Cortisol Cx4 Saliva Test by ZRT Lab | 4-Point At-Home Kit

Cortisol Cx4 Saliva Hormone Test by ZRT Laboratory measures your cortisol levels four times across a 24-hour period (morning, noon, evening, and bedtime) to map your complete daily cortisol curve. This at-home saliva collection kit provides lab-accurate results that reveal how your adrenal glands are responding to stress — and whether your cortisol rhythm is following its normal healthy pattern.*

What This Test Reveals

• ✅ Your diurnal cortisol curve — is cortisol highest in the morning and declining properly through the day?
• ✅ Adrenal function status — identify patterns of adrenal stress, fatigue, or “burnout”
• ✅ Stress response patterns — understand how prolonged stress may be affecting your cortisol output
• ✅ Sleep disruption clues — elevated bedtime cortisol is a common cause of insomnia
• ✅ Hormone imbalance indicators — adrenal dysfunction can contribute to weight changes and sex hormone imbalances

How It Works

1. Order your kit — we ship the ZRT collection kit directly to you
2. Collect at home — provide 4 saliva samples throughout the day (morning, noon, evening, bedtime) in the privacy of your home or office
3. Mail to ZRT Lab — prepaid shipping included in the kit
4. Receive results — lab-accurate analysis from one of the world’s leading hormone testing laboratories

Why Saliva Testing?

Steroid hormones in the bloodstream are 95–99% bound to carrier proteins and unavailable to target tissues. Saliva testing measures the bioavailable amount — the hormones actually available to your cells. This is why saliva testing better correlates with specific symptoms of excess or deficiency and is an excellent method for monitoring hormone therapy.

Why ZRT Laboratory?

• Ranges adjusted for supplementation — no need to stop hormone supplementation before testing (unlike other labs)
• No sample pooling — each time point is measured individually, not averaged together
• Extraction process — ZRT is the only lab to extract hormones from background contamination in saliva, ensuring accuracy for low-concentration hormones like estradiol
• Industry standards leader — ZRT initiated and manages the Saliva Proficiency Inter-laboratory Testing Program
• Pioneers in saliva testing — one of the first labs to make saliva hormone testing commercially viable worldwide

Learn more: View the ZRT LCMS Provider Data Sheet (PDF)

What’s Normal?

Cortisol production is normally at its highest 30 minutes after waking and declines steadily during the day, reaching its lowest point at bedtime to ensure sound sleep. When this pattern is disrupted by chronic stress, the adrenal glands may produce too much or too little cortisol — leading to fatigue, insomnia, weight changes, and hormonal imbalances.

⚠️ State Restriction — California, Maryland & New York: Due to current state regulations, a doctor’s prescription is required by ZRT Labs to process your sample. We are not authorized to sell this test to individuals in these three states without a prescription. Questions? Call our voicemail line at (520) 877-2637 or contact ZRT Labs directly at (503) 466-1877 or (866) 600-1636.

Cortisol Cx4 Saliva Hormone Test Kit | 4-Point At-Home Collection