Cortisol Test🧪 Cortisol Test
Measures the body’s stress hormone to assess adrenal function and energy regulation.
🔍 What is it?
A Cortisol test measures the level of cortisol in your blood, saliva, or urine. Cortisol is a hormone produced by your adrenal glands and plays a vital role in your body’s stress response, metabolism, blood pressure, and immune function.
Imbalances can lead to symptoms like chronic fatigue, weight changes, mood swings, and poor stress tolerance.
📊 What does it measure?
| Marker | What It Indicates |
| Cortisol (morning blood or saliva sample) | Measures your adrenal gland function and daily cortisol rhythm |
| 24-hour urinary cortisol | Assesses total cortisol production over a day |
| ACTH stimulation test (in some cases) | Evaluates adrenal gland response in suspected adrenal insufficiency |
❓ Why might I need it?
You may need a cortisol test if you experience:
- 😩 Experience chronic tiredness or burnout
- ⚖️ Have unexplained weight gain or loss
- 🩸 Suffer from low blood pressure or dizziness
- 📈 Have high blood pressure or blood sugar issues
- 😟 Struggle with anxiety, irritability, or depression
- 😴 Have poor sleep or trouble waking up in the morning
- 🧬 Are being checked for adrenal conditions (like Cushing’s syndrome or Addison’s disease)
🧬 Conditions it can help detect:
- Cushing’s syndrome – Excess cortisol
- Addison’s disease – Insufficient cortisol
- Adrenal fatigue (non-NHS recognised, but commonly tested privately)
- Pituitary disorders affecting hormone regulation
- Stress-related health issues (used alongside other markers)
📈 Typical Reference Ranges (may vary by lab):
| Sample Time | Expected Cortisol Level |
| 8–9 AM (blood) | 130–690 nmol/L |
| Late PM | Typically lower due to diurnal rhythm |
Cortisol levels naturally follow a daily cycle, peaking in the early morning and falling by night. This is why the timing of your test matters.
⏱️ How is it done?
- Blood or saliva sample (often done in the early morning)
- May be combined with stimulation/suppression tests
- Results available in 1–2 working days
💷 Typical Private Cost in the UK:
- Cortisol (blood or saliva test): £40–£80
- Often included in fatigue, stress, or hormone imbalance panels
✅ Commonly combined with:
- Thyroid function tests – For fatigue or metabolic concerns
- Vitamin B12 & Iron studies – For energy-related symptoms
- DHEA & other adrenal hormones – In extended hormone panels
- Glucose tests (HbA1c) – To assess metabolic impact of stress
📚 References:
- NHS UK – Addison’s disease diagnosis and testing
- National Institutes of Health (NIH) – Cortisol test
- Patient.info – Adrenal Insufficiency and Addison’s Disease