Adrenal insufficiency is a disorder that can be life-threatening and its most common symptoms are fatigue, weight loss, joint pains and aches, dizziness, and low blood pressure. This disorder is characterized by the failure of the adrenal glands to produce appropriate amounts of cortisol, either due to a defective and damaged adrenal gland, or a pituitary problem causing a deficiency of ACTH (the pituitary hormone that regulates the functioning of the adrenals). Patients affected by a thyroid disease such as Hashimotos’s thyroiditis or Graves’ disease are at a higher risk for having adrenal insufficiency. Adrenal insufficiency causes low production of cortisol, which is a hormone released by the adrenals that helps the body fight infection and respond appropriately to stress. Because adrenal insufficiency can be life-threatening, it is important to get a diagnosis quickly so you can begin treatments. The most precise way to determine if adrenal insufficiency is present is through a challenge test to the adrenals called an ACTH stimulation test. An ACTH stimulation test is a test that challenges the adrenal glands with an IV injection of ACTH and testing the cortisol levels over an hour period. Research has shown that this test is very helpful when ruling adrenal insufficiency in as a diagnosis, but is less accurate when trying to rule out this disorder as a diagnosis. When a diagnosis of adrenal insufficiency has been proven, you will be treated with hydrocortisone in physiological doses to replace the deficit of cortisol. For thyroid patients it is important to consider adrenal insufficiency if you suffer from persistent fatigue, and have your doctor perform the right testing. Treating adrenal insufficiency won’t only improve your quality of life, but it could save your life.