Cortisol responds to sleep, physical activity and meditation, and it does not respond to any supplement sold to lower it. That is most of the useful answer, and the rest of this article is about why the internet’s version is so much more complicated than the evidence.
The complication is commercial. “Lower your cortisol” is one of the most profitable phrases in wellness, and the market attached to it rests on a condition that does not exist.
What cortisol actually does
Cortisol is a hormone that mobilises energy and regulates inflammation, and you would die without it. Treating it as a toxin to be minimised gets the biology backwards before any advice is given.
It runs on a daily rhythm. Levels rise steeply in the half hour after waking, which is the cortisol awakening response and is what gets you out of bed, then fall across the day to a low around midnight. That swing is large, which is the reason a single reading without a time attached tells you very little.
The problem in chronic stress is not the hormone. It is the pattern: a system that activates repeatedly and never fully stands down, so the rhythm flattens and the recovery periods that make the response useful stop happening.
Adrenal fatigue is not a condition
Adrenal fatigue is not recognised by any endocrinology society, and a systematic review of 58 studies found no evidence for it. [cadegiani-2016-adrenal-fatigue] That matters commercially, because it is the premise almost every cortisol supplement is sold on.
The claim is that prolonged stress exhausts the adrenal glands until they cannot produce enough cortisol, producing tiredness, brain fog and weight gain. The review examined the tests used to support it and found them inconsistent and unable to distinguish people said to have the condition from people who do not.
There is a real condition in the neighbourhood, and confusing the two is the danger rather than the wasted money. Adrenal insufficiency, including Addison disease, is a genuine and potentially life-threatening disorder with a specific diagnostic test. Someone who accepts an adrenal fatigue explanation and buys a supplement is someone who has stopped looking, and the things that actually produce those symptoms, thyroid disease, anaemia, sleep apnoea and depression among them, are all treatable and all missed by that route.
What the evidence supports
Three things have real evidence behind them, and none of them is purchasable.
Meditation. A meta-analysis found meditation reduced cortisol, systolic blood pressure and heart rate. [pascoe-2017-meditation-cortisol] The detail that makes it worth citing is the comparison it used: it was restricted to trials with an active control group, so the finding is not simply the difference between doing something and doing nothing, which is the weakness most meditation research has.
Sleep. Short and disrupted sleep raises evening cortisol. This runs in both directions, which is why the loop is difficult to break from the middle: raised cortisol at night makes sleep worse, and worse sleep raises it further. Fixing sleep first is not an arbitrary starting point, it is the intervention with the most downstream effect.
Movement, at the right dose. Regular moderate activity is associated with lower resting cortisol over weeks. A single hard session raises it acutely, which is normal and not a problem, unless intense training is being added on top of an already depleted period without the recovery that converts it into a benefit.
A schematic summary of how well supported each claim is, based on the sources cited in this article. Not measured data, and not a ranking of how much any one thing will help you.
What about ashwagandha
Ashwagandha has small trials suggesting an effect on cortisol, and it is the one ingredient in this market with anything behind it at all. That is a much weaker statement than the marketing makes it sound.
The trials are typically short, small, and frequently funded by the companies selling the product. It is also not risk free: cases of liver injury have been reported, and it interacts with thyroid medication and sedatives. It is not recommended in pregnancy.
If you want to try it, that is a decision to make with a pharmacist or GP who knows what else you take, rather than on the strength of a product page. It is not a substitute for sleep.
The tests, and why not to order one
A single blood cortisol result is close to uninterpretable without knowing the time it was taken, and home saliva panels sold direct to consumers are not the tests used to investigate adrenal disease.
Genuine investigation uses specific protocols, and a doctor orders them after examining you and hearing the history. Cushing syndrome, the condition of genuinely high cortisol, has a recognisable picture: weight gain concentrated on the trunk and face, purple stretch marks, easy bruising, weakness in the thigh and shoulder muscles, raised blood pressure and blood sugar. It is rare, and it does not present as feeling tired and puffy.
The symptoms marketed as high cortisol are the least specific symptoms in medicine. That is what makes them good marketing and useless diagnosis.
Is it worth seeing a doctor rather than buying something?
Tick anything true. This is a reflection prompt rather than a test, and it produces no diagnosis.
0 of 7 ticked
Several of these have specific, treatable explanations that a supplement cannot address and a blood test can find. Describe the symptoms and how long they have lasted, and ask for the ordinary tests rather than a cortisol panel.
One of these is enough to mention at a routine appointment. If it was the supplement item you ticked, that is the pattern this article is about rather than a symptom.
Nothing here stands out medically. If the underlying question is how much pressure you are actually under, the stress screener below is a more useful measure than any hormone reading.
What to actually do this week
None of this is exciting, which is precisely why it does not sell.
- Fix the wake time before the bedtime. A consistent wake time anchors the rhythm cortisol runs on, and it is the half of sleep advice you can actually enforce.
- Walk rather than train. If you are depleted, low-intensity movement does more than a session that adds another demand.
- Ten minutes of something meditative. The trials that measured an effect used ordinary practices, not long retreats. Our guide to mindfulness for overthinking covers where to start.
- Look at alcohol honestly. It lowers tension for about two hours and then fragments sleep, which raises everything this article is about.
- Change the demand, not just the response. The standard measure of stress is built from control, predictability and recovery, and the interventions with lasting effect move one of those three. [cohen-1983-pss-cortisol] Our guide to what stress is and what reduces it covers that.
When to seek help
See a GP if fatigue has lasted more than a few weeks, if your weight has changed without explanation, if you bruise easily or notice muscle weakness, or if you feel faint on standing. Those have specific tests and several have specific treatments.
Go sooner if you have been putting off an appointment because you found an explanation online. That delay is the actual risk in this topic, and it is more common than either of the conditions involved.
Go urgently if you have thoughts of harming yourself. In the UK, Samaritans is free on 116 123 at any hour.
How MyFreud can help
The question worth answering is whether your symptoms track the pressure you are under or ignore it, and memory is bad at that. MyFreud gives you daily mood tracking that shows the pattern across weeks, so you can see whether a hard fortnight moved the line before you spend anything on a supplement.
Download MyFreud and start today: App Store or Google Play.