference:

1. “Circadin: Uses, side effects, benefits/risks.” Drugs.
2. “Melatonin: Overview, uses, side effects, precautions, interactions, dosing and reviews.” WEBMD

Image Courtesy:

1. “The master circadian clock in the human brain” By Ian B Hickie, Sharon L Naismith, Rébecca Robillard, Elizabeth M Scott, and Daniel F Hermens –  Manipulating the sleep-wake cycle and circadian rhythms to improve clinical management of major depression. BMC Medicine. 2013;11:79. doi:10.1186/1741-7015-11-79. (CC BY 3.0) via Commons Wikimedia
2. “Melatonin molecule ball” By Jynto (talk) – Own work  This image was created with Discovery Studio Visualizer. (CC0) via Commons Wikimedia

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