During autumn and winter, reduced daylight has a direct impact on many physiological processes in the body, especially hormone balance. In this period, the secretion of key hormones such as melatonin, serotonin, and cortisol changes, which may lead to fatigue, low energy, sleep disturbances, and even depressive symptoms. This article explains, from a scientific perspective, how reduced daylight affects the hormonal system and how to manage these changes correctly.
A hormone is a biologically active substance that regulates the function of organs and systems in the body. When hormonal balance is disrupted, various physical and psychological symptoms may appear, negatively affecting overall health.
Melatonin is a hormone primarily released in darkness. When daylight decreases:
Melatonin levels increase
Daytime sleepiness becomes more pronounced
Overall energy levels decline
For this reason, interest in topics such as what melatonin is and the benefits of melatonin increases during winter. In some cases, the use of melatonin supplements may be considered, but only under professional medical guidance.
Serotonin is commonly known as the “happiness hormone” and is closely linked to sunlight exposure. When daylight decreases:
Serotonin levels drop
Mood may decline
The risk of depression increases
This explains why emotional well-being often worsens during darker months.
Cortisol is known as the stress hormone. Disruption of circadian rhythm due to reduced daylight may cause:
Fluctuations in cortisol levels
Persistent chronic fatigue
Increased emotional tension
When necessary, cortisol levels can be assessed through laboratory testing.
Reduced daylight also leads to decreased natural production of vitamin D in the body. Vitamin D deficiency may:
Negatively affect hormonal regulation
Lower energy levels
Contribute to mood disturbances
Based on laboratory results and with medical advice, vitamin D supplements such as Best plus 10 ml N4 drops, D-Ferol 10 ml drops, or D-kolerol 5000 IU N28 capsules may be used to support vitamin D levels during this period.
Hormonal imbalance related to reduced daylight may present with:
Persistent fatigue
Difficulty concentrating and memory issues
Disrupted sleep patterns
Emotional instability
Decreased motivation
If these symptoms persist, hormonal testing may be recommended.
During winter months, the following tests are commonly requested:
General hormone analysis
Thyroid-stimulating hormone (TSH)
Estrogen levels
Anti-Müllerian hormone (AMH)
Somatotropin (growth hormone)
Luteinizing hormone
These tests help determine whether hormonal medication or targeted supplementation is necessary.
Reduced daylight often disrupts sleep cycles, which may:
Increase the need for depression screening
Raise the risk of major depressive disorder in vulnerable individuals
Early assessment and appropriate lifestyle adjustments are essential during this period.
Yes. Reduced daylight significantly affects melatonin, serotonin, and cortisol levels.
In many cases, yes. Limited sun exposure often leads to vitamin D deficiency.
Melatonin should only be used with medical supervision and for short periods.
Most hormone tests are done via blood samples, typically collected in the morning on an empty stomach.
Reduced daylight has a substantial impact on hormone balance. Changes in melatonin, serotonin, cortisol, and vitamin D levels can affect both physical and mental health. During periods of limited sunlight, hormone testing, proper sleep hygiene, balanced nutrition, and—when necessary—medically supervised use of vitamin D supplements such as Best plus 10 ml N4 drops, D-Ferol 10 ml drops, or D-kolerol 5000 IU N28 capsules can help maintain hormonal balance and overall well-being.
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