John Buse, M.D., Ph.D.

John Buse, M.D., Ph.D., demystifies the baseline role of cortisol as an essential life hormone and introduces the striking clinical reality that autonomous cortisol hypersecretion silently drives treatment resistance in one-quarter of patients with difficult-to-control type 2 diabetes.

Understanding the Basics  

In the inaugural episode of our insights series, 

Cortisol and Type 2 Diabetes: What Patients Need to Know

, demystifies the biological realities of cortisol. While popular culture frequently labels cortisol strictly as a "stress hormone," Buse explains that it is actually a vital, life-sustaining steroid hormone produced by the adrenal glands. Describing it as the "lube that keeps the machinery going," he notes that baseline levels of cortisol are absolutely essential for critical bodily functions, including sodium excretion. However, when cortisol levels remain chronically elevated, it can cause systematic "mayhem" throughout the body, driving issues like sleeplessness, abdominal fat accumulation and profound metabolic disruptions.

A major highlight of the episode is Buse's discussion of a striking clinical revelation that directly impacts diabetes care. Research indicates that approximately one-quarter of individuals dealing with difficult-to-control type 2 diabetes or resistant high blood pressure actually suffer from a condition called autonomous cortisol hypersecretion. This means the adrenal gland is independently overproducing intermediate levels of cortisol without being prompted by the pituitary gland. For patients, this underlying hormonal surge acts as a silent saboteur, actively worsening their diabetes, driving up blood pressure, increasing central obesity and cardiovascular risk, and even introducing a neuropsychological overlay characterized by heightened anxiety.

Buse draws a clear line between these intermediate hormonal struggles and Cushing syndrome, which represents the classic, extreme manifestation of high cortisol. First described nearly a century ago, Cushing syndrome presents with distinct physical traits, such as a rounded face, skin flushing, a dorsocervical fat pad, purple stretch marks and a severe central pattern of weight distribution. Whether a patient is dealing with classic Cushing syndrome or intermediate autonomous hypersecretion, these abnormal fat distribution patterns carry severe, long-term health complications, significantly increasing the risk of heart attacks, strokes and osteoporotic fractures. This episode serves as an empowering tool for patients who are struggling to manage their metabolic health, providing them with the necessary insights to discuss potential underlying hormonal imbalances with their healthcare providers.

John Buse, M.D., Ph.D.

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