A cortisol blood test measures the level of cortisol, a hormone made by your adrenal glands that helps regulate stress, metabolism, blood pressure, and immune response. Too much or too little cortisol can signal health issues such as Cushing’s syndrome, Addison’s disease, or problems with adrenal or pituitary function.

Because cortisol affects energy, weight, mood, and how your body responds to stress, testing can provide valuable insights into your overall health and metabolic balance.

This guide explains what it is, how it works, what your results mean, and how you can book a comprehensive blood test to check your Cortisol.

What is Cortisol?

Cortisol is a hormone made by the adrenal glands, which sit on top of your kidneys. It’s often called the “stress hormone” because it rises when your body faces pressure or challenge. Think of cortisol as your body’s built-in alarm system—helping you stay alert, release energy, and respond quickly when needed.

Beyond stress, cortisol also plays a big role in everyday health. It helps control metabolism, balance blood sugar, manage inflammation, and support your sleep–wake cycle. Too much or too little cortisol over time can throw your body off balance and affect your mood, weight, and overall wellbeing.

Quick facts about cortisol:

• Peaks in the morning to give you energy and drops at night to support sleep
• Helps regulate blood pressure, blood sugar, and immune response
• Abnormal levels may signal adrenal, pituitary, or metabolic conditions

In short, cortisol keeps your body running smoothly, but when levels are out of range, it may be a sign of underlying health issues that need attention.

Why is Cortisol important?

Cortisol is central to how your body handles stress, energy, and survival. It’s not just a “stress hormone”—it acts like a thermostat and fuel manager combined: whenever your body senses a challenge (physical or mental), cortisol helps shift resources (glucose, fats, proteins) to where they’re most needed. Over time, though, when cortisol stays high (or too low), it can tip the balance in ways that harm health.

Because cortisol regulates metabolism, immune response, inflammation, blood pressure, and brain function, imbalances are linked to major chronic conditions:

• Elevated cortisol over time is associated with obesity, insulin resistance, type 2 diabetes, high blood pressure, and cardiovascular disease.
• Low cortisol (as in adrenal insufficiency) can lead to fatigue, weight loss, low blood pressure, and immune system problems.

In Australia and globally, stress-driven health burdens are rising, and cortisol dysregulation is believed to play a role in metabolic syndrome and longevity risk.

Understanding and monitoring your cortisol gives you a window into your metabolic health, stress resilience, and long-term wellbeing. It’s not just about “stress”—it’s about how your body balances energy, immunity, and repair.

When should you get a Cortisol test?

A cortisol blood test may be recommended if there are signs your hormone balance is off. Testing is especially important when:

• You have unexplained fatigue, weight changes, muscle weakness, or mood swings
• Symptoms suggest Cushing’s syndrome (high cortisol), such as a round face, easy bruising, or high blood pressure
• Signs point to Addison’s disease (low cortisol), including low blood pressure, dizziness, or salt cravings
• There is a family history of adrenal or pituitary disorders
• You live with chronic conditions such as diabetes, heart disease, or long-term stress-related issues
• Cortisol shifts need monitoring during pregnancy
• Your GP refers you as part of a broader hormone or metabolic health check, which may also include thyroid, glucose, and insulin tests

If you’re dealing with persistent symptoms, a cortisol test can help uncover whether hormone imbalance is affecting your overall health.

How does the Cortisol test work in Australia?

A cortisol blood test in Australia is a simple procedure where a blood sample is taken, usually from a vein in your arm, and sent to a pathology lab for analysis. The test measures cortisol levels at a specific time of day, often in the morning when levels peak. Depending on your doctor’s advice, you may not need to fast, but in some cases, preparation instructions will be given to ensure accurate results.

When it comes to access, your GP can order the test if there are clinical reasons, such as suspected adrenal or pituitary disorders. In many cases, Medicare covers the cost if the test is medically necessary. However, if you’re seeking it as part of a broader health check or without referral, you may need to pay privately. The cortisol test cost in Australia typically ranges from $40 to $80 when ordered outside Medicare coverage.

For a more complete picture, many people choose comprehensive blood test panels that include cortisol alongside other markers like glucose, thyroid, and insulin. This approach provides a wider view of your metabolic and hormonal health.

What do my Cortisol results mean?

Your cortisol test results show how much of this hormone is in your blood at the time of testing. Levels naturally rise and fall throughout the day, so your doctor will consider the timing of your test, your symptoms, and other blood markers before making any conclusions.

Here’s a simple guide to understanding cortisol blood test results in Australia:

It’s important to remember that one result on its own doesn’t always tell the whole story. Your GP may recommend further testing, or checking related markers such as glucose, insulin, or thyroid hormones, to understand the bigger picture of your health.

If your results fall outside the normal range, your doctor will guide you on the next steps, which may include repeat testing, imaging, or specialist referral.

Cortisol in context (other relevant tests)

Cortisol doesn’t work in isolation. To fully understand what your results mean, doctors often look at cortisol levels alongside other markers that affect stress, metabolism, and hormone balance. This gives a clearer picture of how your body is functioning.

For example, thyroid hormones influence energy and metabolism, while glucose and insulin reflect how well your body manages blood sugar under stress. Adrenal and pituitary hormones also interact closely with cortisol, helping regulate the body’s stress response. Looking at these together can reveal whether imbalances are due to cortisol itself or a wider hormonal issue.

Related tests that may be checked with a cortisol test include:

• Thyroid function (TSH, T3, T4)
• Blood sugar and insulin
• Lipid profile (LDL, HDL, triglycerides)

By combining cortisol with these markers, your results become more meaningful and can guide more effective steps to improve your overall health.

Lifestyle and practical steps for Cortisol

Cortisol naturally rises and falls throughout the day, but modern habits like poor sleep, ongoing stress, or an unbalanced diet can keep levels out of sync. While medical care may be needed for significant imbalances, everyday choices can also play a role in supporting healthy cortisol regulation.

Here are six practical steps that may help:

1. Balanced nutrition: Eat whole grains, lean proteins, healthy fats, and plenty of fruits and vegetables to stabilise blood sugar and avoid unnecessary cortisol spikes.
2. Limit stimulants: Reduce caffeine, alcohol, and processed foods that can overstimulate the stress response or disrupt sleep.
3. Quality sleep: Aim for 7–9 hours nightly, keeping a consistent routine to support your natural cortisol rhythm.
4. Stress management: Use mindfulness, meditation, or deep breathing to ease daily pressures and lower prolonged cortisol elevation.
5. Regular exercise: Gentle activities like walking, yoga, or swimming help regulate stress hormones, while strength training supports long-term resilience.
6. Healthy routines: Take regular breaks, spend time outdoors, and stay connected socially, all of which help buffer the body’s stress response.

By building these habits into your lifestyle, you can improve energy, mood, and overall wellbeing. The best starting point is testing. Once you know your levels, you can take personalised steps.

FAQs about Cortisol blood test in Australia

How much does a cortisol blood test cost in Australia?

The cortisol blood test cost in Australia usually ranges from $40 to $80 if paid privately. If ordered by a GP for medical reasons, it may be covered by Medicare.

Is a GP referral needed for a cortisol test?

Yes, in most cases a GP referral is required. This ensures the test is clinically appropriate and may allow Medicare to cover the cost.

Does Medicare cover cortisol testing?

Medicare typically covers a cortisol test if your doctor orders it for medical reasons, such as suspected adrenal or pituitary disorders.

Can you get a cortisol test during pregnancy?

Yes. Cortisol naturally increases during pregnancy, but your doctor may order a test if there are concerns about hormone imbalance or adrenal health.

What symptoms suggest I might need a cortisol test?

Symptoms include unexplained fatigue, weight changes, muscle weakness, mood swings, high or low blood pressure, and dizziness.

What is the normal range for cortisol levels?

In Australia, the typical reference range is 145–619 nmol/L (morning sample). Results outside this range may need further investigation.

Can a cortisol test be part of a broader health check?

Yes. Cortisol is often included in comprehensive hormone and metabolic panels alongside thyroid, glucose, and insulin tests.

Conclusion

Cortisol is a vital hormone that helps regulate stress, metabolism, energy, and immune function. When levels are too high or too low, it can affect everything from mood and weight to blood pressure and long-term health risks. A simple cortisol blood test can provide valuable insight into how your body is managing stress and whether there may be underlying adrenal or pituitary concerns.

Understanding your cortisol levels is more than just checking a number—it’s a way to better understand your body and take proactive steps toward improving wellbeing. With the right information, you can make changes that support balance, energy, and resilience over the long term.

Take control of your health today. Sign up for our comprehensive blood test and get clear insights into your cortisol and more than 50 other key markers.

References

• Healthdirect Australia — The role of cortisol in the body
• Better Health Victoria — Hormones: cortisol and corticosteroids
• Bornstein SR et al. Diagnosis and Treatment of Primary Adrenal Insufficiency (Endocrine Society guideline, J Clin Endocrinol Metab, 2016)
• Pathology Tests Explained — “Cortisol” test details (Australia)
• NC­BI / Endotext — Adrenal Insufficiency overview