Cortisol: What It Is and Why It Matters for Your Health (and why getting a blood test is basically pointless)

Firstly, What is Cortisol?

Cortisol is a hormone produced by your adrenal glands (small glands that sit on top of your kidneys). It plays a key role in helping your body:

• Respond to stress

• Regulate metabolism

• Control inflammation

• Support your sleep-wake cycle

• Manage blood pressure and blood sugar

In small doses, cortisol is essential for energy, focus, and even motivation. The problem? Many of us are producing too much of it, for too long.

It’s totally valid to want answers when you're feeling fatigued, wired, or "off" - and cortisol often comes up in that conversation. But here's the thing:

Measuring cortisol through a single blood test isn't always accurate or helpful.
Here’s why:

1. Cortisol is constantly changing

Cortisol follows a natural rhythm—high in the morning and gradually lowering through the day. A single blood test gives just a snapshot, not the full picture.

You could have “normal” levels on paper but still be experiencing symptoms related to cortisol dysregulation.

2. The testing method can spike it

Getting blood drawn - especially if you’re anxious or rushed - can actually cause a short-term cortisol spike. That means your results may reflect stress from the needle, not your everyday baseline.

3. It doesn’t show patterns over time

Cortisol issues are often about chronic dysregulation, not just high or low levels at one point. What’s more important is how your cortisol behaves across the day - which blood testing doesn’t capture.

What works better?

If cortisol testing is truly needed, saliva or urine tests taken at multiple points during the day (morning, noon, afternoon, night) give a more accurate look at your daily cortisol rhythm.

But often, your symptoms and lifestyle patterns are more helpful than lab numbers.

Bottom line?

Cortisol isn’t the bad guy—it’s just a hormone trying to help you survive. But in today’s fast-paced world, our bodies are often stuck in “on” mode. By learning how to recognise and reduce the everyday stressors that affect your cortisol levels, you’re not just managing stress—you’re building a more sustainable, supportive foundation for your health.

Also…you don’t always need a test to know that your body is under stress. If you're feeling exhausted, overstimulated, or stuck in survival mode, that’s worth listening to - even if your bloods say you're "fine."

The information in this article is intended for general education purposes only and is not a substitute for personalised medical or dietary advice. Always consult with your doctor, dietitian, or qualified health professional before making any changes to your health or nutrition plan.