What a cortisol detox can really do for health and weight loss

As we battle the cold, rain, and back-to-work blues this January, we’re looking for anything that will make us feel better. Little wonder the #cortisoldetox trend is gathering pace on social media, fuelling a flurry of adverts for teas and supplements claiming to lower levels of cortisol, the stress hormone that is being blamed for a slew of problems from weight gain to bloating.

Meanwhile, influencers are keen to tell us how to banish “cortisol face” or “cortisol belly”, terms they use to describe the ageing effects of high levels of cortisol on the skin, or weight gain around the abdomen.

But does cortisol really deserve to be demonised?

“Cortisol is a steroid hormone produced by our adrenal glands,” says Dr Nicky Keay, an honorary clinical lecturer in medicine at University College London and author of Hormones, Health and Human Potential.

“Hormones in general are internal chemical messengers that whizz around the bloodstream providing several important functions. While hormones are often viewed as these annoying things that cause us problems, really they’re absolutely vital to our overall health and wellbeing. And cortisol is no exception, playing an important role in regulating our metabolism, blood pressure, blood sugar levels, and immune function, as well as giving us our get up and go.”

The reason for Cortisol’s bad reputation is because it is produced when we experience stress after the hormone adrenaline kicks in. Most of the problems arise when we experience chronic or high levels of stress, which can lead to cortisol spikes (intensive exercise, and poor sleep and diet also cause spikes, says Dr Keay).

Studies show that chronically high cortisol levels can lead to an increased risk of obesity, heart disease, weight gain and depression. One from University College London (UCL) found adults in their fifties who have had long-term exposure to high levels of cortisol were more likely to be overweight.

There are two medical conditions which can be directly pinned to different levels of cortisol, says Dr Keay, but these are rare. “People with Addison’s don’t produce enough cortisol and symptoms include exhaustion. Plus, if they get an infection, they’re very likely to go into septic shock, and they must take steroids to control it. That’s what having very low levels of cortisol looks like.”

The other is Cushing’s disease, also known as hypercortisolism, where the body produces too much. Symptoms include weight gain around the torso and face, relatively skinny arms, thin fragile skin that bruises easily, and muscle weakness. “Conjure up in your mind a picture of Henry VIII with his moon face and large torso,” says Dr Keay, “who along with gout and type diabetes [he] most likely had Cushing’s disease too.”

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She points out that cases of both are rare though. “Most of us sit somewhere in the middle and have a natural cortisol response to stressful situations. Cortisol levels ebb and flow when we need them and tend to peak in the morning giving us the oomph to get out of bed and go about our daily business, which is exactly what you need.”

Stafford Lightman, a professor of medicine at Bristol University who studies the effects of cortisol on the brain and metabolic activity, goes even further and says that almost everything about cortisol detoxes is likely to be untrue. “On social media you have a whole industry of people trying to make out it’s the real reason you’ve got this, or that,” he says. “It’s convenient to blame cortisol for everything.

“But cortisol is a critical hormone. It is secreted in the hours before you wake up, priming your brain for cognitive activities, peaks about 45 minutes after waking, and then slowly decreases throughout the day. It keeps us alert, safe and well. If a double decker bus is coming towards you, you want your cortisol levels to go up because that will help you react quickly and step out of the way.

“It’s also important for your sleep/wake cycle, bones, and muscles. We need to turn the view of cortisol on its head, because it's not cortisol that’s causing your weight gain or poor sleep, it’s what you’re doing.”

Or what you are not doing. This is a view shared by Dr Keay, who says the key isn’t to buy into the idea of lowering your cortisol levels, but rather working to regulate them: “It feels incredibly rude to the millions of years of evolution of hormones to talk about balancing them. They know perfectly well what they’re doing and can regulate themselves, with a little help from us. The imbalance comes from what we do, so we should turn the finger of blame away from cortisol and towards ourselves, and our habits.”

The answer, she says, isn’t found on social media, but rather the ancient Greeks. “Over two thousand years ago, Hippocrates [the Greek physician known as the father of modern medicine] said, ‘If we could give every individual the right amount of nourishment and exercise, not too little and not too much, we would have found the safest way to health’. He's absolutely right but he forgot to mention sleep, which is also crucial.”

Dr Keay says keeping a regular sleep schedule, by going to bed and waking at roughly the same time each day, is key for supporting the natural balance of healthy cortisol levels. Too much stress can disrupt sleep, and a 2024 study published in the health journal Sleep found that pre-bedtime stress is associated with poorer quality and shorter sleep.

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A lack of sleep can also cause us to react more strongly to stressful situations, she says, meaning one cortisol-spiking habit has a trickle-down effect on others. “We know that keeping a regular sleep schedule and being asleep before midnight is good for maintaining our cortisol levels. So, avoid scrolling before bed and establish whatever wind-down routine works for you.

“Another tip is to choose how you respond to stress. The brain’s reaction to any kind of stress, be it a traffic jam or a deadline, will be to chuck some cortisol into your system. The next time you feel your stress levels rising remember that you always have a choice how to react. Tell yourself, ‘This is really annoying, but what can I do?’ If it’s a traffic jam, the answer is nothing. You always have a choice about how you react in situations.”

Dr Keay also recommends finding your equivalent of mindfulness: “I have friends who swear by it. I don’t. But I do love ballet. Find something that works for you, and ideally combine it with some kind of movement because exercise is very good for maintaining the natural levels of cortisol.

“And eat in a sensible way, which means a balanced, nourishing diet. I love my coffee, but I have it in the morning and I don’t have six cups, which has been shown to elevate cortisol levels.”

She also recommends limiting alcohol, which she points out isn’t a relaxant but rather a stressor that disrupts your hormones and leads to poor sleep.

Ultimately, the advice is unless you have a true medical condition, cortisol is unlikely to cause you too many problems, but there are things you can harness your cortisol levels to get the most out of them and tap into their superpower. And while it sounds boring’ says Dr Keay, “the best way to do this is through moderation – and definitely not a so-called cortisol detox."