Hormone Health Hub: Expert Insights on Testing, Balance & Better Living — diurnal cortisol rhythm

A melanoma diagnosis changes everything — but it can also be the catalyst for a smarter, more proactive approach to skin health. In this personal account, Lissa Gienty of ZRT Laboratory shares her melanoma story and the evidence-based steps she now takes to protect herself, including optimising vitamin D and melatonin levels and monitoring her diurnal hormone rhythms.

Cortisol is your body’s primary stress hormone, produced by the adrenal glands in response to physical, mental and emotional stress. While it plays a vital role in energy metabolism, immune function and cardiovascular health, both chronically high and chronically low cortisol levels can cause significant health problems — from fatigue, weight gain and sleep disorders to burnout and adrenal exhaustion. This article explains what cortisol is, what happens when it goes wrong, and why regular testing matters.

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.

Norepinephrine and epinephrine follow a distinct diurnal rhythm — rising through the morning, peaking in the afternoon, and falling at night. When this pattern is disrupted by chronic stress, the consequences ripple through every hormonal system in the body. Learn how the stress response works and how dried urine testing can reveal imbalances.