Cortisol becomes a wellness trend

Cortisol, known as the stress hormone, is now a popular topic in wellness culture, with a wide range of products such as gummies, drinks, and even saliva tests aimed at managing its levels. Endocrinologist Marie-Pierre Moisan, author of But is it really the cortisol?, questions the commercial success of these products.

Cortisol's biological role

Cortisol is a vital hormone produced by the adrenal glands, responsible for regulating blood sugar, controlling inflammation, and influencing blood pressure and alertness. It also plays a role in the wake-sleep cycle, peaking when a person wakes up and decreasing in the evening as melatonin takes over.

Stress and cortisol are not always linked

Stress does not always raise cortisol levels. In the face of immediate danger, the body reacts quickly with adrenaline, while cortisol mobilizes energy more slowly. Prolonged stress does not necessarily lead to continuous cortisol elevation. For example, people with post-traumatic stress syndrome often have lower cortisol levels than average.

Cortisol and health claims

Weight gain, fatigue, and acne are often linked to cortisol, but the evidence is not conclusive. While cortisol can promote abdominal fat storage and increase the urge to snack, the concept of a "cortisol belly" is a myth. Chronic fatigue is more likely due to lack of sleep, which affects cortisol levels rather than the other way around.

Cortisol testing and home kits

Screening tests for cortisol are not typically recommended for symptoms like fatigue, weight gain, or sleep disorders, which are common to many diseases. According to Moisan, cortisol tests are only prescribed if there is a suspicion of Cushing's syndrome or adrenal insufficiency. Home saliva and capillary tests are unreliable due to fluctuating cortisol levels based on time of day, stress, and other factors.

Supplements and diet for cortisol

Products and methods claiming to "regulate" cortisol include ashwagandha, Griffonia, and rhodiola. While some studies support ashwagandha, the evidence for other plants is limited and often comes from sites that sell the products. Dietary programs that claim to regulate cortisol may have a real mechanism, as irregular eating patterns can raise cortisol levels. However, many other claims, such as the benefits of magnesium and polyphenols, are common nutrition advice repackaged for marketing.