The Wonder of Cortisol: Friend, Foe or Just Misunderstood?

Let’s talk about cortisol. Yes, that hormone that tends to get a bad rap, blamed for everything from belly fat to burnout. But like most things in the body, cortisol isn't inherently bad.

In fact, it’s rather wonderful when it’s doing its job properly. The problem arises when it gets stuck in overdrive, or takes a prolonged holiday.

So, let’s dig into what cortisol actually is, how it should work, what happens when it goes rogue, and what you can do to support it (without having to move to a yoga retreat in Bali).

Cortisol 101: What Is It?

Cortisol is a steroid hormone made by your adrenal glands, those two little hat-shaped glands that sit on top of your kidneys. It’s often called the “stress hormone,” but it’s so much more than that.

Think of cortisol as your body's internal project manager, helping you wake up, respond to stress, regulate blood sugar, manage inflammation, and even control blood pressure.

It works on a rhythm, known as your circadian rhythm. Ideally, cortisol peaks in the morning to help you wake up and face the day (hello, motivation!), then gradually tapers off so that melatonin can take the night shift and help you sleep.

Cortisol’s Many Hats: What It Does

Regulates your stress response. Cortisol helps you deal with danger. Back in the day, that meant an acute stressor like trying to outrun a sabre-toothed tiger. Today, it's more likely to be less acute but more volume of stressors like an overflowing inbox, train running late, horrible traffic and/or a toddler with a marker pen and no boundaries.

Supports energy production. It helps maintain steady blood sugar levels by nudging the liver to release glucose, keeping your brain and muscles fuelled.

Reduces inflammation. In short bursts, cortisol acts like the body’s own anti-inflammatory. Chronic levels, though, do the opposite.

Balances blood pressure. It keeps your blood vessels responsive, which is vital when you suddenly stand up or need to respond to physical stress.

Impacts your immune system. Too much or too little cortisol can mess with your body’s ability to fight off bugs.

When Cortisol Loses Its Rhythm

Sometimes cortisol stops being your project manager and starts acting like an over-caffeinated boss who emails you at 3 a.m.

Too much cortisol (for too long) can lead to:

• Sleep problems (tired but wired)

• Sugar cravings

• Weight gain (especially around the middle)

• Anxiety or feeling on edge

• Hormonal imbalances (it can hijack your sex hormones, more on that below)

• Gut issues like bloating, constipation, or diarrhoea

• Suppressed immune function (hello, endless colds)

Too little cortisol (aka burnout or HPA axis dysregulation) might leave you feeling:

• Constantly exhausted, even after sleep

• Dizzy or lightheaded

• Craving salt

• Struggling to get going in the morning

• Flat or emotionally ‘numb’

The Cortisol–Hormone–Gut Triangle: A Delicate Dance

Cortisol & Hormones

When your body perceives stress, it prioritises survival over reproduction. That means cortisol can ‘steal’ resources from other hormones like progesterone or DHEA, leading to imbalances that affect menstrual cycles, fertility, mood, and more. For example, low progesterone can show up as PMS, anxiety, or sleep problems.

Cortisol also messes with blood sugar regulation, which can drive insulin resistance, further complicating hormonal balance.

Cortisol & Gut Health

Your gut and brain are in constant communication. This is often called the gut–brain axis, and cortisol is a key part of that conversation. Too much cortisol can:

• Disrupt digestion and reduce stomach acid

• Increase intestinal permeability (hello, “leaky gut”)

• Alter your microbiome, favouring the growth of less helpful bacteria

• Affect motility (leading to bloating, constipation, or the runs)

Myth Busting: Let’s Set the Record Straight

“Cortisol is bad!”

Nope. It’s vital. It only becomes a problem when it's out of balance, like most things in life.

“You can fix cortisol overnight.”

Sadly not. It's a long game. Supporting your stress response takes consistency.

“If you're tired, your cortisol must be low.”

Not always. You can feel tired with high cortisol too, especially if it’s spiking at the wrong time of day (like bedtime!).

“Adrenal Fatigue”: Fact or Fiction?

The term “adrenal fatigue” has become popular in wellness circles to describe the feeling of being constantly exhausted, burnt out, and unable to cope with stress. While the symptoms people describe are very real, the term itself isn’t recognised in mainstream medical literature.

The idea behind adrenal fatigue is that after prolonged stress, your adrenal glands become "tired" and stop producing enough cortisol. However, research shows that in most cases, the adrenals themselves are still functioning, they’re just following orders from higher up the chain, namely the brain and the HPA (hypothalamic–pituitary–adrenal) axis.

So, while your adrenals aren’t actually burnt out (no tiny adrenal-sized armchairs needed), your stress response system might be dysregulated. This is often called HPA axis dysfunction, which is a more accurate (if less catchy) way of describing what’s going on.

In practice, the symptoms are the same; fatigue, sleep issues, hormonal imbalances, low resilience to stress, but understanding the mechanism helps us support it more effectively.

How You Can Support Healthy Cortisol Levels

Dietary Tips: Feed, Don't Fight, Your Adrenals

Balance your blood sugar: Every meal should include protein, healthy fats, and fibre-rich carbs. This keeps energy steady and reduces cortisol spikes.

Don’t skip meals, especially breakfast. Your adrenals love routine.

Eat magnesium-rich foods: Think leafy greens, nuts, seeds, and whole grains—magnesium helps calm the nervous system.

Limit (or remove) caffeine: Especially if you feel jittery or anxious. Swap that third coffee for a herbal tea and aim to move to decaffeinated options after 12pm.

Reduce ultra-processed foods: These can be inflammatory and destabilise blood sugar.

Hydrate: Dehydration is a sneaky stressor. Aim for around 1.5–2 litres of water daily (herbal teas count!).

Lifestyle Tips: Calm the Chaos

Prioritise sleep: Aim for 7–9 hours. Keep lights dim in the evening, use blue light filters or glasses and avoid screens late at night.

Get morning light exposure: It helps regulate your cortisol rhythm.

Move your body, but don’t overdo it. Overtraining can raise cortisol. Try moderate exercise, walking, Pilates, yoga, or dancing around your kitchen.

Breathe: Box breathing, meditation, or just pausing for a few deep belly breaths can help calm the stress response.

Reduce screen overload: Constant notifications = constant stimulation. Your nervous system needs a break.

Laugh and connect: Time with loved ones (furry ones included!) can lower cortisol naturally.

Final Thoughts

Cortisol isn’t out to get you, it’s just trying to keep you safe. The problem is that modern life gives it no rest. Chronic stress, sugar-laden diets, over-caffeination, poor sleep, and never-ending notifications keep it buzzing when it should be resting.

The good news? Your body is incredibly responsive to support. Small, consistent shifts in your diet and lifestyle can make a big difference. And if your hormones or gut are already out of balance, addressing cortisol might just be the missing piece of the puzzle.

Want personalised support to balance your cortisol, restore your energy, and feel like yourself again? Let’s chat (click here to book)