An endocrinologist is a physician with extensive training in understanding, diagnosing and treating conditions related to the endocrine system. The endocrine system regulates the balance of hormones. Conditions of the endocrine system involve an over-abundance, or deficiency of a certain hormone. While there is a range when it comes to the amount of a hormone that is deemed normal in a human, these specialists determine whether a person's amount of hormone is indicative of a health concern.

An internist is a physician who focuses on the diagnosis and treatment of conditions that affect the adult population—both acute and chronic.These doctors are often who adults see as their primary physicians because they treat a broad range of illnesses that do not require surgical or specialist interventions. They also work to help a patient maintain optimal health in order to prevent the onset of disease.In addition to treating the common cold and flu, internists also treat chronic diseases like diabetes and heart disease.