Hormone Health Hub: Expert Insights on Testing, Balance & Better Living — melatonin and sleep

As the days shorten and sunlight fades, four key hormonal systems come under pressure: vitamin D, serotonin, cortisol and melatonin. For those susceptible to Seasonal Affective Disorder (SAD), the disruption of these interconnected rhythms can trigger depression, fatigue, poor sleep and low mood. This article explains the science behind the SAD hormone pattern — and what you can do to support your body through the darker months.

Melatonin is far more than a sleep supplement — it is a master regulator of the body’s circadian rhythm, a potent antioxidant, and a key signal for cell repair and gene transcription. Understanding how melatonin is produced, what its daily curve looks like, and how it can be accurately measured through first-morning urinary MT6s testing is essential for anyone investigating sleep disturbances, fatigue or hormonal imbalance.