Cortisol: What It Is, and How to Keep Your Levels Balanced

Cortisol is a hormone made by your adrenal glands, which sit on top of your kidneys [1]. It’s often called the “stress hormone,” but it does much more than help you respond to stress. Cortisol supports many essential functions in your body and is released when your brain signals it through a system called the hypothalamic-pituitary-adrenal (HPA) axis [3].

The various roles and functions of cortisol in the body include:

• Regulating Stress Response: Cortisol is central to your body's "fight or flight" response, helping you manage stressful situations by providing quick energy and altering physiological processes [1].
• Controlling Metabolism: It helps regulate how your body uses carbohydrates, fats, and proteins for energy, influencing blood sugar levels by increasing glucose production in the liver [1, 2].
• Reducing Inflammation: Cortisol possesses anti-inflammatory properties, which can help control immune responses and reduce swelling [1].
• Regulating Blood Pressure: It plays a role in maintaining stable blood pressure [1].
• Influencing Sleep-Wake Cycle: Cortisol levels naturally fluctuate throughout the day, being highest in the morning to help you wake up and lowest at night to promote sleep [2, 3].
• Supporting Immune Function: It can influence the activity of your immune system [1].

Cortisol levels naturally vary throughout the day, following a diurnal rhythm. They are typically highest in the early morning and gradually decrease throughout the day, reaching their lowest point around midnight [2].

Time of Day	Typical Cortisol Range (Blood)	Notes
6 a.m. – 8 a.m.	10–20 mcg/dL (276–552 nmol/L)	Cortisol levels are highest in the early morning [2]
Around 4 p.m.	3–10 mcg/dL	Levels decrease throughout the day [2]
Midnight	Lowest levels	Cortisol reaches its lowest point at night [2]

While total cortisol is often measured, sometimes "free" or "active" cortisol levels are assessed. Free cortisol refers to the unbound, biologically active form of the hormone, which can provide a more accurate picture of how much cortisol is actively affecting your cells [7][5][6].

Several factors can affect cortisol levels, influencing what might be considered "normal" for an individual:[7][8]

• Time of day: As mentioned, levels fluctuate significantly throughout a 24-hour cycle [2].
• Stress: Physical or emotional stress can temporarily elevate cortisol [4].
• Exercise levels: Intense exercise can cause a temporary rise [2].
• Medications: Certain drugs, particularly corticosteroids and birth control pills, can influence cortisol levels [2, 4].
• Underlying health conditions: Various medical conditions, including serious illness and some thyroid diseases, can lead to abnormal cortisol production [1, 2].
• Weight and environmental factors: Being overweight or obese, as well as exposure to hot or cold temperatures, may also affect cortisol levels [2].
• Pregnancy: Cortisol levels naturally increase during pregnancy [4].

Cortisol levels can become either too low or too high, leading to various health concerns.

Low Cortisol

When the adrenal glands do not produce enough cortisol, it can lead to a condition known as adrenal insufficiency. The most common cause of primary adrenal insufficiency (Addison's disease) is an autoimmune disorder where the body's immune system mistakenly attacks the adrenal glands [1]. For a deeper dive into symptoms, causes, and potential effects, you can learn more in this guide to low cortisol levels.

Other causes and risk factors for low cortisol include:

• Hypopituitarism: An underactive pituitary gland can lead to secondary adrenal insufficiency because the pituitary gland doesn't produce enough adrenocorticotropic hormone (ACTH), which stimulates cortisol production [1].
• Infections: Certain infections, such as tuberculosis, can damage the adrenal glands [5].[9] [10]
• Sudden withdrawal from corticosteroids: Abruptly stopping long-term corticosteroid medication can suppress natural cortisol production [9].[11] [12]

High Cortisol

Sustained high levels of cortisol can lead to Cushing's syndrome or hypercortisolism. This can arise from internal (endogenous) or external (exogenous) factors [4].

Common causes and risk factors for high cortisol include:

• Corticosteroid Medications: The most common cause of high cortisol is taking high doses of corticosteroid medications (like prednisone) for an extended period, used to treat conditions such as asthma and arthritis [1, 4].
• Chronic Stress: While acute stress causes temporary spikes, prolonged chronic stress can lead to sustained elevated cortisol levels, impacting various bodily systems [4].
• Pituitary Tumors: Benign (non-cancerous) tumors in the pituitary gland can produce too much ACTH, which then overstimulates the adrenal glands to produce excess cortisol. This specific condition is called Cushing's disease [4].
• Adrenal Gland Tumors: Tumors (benign or cancerous) on the adrenal glands themselves can directly produce too much cortisol [1, 4].
• Ectopic ACTH-Producing Tumors: Rarely, tumors in other parts of the body (like the lungs) can produce ACTH, leading to high cortisol levels [10].[13] [14]

If you think your cortisol levels may be out of balance, it’s important to consult a healthcare provider for proper evaluation and guidance. You can also gain insights into your hormone levels from home with the Everlywell 360 Full Body Test, which measures 83 biomarkers—including cortisol—to help you better understand your health.

Imbalances in cortisol can manifest in a wide range of symptoms, affecting both physical and mental health.

Symptoms of Low Cortisol

Symptoms of low cortisol, particularly in conditions such as Addison’s disease, may include:

• Fatigue and weakness: Persistent tiredness and reduced muscle strength [5].
• Weight loss: Unexplained or unintentional weight loss [5].
• Loss of appetite: Reduced desire to eat (anorexia) [1].
• Low blood pressure: Dizziness or lightheadedness, especially when standing (orthostatic hypotension) [5].
• Skin darkening: Hyperpigmentation, especially in scars, skin folds, or gums (more common in primary adrenal insufficiency) [5].
• Gastrointestinal issues: Nausea, vomiting, diarrhea, or abdominal pain [5].
• Salt cravings: Strong desire for salty foods due to electrolyte imbalance [5].
• Low blood sugar: Episodes of hypoglycemia causing shakiness, confusion, or hunger [5].
• Mood changes: Irritability, depression, or anxiety [5].

Symptoms of High Cortisol

Symptoms of elevated cortisol levels (e.g., in conditions like Cushing’s syndrome) may include [4]:

• Weight gain: Often noticeable in the face (“moon face”), neck, and trunk, with relatively slender arms and legs [6, 3].
• Thinning skin and easy bruising: Fragile skin that bruises easily, sometimes with purple stretch marks (striae) [6, 3].
• High blood pressure: Elevated blood pressure [6].
• Muscle weakness: Weakness, particularly in the thighs and shoulders [3].
• Mood changes: Increased irritability, anxiety, depression, or difficulty with emotional regulation [3, 4].
• Sleep disturbances: Insomnia or difficulty falling or staying asleep [4].
• High blood sugar: Increased risk of developing type 2 diabetes [6].
• Menstrual irregularities: Irregular or absent periods in women [3].
• Increased thirst and urination: Often related to elevated blood sugar levels [3].

Managing cortisol imbalances often requires a multi-faceted approach, combining dietary changes, lifestyle adjustments, and, in some cases, medical interventions.

Dietary Changes

While diet alone cannot cure underlying medical conditions causing cortisol imbalances, certain foods and nutrients can support adrenal health and stress management:

• Foods that may help reduce cortisol: Emphasize whole, nutrient-dense foods. Options rich in magnesium and fiber, such as avocados, beans, lentils, and leafy greens, may help lower cortisol. Omega-3 fatty acids (found in fatty fish, nuts, and seeds), vitamin C–rich fruits, and fermented foods may also support stress regulation and overall mood [8].
• Foods that increase cortisol: Limiting highly processed foods, excessive sugar, and refined carbohydrates can help prevent cortisol spikes [4].
• Supplements [15] [16] to balance cortisol: While research is ongoing, some adaptogenic herbs like Ashwagandha and Rhodiola [17] [18] may help the body adapt to stress and potentially modulate cortisol levels [11]. Magnesium and vitamin D are also sometimes recommended. Some evidence suggests that vitamin D supplementation may help reduce cortisol levels in the blood and urine, although more research is needed. Always consult a healthcare professional before taking supplements, especially if you have an existing medical condition or are on medication [4].

Medications and Clinical Treatment

Medical treatment depends on the underlying cause of the cortisol imbalance:

• For Low Cortisol (Addison’s Disease/Adrenal Insufficiency): Treatment involves lifelong corticosteroid replacement, sometimes with mineralocorticoids. Doses may need adjustment during stress, illness, or surgery. In adrenal crisis, immediate hydrocortisone injection is required. Patients should not skip doses and are advised to carry medical identification [5].
• For High Cortisol (Cushing's Syndrome): Treatment options include medications to block cortisol production (e.g., ketoconazole, metyrapone [19] [20] [21] [22]), surgery to remove tumors (pituitary or adrenal), radiation therapy, or, in rare severe cases, removal of the adrenal glands [6].

Lifestyle Changes

Lifestyle changes are crucial for managing stress and supporting healthy cortisol levels:

• Stress Management: Techniques like mindfulness, meditation, deep breathing exercises, and yoga can significantly help reduce stress and its impact on cortisol [4, 6].
• Regular Exercise: Moderate physical activity can help manage stress and promote overall well-being. However, excessive or intense exercise can sometimes temporarily elevate cortisol, so balance is key [2].
• Adequate Sleep: Prioritizing 7–9 hours of quality sleep per night is vital, as sleep deprivation can increase cortisol levels [12,13].[23] [24].
• Maintaining a Healthy Weight: Obesity can contribute to higher cortisol levels [2].
• Limiting Caffeine and Alcohol: Excessive intake of these substances can disrupt cortisol rhythms and increase stress [4].

Testing cortisol levels typically involves lab methods that can assess the hormone in different bodily fluids, providing insights into its production and rhythm.

• Blood Test: This is a common method, usually involving a sample taken in the morning when cortisol levels are highest, and sometimes again in the afternoon or evening to assess the diurnal rhythm [[25] 2].
• Saliva Test: Saliva tests can measure unbound, active cortisol and are often collected at specific times throughout the day, including at night, to provide a detailed cortisol curve [4]. This method is convenient for at-home collection.
• Urine Test: A 24-hour urine collection can measure the total amount of free cortisol excreted over a full day, providing an average of cortisol production [2].

You should consider testing your cortisol levels if you experience persistent symptoms associated with either high or low cortisol, such as unexplained weight changes, chronic fatigue, mood disturbances, or sleep issues [1]. Testing can help identify potential imbalances and guide appropriate medical evaluation and treatment.

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