Adrenocorticotropic hormone fragment 1-24 human (ACTH) is primarily used in medical diagnostics to assess adrenal gland function. It is administered in a test known as the ACTH stimulation test, which evaluates how well the adrenal glands respond to ACTH by producing cortisol. This test is crucial in diagnosing conditions such as Addison's disease, where the adrenal glands are underactive, and Cushing's syndrome, where they are overactive. Additionally, this fragment is sometimes used in research settings to study the mechanisms of hormone regulation and the physiological effects of ACTH on the body. Its synthetic nature ensures consistency and reliability in both diagnostic and experimental applications.