Cortisol: Symptoms, Causes & How to Lower It

Written by Dr. Simon Khela MBChB MRCGP, GMC Registered Doctor

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Few hormones have had quite the social media makeover that cortisol has. “Cortisol face,” “cortisol belly,” and countless supplements promising to “balance your cortisol” have turned a genuinely important hormone into something closer to a wellness villain. As a GP, I find myself spending as much time correcting misconceptions about cortisol as I do explaining what it actually does, and the two conversations are usually more interesting than patients expect.

This guide explains what cortisol actually is, what happens when levels are genuinely too high or too low, what causes this, and which approaches to lowering cortisol are backed by real evidence, as opposed to the ones sold to you in a bottle.

What Is Cortisol? A Quick Answer

Cortisol is a hormone made by your adrenal glands, two small glands that sit above your kidneys. It's often called the “stress hormone,” but according to the Society for Endocrinology, cortisol also plays an essential role in regulating blood sugar, blood pressure, metabolism, inflammation and your sleep-wake cycle. Levels naturally rise in the morning and fall overnight. Genuinely high or low cortisol are recognised medical conditions, Cushing's syndrome and Addison's disease respectively, but everyday stress causes only mild, temporary changes, not a disorder. Lifestyle changes such as better sleep, regular moderate exercise and stress management have real evidence behind them for keeping cortisol in a healthy range.

What Does Cortisol Do?

Cortisol affects nearly every system in your body. Its roles include:

• Regulating how your body uses glucose (blood sugar) for energy
• Helping control blood pressure
• Reducing inflammation
• Influencing metabolism of fats, proteins and carbohydrates
• Supporting your sleep-wake cycle, with levels naturally highest in the morning and lowest at night
• Playing a role in memory and how your brain responds to stress

Cortisol and the Stress Response

When you encounter a stressful situation, your brain signals your adrenal glands to release cortisol, alongside adrenaline, as part of the “fight or flight” response. This is a normal, healthy, and genuinely useful reaction, it's what helps you react quickly to a real threat. The system is called the hypothalamic-pituitary-adrenal (HPA) axis, and it's designed to switch on quickly and then switch off again once the stressful situation has passed.

Many patients are surprised to learn that the problem isn't cortisol being released during stress, that's exactly what it's meant to do. The concern is when this system stays switched on for far longer than it should, through chronic, ongoing stress rather than a short-lived challenge.

Symptoms of High Cortisol

When cortisol is genuinely elevated for a prolonged period, it can cause:

• Weight gain, particularly around the face, upper back and abdomen, often with slimmer arms and legs
• A round, red or puffy face, sometimes called a “moon face”
• Skin that bruises easily, with purple or pink stretch marks
• Muscle weakness, particularly in the shoulders and hips
• High blood pressure and high blood sugar
• Mood changes, including anxiety, irritability or low mood
• Poor sleep

Cushing's Syndrome: When High Cortisol Becomes a Medical Condition

When these symptoms occur together and persist, this is known as Cushing's syndrome, described in detail by the NHS. The most common cause by far is long-term steroid medication used for other conditions, such as asthma or rheumatoid arthritis, rather than stress alone. Less commonly, it's caused by a tumour on the pituitary or adrenal gland. The Pituitary Foundation has detailed patient information if a pituitary cause is suspected or confirmed.

Symptoms of Low Cortisol

Genuinely low cortisol causes a different pattern of symptoms:

• Persistent fatigue
• Unintentional weight loss
• Loss of appetite
• Low blood pressure, sometimes causing dizziness on standing
• Low mood
• Darkening of the skin, particularly in skin creases or scars, in some cases

Addison's Disease: When Low Cortisol Becomes a Medical Condition

Persistently low cortisol is known as adrenal insufficiency, or Addison's disease when the adrenal glands themselves are damaged. According to NHS inform, it affects around 8,400 people in the UK and is most commonly diagnosed between the ages of 30 and 50. Early symptoms are easily mistaken for depression or a viral illness, which is part of why diagnosis can take time. Rarely, a sudden, severe drop in cortisol causes an adrenal (Addisonian) crisis, a medical emergency involving severe weakness, vomiting and collapse, which needs immediate hospital treatment.

What Causes High or Low Cortisol?

Common contributors to raised cortisol include:

• Chronic, ongoing stress, which keeps the HPA axis switched on for longer than it's designed for
• Long-term use of steroid medication
• Obesity, which is linked to altered cortisol regulation
• Poor or disrupted sleep, including from conditions such as sleep apnoea, which interferes with the normal overnight dip in cortisol
• Tumours affecting the pituitary or adrenal glands, in less common cases

Low cortisol is usually caused by:

• Autoimmune damage to the adrenal glands, the most common cause of Addison's disease in the UK
• Problems with the pituitary gland, which controls the signal to release cortisol
• Suddenly stopping long-term steroid medication rather than reducing the dose gradually

Effects of Long-Term High Cortisol on the Body

Persistently high cortisol doesn't just cause symptoms in isolation, it has knock-on effects worth understanding:

• Cardiovascular strain: cortisol has a direct effect on blood pressure, and persistently high levels are linked to sustained hypertension
• Metabolic changes: high cortisol is associated with raised cholesterol and triglycerides, alongside higher blood sugar
• Bone health: prolonged high cortisol is a recognised cause of weakened bones and osteoporosis, since it interferes with normal bone formation
• Immune effects: cortisol suppresses inflammation, so very high levels over time can make you more prone to infections

One of the most common concerns I see in practice is a patient who's read that stress is “damaging their cortisol” and wants a quick fix. The honest answer is that these effects come from sustained, significant elevation, the kind seen in Cushing's syndrome, not from the everyday stress most people are describing.

How Is Cortisol Tested?

Cortisol can be measured through:

• A blood test, usually taken in the morning when levels are naturally highest
• A 24-hour urine collection
• A saliva test, sometimes taken late at night to check for an abnormal pattern

Timing matters because cortisol naturally rises and falls throughout the day, so a single result needs to be interpreted in context rather than compared to a single “normal” number. Understanding how long blood test results generally take can help set expectations, since cortisol testing sometimes needs repeating at different times of day, or alongside other hormone tests, before a clear picture emerges.

A question I am frequently asked is whether over-the-counter cortisol test kits, sold directly to consumers, are worth using. A single home test rarely gives a useful answer on its own, since interpretation depends on timing, technique and the wider clinical picture. If there's a genuine concern about your cortisol levels, a referral to a specialist, an endocrinologist, allows proper, structured testing rather than a single snapshot result.

How to Lower Cortisol

For most people asking how to reduce cortisol levels, the goal isn't treating a medical condition, it's supporting a body that's been under sustained stress. The evidence here is genuinely reassuring, because the things that help are largely the same sensible habits that support health more broadly:

• Prioritising consistent, adequate sleep, since poor sleep is one of the more reliable ways to keep cortisol elevated
• Regular, moderate exercise, though it's worth knowing that very intense or excessive exercise can temporarily raise cortisol further, so balance matters more than intensity
• Reducing caffeine and alcohol, both of which can affect cortisol patterns
• Building in genuine rest and recovery time, not just physical rest but mental downtime
• Maintaining social connection, which has a measurable calming effect on the stress response

Structured approaches to stress genuinely help too. Practical stress management techniques, including mindfulness-based approaches, have research evidence behind them for lowering cortisol, not just making you feel calmer. Where weight is a contributing factor, a structured weight management programme can help, given the two-way relationship between weight and cortisol regulation. For ongoing stress or anxiety that feels difficult to manage alone, a confidential mental health assessment is a legitimate and often underused option, not a last resort.

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These are the two genuine medical extremes; most people with everyday stress sit well within a normal range and won't develop either condition.

Cortisol and Weight: Separating Fact from Wellness Marketing

This is probably the single most searched-for angle on cortisol, and it deserves a genuinely balanced answer rather than either dismissal or exaggeration.

• The genuine science: cortisol does influence where fat is stored, and in Cushing's syndrome, characteristic central weight gain is a real, well-documented feature
• The oversimplification: for most people carrying extra weight, cortisol is one of many contributing factors, alongside diet, activity levels, sleep, genetics and other hormones, rarely the dominant cause on its own
• The unsupported leap: the idea that a specific supplement, tea, or “cortisol detox” can meaningfully target abdominal fat by “lowering cortisol” isn't backed by good evidence

One of the most common concerns I see in practice is a patient who's spent money on cortisol-targeted products before addressing the fundamentals- sleep, activity, and overall diet quality- that have a far larger, better-evidenced effect on weight and genuinely do influence cortisol as a side effect of improving general health, rather than the other way around.

Common Myths About Cortisol

• Myth: “Adrenal fatigue” is a recognised medical condition. Fact: This isn't a diagnosis recognised by endocrine specialists. Genuine adrenal underactivity is called adrenal insufficiency, or Addison's disease, and is diagnosed through proper testing, not a symptom checklist.
• Myth: “Cortisol face” or “cortisol belly” are medical diagnoses. Fact: These are social media terms, not clinical ones. Facial and abdominal changes can have many causes, and genuine cortisol-driven changes are part of the broader picture seen in Cushing's syndrome, not an isolated finding.
• Myth: Cortisol detox drinks and supplements lower cortisol. Fact: There's no good evidence that any supplement or “detox” product meaningfully lowers cortisol; the interventions with real evidence are sleep, exercise balance, and stress management.
• Myth: If you feel stressed, your cortisol must be high. Fact: Feeling stressed doesn't reliably predict your actual cortisol level, and you can't tell from symptoms alone without proper testing.
• Myth: High cortisol from stress is basically the same as Cushing's syndrome. Fact: The scale is completely different; everyday stress causes mild, temporary changes, while Cushing's syndrome involves sustained, significantly elevated levels causing genuine physical changes.

When to See a GP

It's worth seeing a GP if you notice:

• Unexplained weight gain or weight loss
• New bruising, stretch marks, or thinning skin without an obvious cause
• Persistent fatigue alongside dizziness, low blood pressure, or loss of appetite
• Symptoms that started or worsened after beginning, or stopping, steroid medication

A private GP appointment is a sensible way to discuss these symptoms properly and decide whether testing or specialist referral makes sense, rather than trying to interpret symptoms against wellness content online.

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Frequently Asked Questions about Cortisol Symptoms