Test ID: S-122
The Female Cortisol Awakening Response (CAR) Test (LCMS) is the most detailed at-home adrenal function test available for women, measuring cortisol at six precise time points throughout the day — including three readings in the critical waking window — plus DHEAS. Together, these markers provide a complete picture of how your HPA axis activates in the morning, sustains energy through the day, and winds down at night.
The Cortisol Awakening Response is one of the most clinically informative hormonal patterns in women’s health research. It is uniquely disrupted by the hormonal changes of the menstrual cycle, perimenopause, chronic stress, and burnout — and its dysfunction is strongly linked to PMS, fatigue, mood disorders, sleep problems, and worsening menopausal symptoms. This test gives you the granular evidence to understand exactly where your cortisol rhythm is breaking down and why.
Test from home with confidence — no clinic visit required.
What Is the Cortisol Awakening Response (CAR) and Why Does It Matter for Women?
In a healthy pattern, cortisol rises by approximately 50% within the first 30 minutes of waking — a surge that prepares the brain and body for the demands of the day. This is the Cortisol Awakening Response. It then continues to decline gradually until it reaches its lowest point at night, supporting melatonin production and restorative sleep.
In women, this rhythm is directly modulated by oestrogen and progesterone — meaning it shifts across the menstrual cycle, worsens during perimenopause, and is profoundly affected by chronic stress:
- A blunted or flat CAR — the most common pattern in burnout and adrenal fatigue; associated with profound morning exhaustion, inability to get going, emotional flatness, and immune suppression in women
- An exaggerated CAR — associated with anxiety, heart palpitations on waking, high perceived stress, and premenstrual mood worsening; common in women with high-demand lifestyles or trauma history
- Elevated evening or night cortisol — prevents progesterone and melatonin from rising, causing insomnia, racing thoughts, night sweats, and PMS mood symptoms in the luteal phase
- Low DHEAS alongside cortisol dysregulation — signals adrenal exhaustion and depleted oestrogen and testosterone precursor supply; strongly linked to worsening perimenopause symptoms, low libido, and accelerated ageing
What This Test Measures
Cortisol — 6 Time Points
- Cortisol Upon Waking (within 5 minutes) — your baseline adrenal output on waking
- Cortisol +30 Minutes After Waking — the peak of the Cortisol Awakening Response; should be approximately 50% higher than the waking value in healthy adrenal function
- Cortisol +60 Minutes After Waking — the start of the decline; assesses how quickly the CAR resolves and adrenal regulation quality
- Midday Cortisol — assesses sustained stress response and energy maintenance; elevated midday cortisol in women is linked to blood sugar instability, anxiety, and luteal phase worsening
- Evening Cortisol — should be declining significantly; elevated evening cortisol in women blocks progesterone and melatonin, disrupting sleep and hormonal restoration
- Night Cortisol — should be at its lowest; elevated night cortisol is a primary driver of insomnia, racing thoughts, and night sweats — particularly in perimenopause and menopause
DHEAS (Dehydroepiandrosterone Sulfate)
The adrenal precursor to oestrogen and testosterone in women. DHEAS reflects total adrenal reserve and long-term stress burden. Low DHEAS is associated with persistent fatigue, low libido, poor stress resilience, worsening perimenopause symptoms, and accelerated hormonal ageing. It declines naturally from the mid-30s but can fall much faster under chronic stress or burnout.
- How and when to collect your saliva samples: Saliva Testing Instructions
- Click to see >> Sample Saliva Test Result Report
Who Should Consider This Test?
This test is particularly relevant for women who experience:
- Waking exhausted despite adequate sleep — unable to get going in the morning
- Anxiety, heart palpitations, or a sense of dread on waking
- Persistent fatigue that does not respond to rest
- Insomnia, night waking, or racing thoughts at bedtime
- PMS that has worsened — particularly mood symptoms, anxiety, and irritability in the luteal phase
- Irregular, heavy, or missed periods
- Perimenopausal or menopausal symptoms including hot flushes, night sweats, and low mood
- Chronic stress, burnout, or emotional exhaustion
- Low libido or reduced motivation
- Brain fog, poor concentration, or memory issues
- Unexplained weight gain, particularly around the abdomen
- Sugar or salt cravings, especially in the afternoon
- Low blood pressure or dizziness on standing
- PCOS, thyroid conditions, or known hormonal imbalance
- Frequent illness or poor recovery
- Suspected adrenal fatigue or HPA axis dysfunction
Why Choose Saliva Testing for the CAR?
- Measures bioavailable (active) cortisol — the fraction actually affecting your cells
- Avoids the stress-induced cortisol spike triggered by a blood draw — which would distort the waking readings most critical to CAR assessment
- Allows precise at-home collection at the exact waking time points required
- Captures the full morning awakening curve that clinic-based testing cannot replicate
6-Point Collection Protocol
- Sample 1: Within 5 minutes of waking — before getting out of bed
- Sample 2: 30 minutes after waking
- Sample 3: 60 minutes after waking
- Sample 4: Midday
- Sample 5: Evening
- Sample 6: Night (before sleep)
Full collection instructions and guidance on optimal cycle timing are included in the kit.
Key Features
- 6-point cortisol measurement plus DHEAS — the most detailed adrenal profile available at home
- At-home saliva collection — no needles, no clinic visits
- Results within 3–5 working days after lab receipt
- Expert analysis by a Hormone Specialist PhD Doctor
- Full diurnal cortisol curve with graphical and numerical results
- All-inclusive price — laboratory fees included, no hidden costs
- Valid for 12 months from purchase
What Your Report Includes
- All six cortisol readings and DHEAS with reference ranges
- Full diurnal cortisol curve graph including the CAR window
- Explanation of your CAR pattern and what it means for your hormonal and adrenal health as a woman
- Specialist commentary by a Hormone Specialist PhD Doctor
- Practical next-step recommendations
Frequently Asked Questions
What hormones are included?
Cortisol at six time points (waking, +30 min, +60 min, midday, evening, night) and DHEAS.
Why is the CAR particularly important for women?
The CAR is directly modulated by oestrogen and progesterone and shifts across the menstrual cycle and menopause transition. Disrupted CAR patterns in women are strongly linked to PMS, perimenopause symptoms, chronic fatigue, and mood disorders — often before any other hormonal abnormality is detectable.
When should I collect my samples during my cycle?
This test can be taken at any point in your cycle. Guidance on optimal timing is included in the kit.
Can I use this test if I am on HRT, the contraceptive pill, or other hormonal medication?
Yes. If you are on hormone or cortisol-related medication, it is advisable to inform your healthcare provider. Results will be interpreted in the context of your health history.
Do I need to fast?
No fasting required. Follow the timing instructions carefully — particularly for the three morning samples, which must be collected at exact intervals after waking.
Are there hidden costs?
No. Laboratory analysis and specialist review are fully included in the price.
How long until I receive results?
3–5 working days after lab receipt.
How long is the kit valid?
12 months from purchase.
Who pays for shipping to the lab?
You are responsible for posting your samples to the laboratory. Clear instructions are included in your kit.
Why We Partner with ZRT Laboratory
At Hormone Lab UK, every home test kit is analysed by ZRT Laboratory, a globally recognised, CLIA-certified diagnostic and research laboratory specialising in hormone testing, thyroid testing, fertility testing, adrenal function, neurotransmitter analysis, cardiometabolic health, heavy metals, and wellness testing. Founded in 1998 by renowned biochemist and breast cancer researcher Dr. David Zava, PhD, ZRT has become one of the world’s leading laboratories for advanced functional health testing.
With more than 11 million laboratory tests performed and healthcare professionals in over 96 countries relying on its expertise, ZRT is recognised for scientific excellence, analytical accuracy, and continuous innovation. The laboratory pioneered at-home saliva hormone testing, introduced the first commercially available dried blood spot (DBS) hormone tests, and developed Dried Urine Testing (DUTS), helping make advanced laboratory diagnostics more accessible and clinically meaningful.
Every sample is analysed using state-of-the-art LC-MS/MS and ICP-MS technology under rigorous quality control standards. ZRT collaborates with the CDC, NIH, and leading universities, supporting ongoing research and advances in laboratory medicine.
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