The short version
- - Cortisol is a steroid hormone made by the adrenal glands. Its everyday jobs include regulating blood sugar, blood pressure, metabolism and the sleep-wake cycle, as well as helping the body respond to stress (Society for Endocrinology).
- - Cortisol follows a 24-hour rhythm: it rises around waking, generally declines across the day and reaches its lowest levels during the night.
- - A 2017 meta-analysis of 80 studies found that flatter daily cortisol slopes were associated with poorer mental and physical health outcomes (Adam et al., Psychoneuroendocrinology).
- - The aim is not a low cortisol number. In healthy physiology, cortisol is higher around waking and lower at night.
- - 'Cortisol face' and 'cortisol belly' borrow the signs of Cushing's syndrome, a rare condition most often caused by taking high-dose steroid medicines for a long time (NHS).
- - A single cortisol reading tells you very little. Testing has a much clearer role when a doctor suspects Cushing's syndrome or adrenal insufficiency.
- - Morning daylight, a consistent wake time, caffeine kept to the morning, regular daytime movement, slow breathing and earlier alcohol and screens all work with your daily rhythm rather than against it.
- - Supplements are not a shortcut to lowering cortisol, and no supplement in the UK is permitted to claim to.
- - Magnesium, vitamin C and several B vitamins contribute to normal psychological function and to the reduction of tiredness and fatigue, and pantothenic acid contributes to the normal synthesis and metabolism of steroid hormones (GB NHC Register).
If you have spent any time on social media this year, you will have been told that cortisol is puffing up your face, storing fat around your middle, keeping you awake and ruining your skin, and that the fix is a supplement, a morning routine or a particular kind of walk. Some of that has a grain of truth in it. Most of it does not.
The condition in which cortisol genuinely changes how a face and body look is Cushing's syndrome, and the NHS describes it as rare (NHS, Cushing's syndrome). What most people are feeling after a hard month is something far more ordinary, and far more within their control.
So, this piece is for anyone who has heard the word enough to be worried and would like to understand what cortisol actually does, what some of the viral claims get wrong, and what the evidence says about supporting the body during periods of sustained stress. It is a companion to our article on anxiety, and the two inevitably overlap: anxiety and stress are not the same thing, but both can involve the body's stress-response systems, of which cortisol is one part.
What is cortisol?
Cortisol is a steroid hormone made in the adrenal glands, which sit on top of the kidneys. Its release is controlled by a chain of command called the HPA (hypothalamic-pituitary-adrenal) axis: the hypothalamus in the brain signals the pituitary gland, which in turn signals the adrenals. Cortisol's everyday jobs include regulating blood sugar, blood pressure, metabolism, inflammation and the sleep-wake cycle, and helping the body respond to stress; almost every cell in the body has receptors for it (Society for Endocrinology, You and Your Hormones).
The point that gets lost online is that cortisol is not an emergency signal that only appears when something goes wrong. It is a daily hormone that rises and falls on a schedule, and responding to stress is one of its jobs. You could not live without it. Addison's disease, a form of adrenal insufficiency in which the adrenal glands do not make enough cortisol, is rare but serious and needs lifelong treatment (NHS, Addison's disease). Too little cortisol is as much a problem as too much.
Why does the daily cortisol rhythm matter more than the level?
Cortisol follows a strong 24-hour rhythm. Levels begin to rise in the hours before waking and, in most healthy people, increase further during the first 30 to 45 minutes after waking, a rise known as the cortisol awakening response. Cortisol then generally declines across the day, reaching its lowest levels during the night. This rhythm helps prepare the body for activity during the day while allowing cortisol activity to fall during the normal rest period.
Research suggests that the pattern of cortisol across the day can provide useful information that a single measurement cannot. A 2017 systematic review and meta-analysis by Adam and colleagues, covering 80 studies, found that flatter diurnal cortisol slopes, where cortisol falls less markedly from morning to evening, were associated with poorer mental and physical health outcomes (Adam et al., Psychoneuroendocrinology, 2017). The authors noted that flatter slopes may be a marker of, or potentially contribute to, disruption of normal stress and circadian regulation.
Sleep, light exposure, working patterns, psychological stress and other factors can all interact with the body's circadian and stress-response systems. The important point is that cortisol is not simply a number that should be driven as low as possible. In healthy physiology, it follows a pronounced daily rhythm, with higher levels around waking and lower levels at night.
What do 'cortisol face' and 'cortisol belly' get wrong?
There is a real medical condition in which very high cortisol changes the face and body. The NHS describes Cushing's syndrome as a rare condition, most often caused by taking high doses of steroid medicines for a long time and less often by a small non-cancerous growth in the pituitary or adrenal glands, in which excess cortisol can produce a rounded face, extra fat on the neck, upper back and tummy, skin that bruises easily and weak muscles (NHS, Cushing's syndrome). It is diagnosed with specific tests and managed by a hormone specialist (an endocrinologist).
What social media has done is borrow those clinical signs and apply them to everyday life. A puffy face after a short night, a bloated stomach, a stressful week: 'cortisol face', 'cortisol belly'. In reality, ordinary daily stress does not push cortisol anywhere near the levels seen in Cushing's syndrome, and the everyday versions of these things have much more ordinary explanations: sleep, salt, alcohol, the menstrual cycle and what you ate the night before. Longer-term stress can affect sleep and appetite, and that is worth taking seriously. But the idea that you can see your cortisol in the mirror, or fix it with a supplement, is not supported by the evidence.
The practical version: if your face is genuinely changing shape, you are gaining weight quickly around your middle and you bruise easily, see your GP, because those are the signs that warrant a test. If you are tired and puffy after a hard week, you are tired and puffy after a hard week.
Should you test your cortisol?
Cortisol can be measured in blood, saliva or urine, and home saliva kits that sample at several points across the day are now widely sold. A single reading is close to meaningless because the level changes hour by hour. A multi-point saliva profile can show the shape of your daily rhythm, which is the more useful measure, but interpreting it properly takes a practitioner, and results are affected by everything from what time you woke to whether you brushed your teeth first. For most people, the honest answer is that a test tells you what you already know: that a stretch of poor sleep and pressure has flattened your day.
Testing has a much clearer role when a doctor suspects a condition involving abnormal cortisol production, such as Cushing's syndrome or adrenal insufficiency, or when a practitioner is investigating a persistent pattern with you.
What helps? The habits with evidence behind them
Because the rhythm is what matters, the most useful things you can do are the ones that anchor it.
Morning light. Light is the main cue that sets the body clock, and the cortisol rhythm runs on that clock. Getting outside in daylight soon after waking, even on a grey British winter morning, gives it a clear daily signal.
A consistent wake time. Keeping your wake time within about an hour across the week, including weekends, gives the rhythm a steady anchor.
Caffeine, timed. Caffeine raises cortisol. A 2005 study by Lovallo and colleagues found that caffeine increased cortisol across the waking day, and that the response was reduced, but not eliminated, in people who consumed caffeine daily (Lovallo et al., Psychosomatic Medicine, 2005). Coffee is not the enemy, but drinking it late in the day, or using it to push through on no sleep, works against the evening fall. Keeping caffeine to the morning and stopping by early afternoon is the practical version.
Movement, at the right time. Exercise can raise cortisol acutely, particularly when it is prolonged or intense, and this is a normal physiological response. Regular physical activity also has well-established benefits for sleep, mood and health. If hard, late exercise disrupts your sleep, moving it earlier or choosing something gentler may make sense. A brisk daytime walk is an excellent daily option.
Slow exhalations. A Stanford randomised trial found that five minutes a day of breathwork improved mood more than the same time spent on mindfulness meditation over a month, with 'cyclic sighing', a double inhale followed by a long, slow exhale, producing the greatest improvement (Balban et al., Cell Reports Medicine, 2023). It is free, takes five minutes, and can be used at any point in a stressful day.
Alcohol and late screens. Both can disrupt sleep, and sleep is what the rhythm depends on. Neither needs eliminating; both are better moved earlier in the evening.
Talking to someone. If stress has become persistent and is affecting your daily life, your GP is the right first call, and in England you can refer yourself directly to NHS talking therapies without a GP referral (NHS, Talking therapies). Cortisol is downstream of how you are living and what you are carrying, and that is where lasting change starts.
What does a stressed body need from your diet?
First, what supplements cannot do. No supplement lowers cortisol in a way that has been demonstrated to matter for healthy adults, and any product promising to 'balance' or 'reset' it is making a claim it cannot support. Ashwagandha, the herb most often sold for this purpose, has some small trials behind it but no authorised health claim in the UK, and it is not something we would recommend for this purpose on the current evidence.
What diet can do is supply the nutrients the body relies on during demanding periods. A stressed person eating irregularly, drinking more coffee and sleeping less is also the person most likely to fall short of them.
Eat regularly. Cortisol is part of the system that raises blood sugar when it drops. Long gaps between meals and sugar-heavy snacks both push that system harder. Meals built around protein, fibre and slow-release carbohydrate keep things steadier.
Magnesium contributes to normal psychological function, to the normal functioning of the nervous system and to the reduction of tiredness and fatigue (GB NHC Register). A 2020 review in Nutrients by Pickering and colleagues describes how stress can increase the loss of magnesium from the body (Pickering et al., Nutrients, 2020). Our Magnesium Bisglycinate is the form we suggest as a daily foundation, and our guide to the types of magnesium explains how the forms differ.
Vitamin C contributes to normal psychological function and to the normal functioning of the nervous system. Our Vitamin C capsules provide pure ascorbic acid, and Vitamin C Buffered is available if you have a sensitive stomach.
Pantothenic acid (vitamin B5) contributes to the normal synthesis and metabolism of steroid hormones and to the reduction of tiredness and fatigue. It is available on its own as our Vitamin B5 Pantothenic Acid liquid.
Vitamin B6, vitamin B12 and folate each contribute to normal psychological function and to the reduction of tiredness and fatigue. Our B Complex capsules bring these together with pantothenic acid, using methylated forms of B12 and folate, and our guide to B vitamins explains what each one does.
Omega-3 DHA contributes to the maintenance of normal brain function, with the beneficial effect obtained from a daily intake of 250 mg of DHA. Our Omega 3 capsules provide EPA and DHA from the flesh of anchovy, sardine and mackerel.
None of these is a shortcut to lowering cortisol. What they provide are nutrients with important roles in normal psychological function, nervous system function and energy metabolism, which is what matters during demanding periods. A varied diet supplies most of it; where diet is falling short, or a practitioner has identified a gap, a well-formulated supplement can fill it. If you are not sure where you stand, a registered nutritional therapist, such as a BANT member, can look at the whole picture with you, and our team is always happy to talk through the range.
Common questions
What are the symptoms of high cortisol?
Clinically high cortisol, as in Cushing's syndrome, can cause a rounded face, weight gain around the middle and upper back, skin that bruises easily, weak muscles and high blood pressure, and is diagnosed by a doctor (NHS). Everyday stress does not produce these. Feeling wired, sleeping poorly and craving sugar are more likely to reflect a disrupted daily rhythm than a medical condition.
Is 'cortisol face' real?
Cushing's syndrome does change the shape of the face, but it is rare and is most often caused by taking high-dose steroid medicines for a long time (NHS). The puffiness people describe as 'cortisol face' after a stressful week is far more likely to be sleep, salt, alcohol or the menstrual cycle. If your face is genuinely changing shape, see your GP.
How do I lower cortisol naturally?
The aim is a healthy daily rhythm rather than a low level. Morning daylight, a consistent wake time, caffeine before early afternoon, daily movement, slow breathing and earlier alcohol and screens all work with that rhythm. Persistent stress that affects daily life is a reason to speak to your GP.
Do supplements lower cortisol?
No supplement has been shown to lower cortisol in a way that matters for healthy adults, and no supplement in the UK is permitted to claim to. Nutrients including magnesium, vitamin C and several B vitamins do, however, have authorised health claims for their established roles in areas such as normal psychological function, nervous system function and the reduction of tiredness and fatigue. Pantothenic acid also contributes to the normal synthesis and metabolism of steroid hormones.
When should I get my cortisol tested?
Testing is most useful when a doctor suspects a condition involving abnormal cortisol production, such as Cushing's syndrome or adrenal insufficiency. A single home reading says little, because cortisol changes hour by hour across the day.
The bottom line
Cortisol is a daily hormone with a schedule, not an emergency signal, and responding to stress is one of its jobs rather than its whole identity. The shape of that daily rhythm, higher around waking and lower at night, tells you more than any single reading. 'Cortisol face' and 'cortisol belly' borrow the signs of a rare medical condition and apply them to ordinary tiredness: if your body is genuinely changing, see your GP; if you had a hard week, you had a hard week.
The habits with evidence behind them are unglamorous and free: morning daylight, a steady wake time, caffeine kept to the morning, daytime movement, slow exhalations, and earlier alcohol and screens. Supplements are not a shortcut to lowering cortisol. Magnesium, vitamin C, pantothenic acid, the B vitamins and omega-3s provide nutrients with important roles in normal psychological function, nervous system function, energy metabolism and the reduction of tiredness and fatigue, and getting enough of them helps support the body during demanding periods.
Food supplements should not be used as a substitute for a varied, balanced diet and healthy lifestyle. If you are pregnant or breastfeeding, taking medication or have a medical condition, consult your healthcare practitioner before use.
