What Is Endocrinology?

Endocrinology is a branch of medicine that deals with the endocrine system. This is the system that controls the hormones in your body, and the glands that produce them. Many different conditions involve the endocrine system, including diabetes, thyroid disorders, osteoporosis, growth hormone deficiency, infertility, cholesterol problems, high blood pressure, and obesity, among others.

What Endocrinology Involves

Given that endocrinology centers on the endocrine system, let's start by looking at what it is and how it works. The endocrine system is made up of a collection of glands and organs that release hormones and work together to regulate vital functions of our body.

These organs of the endocrine system are:

• Thyroid
• Hypothalamus
• Pineal body
• Pituitary
• Parathyroids
• Adrenals
• Pancreas
• Testes
• Ovaries

At any given time, there are up to 40 hormones at work in the human body. They travel through the bloodstream to target destinations on various organs and tissues in the body.

Hormones are messengers that give instructions to different parts of the body about what to do and when to do it.

There are a variety of bodily processes that involve hormones, including:

• Blood sugar control
• Growth and development
• Tissue function
• Metabolism (the process of getting and maintaining energy in the body)
• Regulation of heart rate and blood pressure
• Sexual development and function
• Reproduction
• Mood

Conditions Treated Within Endocrinology

When it comes to hormones in the body, it's all a matter of balance. And if even one of the many hormones in your body is too high or too low, it can create a hormonal imbalance that affects several bodily functions.

Fortunately, the body is pretty good at regulating its hormones, and in many cases, fixes the imbalances on its own. But it's not always that straightforward.

If your primary care physician notices a hormonal imbalance in your blood work, they'll likely refer you to an endocrinologist, who can help diagnose the problem and come up with a treatment plan.

The most common conditions and diseases within endocrinology fall into one of seven categories:

• Diabetes
• Thyroid disease
• Adrenal disease
• Parathyroid dysfunction
• Pituitary dysfunction
• Reproductive issues

Here are a few examples of specific conditions within each category.

Diabetes

• Type 1 diabetes
• Type 2 diabetes
• Gestational diabetes
• Pre-diabetes

Thyroid Disease

• Hyperthyroidism
• Hypothyroidism
• Hashimoto’s disease
• Nodules
• Thyroid cancer
• Graves’ disease
• Thyroid eye disease

Adrenal Disease

• Addison’s disease
• Adrenal hyperplasia
• Adrenal tumors
• Pheochromocytoma
• Cushing’s syndrome
• Hyperaldosteronism

Parathyroid Dysfunction

• Primary hyperparathyroidism
• Secondary hyperparathyroidism 
• Low blood calcium

Pituitary Dysfunction

• Pituitary tumor
• Pituitary cyst
• Pituitary inflammation

Reproductive Issues

• Polycystic ovary syndrome
• Endometriosis
• Adenomyosis
• Uterine fibroids

Additionally, endocrine conditions can lead to obesity. And being overweight is a risk factor for type 2 diabetes and osteoporosis. 

Treating Endocrine Disorders

Although there is a wide range of treatments used in managing endocrine disorders, the approaches typically fall under three categories:

• Hormone therapy: Prescriptions that restore hormone levels or replace hormones. Personalized insulin treatment for diabetes is an example.
• Medications: Drugs to help stop or slow the body's production of certain hormones. Medications may also be used to provide relief from some of the side effects of endocrine diseases, such as nausea or high blood pressure.
• Surgery: In certain circumstances, surgery is used to treat endocrine disease. Removal of a tumor is an example.

Transgender Medicine and Endocrinology

When a transgender person makes the decision to start gender-affirming hormone therapy, they work with at least one endocrinologist.

• Typically, healthcare providers prescribe a combination of estrogen and androgen-lowering medications for transgender women. This may result in physical changes like enhanced breast growth, reduction of facial and body hair growth, and fat redistribution in a female pattern.
• For transgender men, endocrinologists give testosterone therapy for the purposes of deepening the voice, stopping menstruation, and increasing muscle mass and facial and body hair. 

If you are having gender-affirming hormone therapy, your healthcare providers will discuss the potential side effects of treatment.

Training and Certification in Endocrinology

Healthcare providers who practice endocrinology are known as endocrinologists. All medical endocrinologists must have an MD or DO by completing medical school. Then they must complete a three-year residency in internal medicine, followed by two to three years of fellowship training in endocrinology, diabetes, and metabolism.

It is also possible for an endocrinologist to focus on a subspecialty, like pediatric endocrinology or reproductive endocrinology and infertility.

Some endocrinologists also have a Ph.D. or another advanced degree in one of the hard sciences. In order to diagnose patients, endocrinologists frequently use laboratory testing, and many who chose this specialization have a background in biochemistry and research.

History of Endocrinology

Though it's unclear exactly when elements of endocrinology were first understood, one of the first recognized references to the discipline can be found in Hippocrates' theory of the four humors (black bile, phlegm, yellow bile, and blood), which dates back to around 400 B.C.E.

Shortly after, Aristotle recorded specific endocrinological observations, including changes in behavior and appearance in castrated roosters. By the Middle Ages, it was thought that human organs came with special powers, so in some instances, the winners of a battle ate their enemies' hearts, brains, or gonads to gain strength in related areas.

The development of endocrinology as we know it today — much like most of modern medicine — has taken place over the last two centuries, through vast amounts of research.

A Word From Verywell

Hormones promote normal puberty and metabolism. Their function can also be impacted by endocrine conditions.

In most cases, you won't need to see an endocrinologist unless your primary care doctor recommends it. If you need an endocrinology consultation, you will see an endocrinologist who has advanced training in managing the glands and organs that produce and regulate all the hormones we need for everyday function.