Definition and Overview

Endocrinology is a branch of medicine that deals with the endocrine system, the organs that are associated with it, the diseases and conditions that may arise from any of the associated glands and organs, and the overall metabolic function of the body. It can also include any behavior or mental activity that can be associated with or develop because of changes in the endocrine system.

The endocrine system is composed of many different glands such as the pancreas, adrenal glands above the kidneys, pituitary gland, thyroid glands, and some parts of the reproductive such as the ovaries and the testes.

These parts are responsible for the production and secretion of hormones, which act as chemical messengers that tell cells or tissues to function in a certain manner or to carry out activities that are essential to life. For instance, the pancreas creates insulin, which helps store and deliver blood sugar (glucose) to cells to give them energy. Since the glands do not have ducts, these hormones are delivered through the bloodstream.

The system may also include specific organs that can function similarly as these glands. Some good examples are the kidneys, which work with the liver and skin to harness vitamin D to control the levels of calcium in the blood. The body naturally produces Vitamin D although its development is sparked by exposure to sunlight.

Changes to any of the glands due to a disease or congenital defect, as well as other factors that can cause hormonal imbalance, are a major concern for endocrinologists, the specialists who are trained in this area.

All endocrinologists are trained to deal with any condition affecting the endocrine system, although they may also specialize in reproduction, pediatrics, internal medicine (which covers anything that is not part of reproduction and pediatrics), behavioral, oncology, and comparative analysis.

When You Should See an Endocrinologist

A person may consider seeing an endocrinologist if:

  • Factors that can affect hormone production are present. Three of the most important factors are stress, lifestyle, and age.
  • A person carries certain genes that increase the risk of hormone-related problems. Genetics can affect the production of hormones in many different ways. A woman who carries defective genes called BRCA1 and BRCA2 has more than 70% increased risk of developing varian and breast cancer. Both type 1 and type 2 diabetes are strongly connected to genes.
  • Certain signs of hormonal imbalance are detected. The signs and symptoms can be very subtle or broad and they can be associated with other diseases not related to the endocrine system. These may include hair loss and exhaustion or fatigue. Some, on the other hand, are distinct such as infertility, difficulty in controlling body temperature, and obesity.
  • The person has a congenital defect that may affect the functions of the endocrine system.
  • The person who suffers from other conditions that may prevent the proper production of hormones like cancer in the glands.
  • There are mental or behavioral changes observed. Depression, for instance, is associated with certain hormones. Hormonal imbalances may increase a person's level of stress, deprive him or her of sleep, or modify the appetite, all of which are considered depressive symptoms.
  • A person has been diagnosed with an endocrine-related condition and is under medication or other forms of treatment.

An endocrinologist spends at least 20 years in training, specializing, and enhancing his or her expertise. At least four years are spent in medical school followed by between three to four years of residency training. They then proceed to a fellowship, which may be two to three years. Endocrinologists should be board certified.


  • American Association of Clinical Endocrinologists
  • The New England Journal of Medicine
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