Test ID: S-120 | Sample Type: Saliva | Technology: LC-MS/MS | Results Time: 3–5 Working Days After Laboratory Receives Sample | Laboratory: ZRT Laboratory – CLIA Certified | Hormone Specialist Doctor Interpretation: Included | Suitable For: Adults and Children
What Does This Test Measure?
Saliva — 4-Point Cortisol Profile (LC-MS/MS): Morning Cortisol, Noon Cortisol, Evening Cortisol, Night Cortisol.
4 markers — the complete daily adrenal rhythm for assessing the full cortisol curve, HPA axis function, and cortisol–sex hormone interaction across the entire day in a single at-home saliva kit.
Related Symptoms
Persistent fatigue or exhaustion that sleep does not resolve, difficulty waking or feeling unrefreshed in the morning, afternoon energy crashes or reliance on caffeine, insomnia or night waking, racing thoughts at bedtime, anxiety or emotional overwhelm, PMS that has worsened particularly in the luteal phase, irregular or missed periods, perimenopausal or menopausal symptoms including night sweats, unexplained abdominal weight gain, brain fog, low libido, burnout, PCOS, or thyroid symptoms.
Did You Know?
In women, cortisol and progesterone share the same hormonal precursor — pregnenolone. Under chronic stress, the body prioritises cortisol at the direct expense of progesterone synthesis, producing the most common hormonal pattern in stressed women: oestrogen dominance with low progesterone, worsening PMS, cycle irregularity, and anxiety — even when estradiol is within the reference range. Elevated evening and night cortisol are the most clinically significant patterns for women: evening cortisol prevents the progesterone and melatonin rise needed for restful sleep, while night cortisol is the primary driver of insomnia and night sweats in perimenopause. Neither pattern is detectable from a morning reading alone.
Who Should Consider This Test?
- Persistent fatigue or exhaustion that sleep does not resolve
- Difficulty waking in the morning or feeling unrefreshed despite adequate sleep
- Afternoon energy crashes or heavy reliance on caffeine to function
- Insomnia, night waking, or racing thoughts at bedtime
- Anxiety, irritability, or emotional overwhelm
- PMS that has worsened, particularly mood symptoms in the luteal phase
- Irregular, heavy, or missed menstrual cycles
- Perimenopausal or menopausal symptoms including night sweats and hot flushes
- Unexplained weight gain, particularly around the abdomen
- Sugar or salt cravings, particularly in the afternoon
- Brain fog, poor memory, or difficulty concentrating
- Low libido or reduced motivation
- Chronic stress or burnout
- PCOS, thyroid conditions, or known hormonal imbalance
- Women on HRT wanting to understand whether cortisol is driving residual or breakthrough symptoms
Why This Test Is Particularly Important for Women
- Morning cortisol sets the hormonal tone for the entire day in women — a blunted Cortisol Awakening Response is associated with burnout, fatigue severity, and disrupted cycle regularity; an exaggerated response drives anxiety, heart palpitations, and acute progesterone suppression
- Elevated noon and evening cortisol suppress progesterone synthesis via pregnenolone steal throughout the day — producing oestrogen dominance, worsening PMS, luteal phase defect, and cycle irregularity even when absolute estradiol appears normal
- High evening cortisol prevents the natural progesterone and melatonin rise in early evening — directly impairing sleep onset, sleep quality, and the hormonal restoration that occurs during the first sleep cycles
- Elevated night cortisol is the primary driver of insomnia and night sweats in perimenopause — a pattern frequently attributed to oestrogen deficiency alone but driven or compounded by cortisol dysregulation that HRT cannot address
- A flat cortisol curve — seen in advanced burnout — produces profound exhaustion, emotional numbness, and immune suppression that is clinically distinct from elevated-curve patterns and requires a different intervention; the two are indistinguishable from symptoms alone
Not Sure Which Test Is Right for You?
Email us at info@hormonelab.co.uk with your gender, age, symptoms, medications, and any current treatments. We will forward your enquiry to our doctors and respond within 24 hours.
How It Works
- Order your kit — delivered directly to your door
- Collect saliva at four time points: morning (within 30 minutes of waking, before 9am), noon, evening, and night — following the detailed instructions provided
- Post your samples to ZRT Laboratory using the return instructions provided
- Receive your full report by email within 3–5 working days
What You Receive
- All four cortisol readings with female-specific reference ranges
- Visual chart showing your complete daily cortisol rhythm curve
- Written interpretation by a Hormone Specialist PhD Doctor including cortisol–progesterone interaction, cycle impact, and phase-specific hormonal consequences
- Personalised next-step recommendations
- Laboratory fee included — no hidden charges
Why We Use ZRT Laboratory
All testing is performed by ZRT Laboratory — a globally recognised, CLIA-certified diagnostic laboratory founded in 1998 by Dr. David Zava, PhD. ZRT has performed over 11 million tests and is trusted by healthcare professionals in 96+ countries.
- Pioneers of at-home dried blood spot (DBS) and saliva hormone testing
- Advanced LC-MS/MS technology for clinical-grade accuracy
- Qualified for the CDC Hormone Standardization (HoSt) Program
- Personalised reference ranges based on age and sex
Through our partnership with ZRT Laboratory, Hormone Lab UK delivers internationally recognised, research-backed hormone testing to people across the UK and Europe — from the comfort of home.
Frequently Asked Questions
Why measure cortisol at four points rather than just the morning?
Each time point has distinct hormonal consequences for women. Morning cortisol assesses the Cortisol Awakening Response and progesterone suppression risk; noon assesses mid-day stress impact on cycle regularity; evening assesses whether cortisol is preventing the progesterone and melatonin rise needed for sleep; night assesses whether cortisol is driving insomnia or night sweats. A single reading cannot identify which phase is responsible for a woman’s symptoms.
When should I collect my samples during my menstrual cycle?
This test can be taken at any point in your cycle. Guidance on optimal timing is included in your kit instructions.
Can I use this test if I am on HRT, the contraceptive pill, or other hormonal medication?
Yes. This test is suitable for women on HRT, the contraceptive pill, or other hormonal medications. It is particularly valuable for identifying whether cortisol dysregulation is driving residual or breakthrough symptoms that hormone therapy is not addressing.
Should I start with just the morning cortisol test instead?
The morning test (SAL-CORT-AM-F) is an appropriate starting point if your symptoms are primarily morning-focused. If you have symptoms across different parts of the day — afternoon crashes, evening anxiety, or night waking — the 4-point profile is the more appropriate assessment and avoids the need for a second test.
Does the price include the laboratory fee?
Yes. The full laboratory analysis fee is included. There are no additional charges. You are only responsible for posting your samples to the laboratory.
How long is the kit valid for?
The kit must be used within 12 months of the purchase date.
