What Is the Melatonin Hormone and Why Is It Important?

Melatonin is a vital hormone that regulates our sleep-wake cycle, is naturally secreted at night, and controls the body’s internal clock. However, this “sleep hormone” does much more than just initiating sleep. It plays a key role in many essential processes from supporting the immune system and cellular regeneration to balancing hormones and providing antioxidant defense.

Modern life with its artificial lighting, screen exposure, and irregular sleep patterns often disrupts melatonin production, leading to serious consequences for both physical and mental health. In this article, we explore the functions of melatonin in the body, the problems caused by its deficiency, and how to support its production naturally, all from a scientific perspective.

What Is Melatonin?

Melatonin is a hormone secreted by the pineal gland, a small gland located near the center of the brain. Its secretion is directly linked to our circadian rhythm — our biological clock. It is especially active in the dark; daylight or artificial lighting suppresses its production.

Melatonin is synthesized indirectly from the amino acid tryptophan through serotonin. Serotonin is active during the day and is converted into melatonin at night to prepare us for sleep. Therefore, individuals with low serotonin levels may also experience insufficient melatonin production.

Functions of the Melatonin Hormone

The functions of the melatonin hormone in the human body are as follows;

Sleep Regulation

Melatonin is the primary biological signal that initiates sleep. Based on light input from our eyes, the brain either starts or stops melatonin secretion. Its increased secretion in the evening causes drowsiness and stays at a certain level throughout the night.

•  Jet lag, night shifts, and sleep disorders disrupt this natural cycle and desynchronize melatonin release.
• In such cases, low-dose melatonin supplements may help resynchronize the body.
  

Antioxidant Protection and Cell Renewal

Melatonin is a powerful antioxidant that fights free radicals. Scientific studies have shown its protective effect against DNA damage in cells.

• It particularly protects brain cells from oxidative stress, providing a defense against neurodegenerative diseases such as Alzheimer’s and Parkinson’s.
  
• By supporting cellular renewal, it also has the potential to delay signs of aging.
  

Strengthening the Immune System

Melatonin increases the production and activity of immune cells, strengthening the body’s defense mechanism against infections. Studies have shown that individuals with low melatonin levels have more vulnerable immune responses.

• Some research during the COVID-19 pandemic suggested that melatonin could help balance the immune system by suppressing cytokine storms.
  
• It may also reduce inflammation and lower the risk of autoimmune diseases.
  

Hormonal Balance and Reproductive Health

Melatonin plays a significant role not only in sleep but also in hormonal regulation. It indirectly supports processes such as regulating the menstrual cycle in women and maintaining balanced testosterone levels in men.

• Hormonal changes during menopause can affect melatonin production.
  
• Some fertility studies have shown that melatonin may positively influence egg quality and embryo development.
  

Symptoms and Causes of Melatonin Deficiency

Modern lifestyle habits are among the biggest triggers of melatonin deficiency. Exposure to screens during sleep hours, staying up late, stress, and aging all reduce melatonin production.

Common Symptoms of Melatonin Deficiency

• Trouble falling asleep, frequent waking, not feeling rested
  
• Chronic fatigue, lack of concentration
  
• Weakened immunity, frequent illness
  
• Mood disorders, anxiety, and depression
  
• Early signs of aging
  
• Hormonal imbalances, irregular menstruation
  

Is Melatonin Supplementation Necessary?

Melatonin supplements can be effective as a short-term solution in cases such as jet lag, shift work, or insomnia.

When Should You Take a Melatonin Supplement?

• For short-term sleep disorders
  
• To adapt to time zone differences after jet lag
  
• To regulate the sleep cycle after a brain injury
  
• For elderly individuals whose natural production has declined
  

How to Increase Melatonin Naturally

Melatonin levels can also be increased without medication. Small lifestyle changes can make a big difference:

• Avoid screens at least one hour before bedtime
  
• Use dim lighting before sleep
  
• Avoid caffeine consumption in the evening
  
• Sleep in complete darkness at night
  
• Get adequate daylight exposure during the day
  
• Exercise regularly
  
• Consume foods rich in tryptophan (e.g., turkey, milk, oats, bananas, almonds)
  

Conclusion

Melatonin is crucial not just for quality sleep but also for overall health and well-being. If you want to improve your sleep, strengthen your immune system, and delay cellular aging, you should pay attention to maintaining healthy melatonin levels.

If you consider taking supplements, do so consciously and with professional guidance.
Remember: a healthy body begins with a balanced biological clock.

Reference

FNG & Bilim Tıp Dergisi 2017;3(1):52-62