Cortisol Is Good for You

Ball-and-stick model of the cortisol molecule

Source: Ben Mills/Image generated in Accelrys DS Visualizer.

Cortisol is a hormone that is released by the adrenal glands, which sit on top of your kidneys. The term “hormone” is reserved for any chemical messenger that travels through the bloodstream and has an effect on some tissue in the body. The primary job of cortisol is to get fuel—in this case, glucose—to working cells. Despite being known primarily as a stress hormone, cortisol is released throughout the day. It is highest in the morning as we start the day and lowest overnight while we rest.

The normal range of cortisol for a healthy adult is between 30 and 145 nanomoles per liter over 24 hours (Petersenn et al., 2014). This range is bracketed by the highest levels in Cushing’s disease, which is typically caused by a tumor in the pituitary gland and leads to increased cortisol release. The lowest levels are found in people with Addison’s disease, which is typically caused by damage to the adrenal gland.

Addison’s disease provides a good example of the importance of cortisol. In the 1850s, Thomas Addison described patients suffering from fatigue and muscle degeneration, among other symptoms. Addison showed that these patients could be successfully treated with “adrenal extracts,” which included cortisol. Prior to this discovery, most of Addison’s patients died within two years of diagnosis. Today, these patients are able to lead normal lives by taking doses of cortisol (Munck et al., 1984).

What does cortisol do?

Most of us are familiar with the use of synthetic versions of cortisol, such as hydrocortisone, used to reduce inflammation. Hike into some poison ivy? Rub some hydrocortisone on there and the redness and swelling will go away in a few days. These anti-inflammatory effects are another of cortisol’s jobs. Cortisol is released in response to acute inflammation and helps to reduce it quickly, but it also prepares the body to fight future inflammation.

So why would we want to reduce our cortisol? Cortisol is a good example of the saying, “Moderation in all things.” A quick cortisol response is helpful in fighting off an infection, but a prolonged elevation of cortisol can lead to a host of negative outcomes. Cortisol, like many chemicals, acts in very different ways depending on the dose and timing. Briefly inhibiting inflammation by redirecting metabolic resources from the immune system is good. Long-term inhibition of the immune system makes us more likely to get sick.

Back to its role as a stress hormone, cortisol is necessary for getting fuel to working muscles in response to a stressful event. This allows us to quickly cope with the stress and survive. The problem comes after we’ve overcome the stressful event, and the body continues to pump out cortisol. Or when the stressful event doesn’t end, and all the fuel that our muscles need during stress starts to have negative consequences, such as muscle wasting and a suppressed immune response.

So, is cortisol good or bad for you? The answer is “yes.” In the same way that glucose (sugar) in small doses is necessary for survival but can lead to trouble at higher levels. Yes, cortisol can be damaging at high levels, but it is also essential for survival and good health. Keep this in mind when you’re trying to balance out your cortisol levels.