Addison’s disease, also known as primary adrenal insufficiency or hypoadrenalism, is a rare disorder of the adrenal glands. The adrenal glands are two small glands that sit on top of the kidneys. They produce two essential hormones: cortisol and aldosterone. In Addison’s disease, the adrenal gland is damaged, and not enough cortisol and aldosterone are produced. It can affect people of any age, although it’s most common between the ages of 30 and 50. It’s also more common in women than men. Most people with the condition live a normal lifespan and are able to live an active life, with few limitations. However, many people with Addison’s disease also find they must learn to manage bouts of fatigue and there may be associated health conditions, such as diabetes or an underactive thyroid.