These 2 Small Glands Control Your Stress Response—Here’s What You Need to Know

I’d wager that cortisol has cropped up in at least one conversation you’ve had recently. Perhaps a friend has blamed it for her sleepless nights, or you’ve spotted yet another supplement promising to balance it. Either way, cortisol is fast becoming a celebrity villain of the wellbeing world. But here’s something I hadn’t given quite so much thought to until recently: the adrenal glands. I’ll admit, until a women’s health panel discussion put them on my radar, I hadn’t paid them much attention. We’ve become rather accustomed to talking about cortisol, but what about where it actually comes from?

Sitting just above our kidneys, these small glands have surprisingly big jobs on their hands. As well as producing cortisol, they release other hormones that help regulate blood pressure, metabolism and a whole host of essential bodily functions. So, there’s more to our stress response than the hormone that’s been hogging all the headlines.

With so much on our plates already, perhaps it’s time we paid a little more attention to the glands helping our bodies keep up. Because while feeling shattered, wired or permanently on edge might have become something of a personality trait for many of us, that doesn’t mean we should accept it as business as usual.

I spoke with endocrinologists about the role our adrenal glands play, what happens to the body under prolonged stress, and which symptoms are worth paying attention to. We’ll also be separating medical fact from wellness-world fiction, including the much-debated (and rather controversial) concept of adrenal fatigue.

You’ve Heard of Cortisol. Meet the Glands That Make It

First, what are your adrenal glands—and what do they have to do with cortisol?

“Most of us have two adrenal glands, which are small, pyramid-shaped organs sitting directly on top of our kidneys,” explains Dr Anjali Amin, consultant endocrinologist. “Each one is made up of two distinct parts: an outer layer called the cortex and an inner layer known as the medulla.

“The outer layer (cortex) is responsible for producing cortisol, which is important for salt and blood pressure regulation, and small amounts of sex hormones such as testosterone,” explains Amin. The inner layer produces adrenaline and noradrenaline—the hormones responsible for our fight-or-flight response. So, that sudden rush of adrenaline when something frightens you? Thank you, adrenal glands.

But let’s bring things back to cortisol. Made in the outer layer of the adrenals, this hormone has a much bigger job than helping us respond to stress. “Cortisol regulates almost every body function, including metabolism, blood pressure and how the body responds to stress,” says Amin. Quite the workload.

Of course, the adrenal glands don’t operate entirely on their own. “Their cortisol production is controlled by a communication system between the brain and the adrenal glands, known as the hypothalamic-pituitary-adrenal (HPA) axis,” says Amin. A bit of a mouthful, but essentially, it’s the body’s way of making sure cortisol production stays on track. “The hypothalamus in the brain,” continues Amin, “signals the pituitary gland to release a hormone called ACTH. This travels through the bloodstream to the adrenal glands, telling the outer layer (the cortex) to produce cortisol. Once enough cortisol is circulating, a feedback signal tells the brain to ease off production—rather like a thermostat switching off once the room reaches the right temperature.”

In short, your brain issues the instructions, your adrenal glands make the cortisol, and your body has a built-in system to keep the whole operation in check. Teamwork at its best.

What happens to your adrenal glands when you’re under chronic stress?

Cortisol has something of a reputation as the body’s stress villain. The assumption? That constant stress would leave the adrenal glands in overdrive, producing far more cortisol than the body needs. But that’s not quite how it works according to Amin.

“When we’re faced with a short-term stressor, the body’s HPA axis temporarily kicks into action, prompting the adrenal glands to release a little extra cortisol to help us respond. It’s a perfectly normal part of the body’s stress response. But chronic stress is a different story,” says Amin.

Contrary to what some wellness claims might have us believe, prolonged stress doesn’t mean our adrenal glands are endlessly pumping out huge amounts of cortisol, or that they eventually burn out. As Amin explains, chronic stress does not cause your body to spew out huge amounts of cortisol, nor does it cause your adrenal glands to fail.

That’s not to say prolonged stress has no effect. “Rather than sending cortisol levels permanently soaring,” says Amin, “it can disrupt the body’s usual daily rhythm, potentially flattening your body’s morning peak or evening dip.” So the issue isn’t necessarily that your adrenal glands are working overtime; it’s that the body’s carefully choreographed cortisol routine can become less predictable.

It’s a reminder that our stress hormones aren’t quite as straightforward as they might seem. A 2024 review of 12 studies, published in Psychoneuroendocrinology, found no clear link between people’s usual daily cortisol patterns and how much cortisol they released in response to a one-off stressful situation. In other words, there’s more to the story than simply measuring how much cortisol we’re producing.

Low cortisol explained: what happens when your adrenal glands aren’t producing enough? The symptoms to look out for

We’ve talked about what happens when stress affects our cortisol levels, but what about the other side of the coin? What if your body isn’t producing enough?

First, let’s put this into perspective: “Genuine adrenal failure is very rare,” says Niamh Martin, Professor of Endocrinology at Imperial College London. “It can happen when the adrenal glands aren’t working properly, or when the pituitary gland—which sits at the base of the brain—fails to send them the signals they need to produce cortisol.”

When the adrenal glands are the problem, adds Amin, the condition is known as Addison’s disease, an autoimmune condition in which the body’s immune system attacks the adrenal cortex. “This damages the part of the glands responsible for producing cortisol and aldosterone, another hormone that helps regulate salt levels and blood pressure. This is the main cause of adrenal failure in the UK.”

But how would you know if something wasn’t quite right? This is where things get a little more nuanced. “Symptoms such as fatigue and muscle weakness can be associated with adrenal failure, but they’re also incredibly common in people whose adrenal glands are working perfectly well,” explains Martin.

Essentially, feeling exhausted doesn’t automatically mean your cortisol levels are low, and it’s important not to jump to conclusions. That said, there are some tell-tale signs doctors will be looking out for.

The symptoms of adrenal failure to be aware of:

• Severe, persistent fatigue: Tiredness that feels extreme and out of proportion to your usual day-to-day exhaustion.
• Dizziness or low blood pressure: Particularly when standing up, sometimes causing light-headedness or fainting.
• Nausea, tummy pain and unexplained weight loss: You may also notice a reduced appetite.
• Skin darkening: Sometimes described as an unexplained tan, this can be particularly noticeable in skin creases, around the mouth or on areas such as the elbows.
• Salt cravings: This can occur because low aldosterone levels cause the kidneys to lose more sodium than they should.

These signs aren’t exclusive to adrenal failure, so having one or more doesn’t mean you have the condition. If symptoms persist or concern you, speak to your GP, who can arrange further tests if needed.

Adrenal Fatigue: Can Stress Really Exhaust Your Adrenal Glands?

Before we wrap up this adrenal gland deep dive, there’s one rather persistent wellness claim we wanted to get to the bottom of: adrenal fatigue. A quick scroll through TikTok reveals a plethora of videos claiming that stress can leave your adrenal glands exhausted, depleted and desperately in need of a reset. But is there any truth to it?

To Amin, the answer is pretty clear: “Adrenal fatigue isn’t a scientifically recognised medical condition." Chronic stress doesn’t cause your adrenal glands to become tired, worn out or stop producing cortisol. As she puts it, adrenal glands “either work or they don’t.”

A systematic review published in the BMC Endocrine Disorders journal found no scientific evidence to support adrenal fatigue as a genuine medical condition. So, while the term might be popular in wellness circles, it doesn’t have the medical research to back it up.

That’s not to say the symptoms people associate with adrenal fatigue aren’t genuine. “Persistent exhaustion, poor sleep and feeling generally run down are very real experiences, but that doesn’t mean tired adrenal glands are to blame. Poor sleep and shift work, for example, can disrupt the body’s natural cortisol rhythm, while issues such as low iron stores or thyroid disorders can also leave you feeling utterly wiped out,” says Amin.

One final word of caution: Amin advises against spending money on at-home saliva or cortisol testing kits. “Cortisol naturally fluctuates throughout the day, so results without proper clinical context can be misleading—and may cause more worry than they’re worth.”

How to support your adrenal health: three expert tips

First things first: there’s no magic food, supplement or morning routine to directly ‘boost’, detox, or optimise your adrenal glands. As we’ve established, the brain and the adrenal glands work together through a finely tuned, regulated system, so there’s no need to go chasing another complicated wellness protocol. What matters is giving our bodies the care they need to maintain a healthy daily rhythm.

Nutritionist and author of Everything I Know About Cortisol, Hannah Alderson shares five simple places to start:

1. Don’t skip breakfast. Aim for a nourishing mix of protein, healthy fats, and fibre, such as eggs on seeded toast or Greek yoghurt with berries, nuts, and seeds.
2. Think nourishment, not restriction. Fill your plate with colourful plants, wholegrains, quality protein, nuts and oily fish.
3. Be mindful of caffeine. Enjoy your coffee, but try having it after food and keep an eye on how much—and how late—you’re drinking it.
4. Get outside in the morning. Natural daylight, consistent sleep times and a calming evening routine can help support your body’s natural rhythms.
5. Make room for recovery. Walking, gentle movement, socialising and even 10 minutes away from your to-do list can all help.

Ultimately, there’s no need to chase the latest (and ever-evolving) adrenal-boosting trend. Our adrenal glands either work or they don’t; what matters is looking after the body they support.

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