What is Endocrinology?


Written by Elite HRT on March 17, 2021

Medically reviewed by

Camille Freking, Regulatory Affairs Specialist, MEDICAL ADVISOR

You may have heard the word endocrinology in passing when talking to a friend or family member, or when you are visiting the doctor. 

Endocrinology is the study of the endocrine system. Endocrinology is a very complex study and requires thorough understanding of many large processes in the body. 

To fully understand endocrinology it is important to know the basics of what endocrinology is, who practices endocrinology, what it takes to be an endocrinologist, how the endocrine system works, and of course what can happen when it is not working. 

Keep reading to learn all of this information about endocrinology and more!

Endocrinology 101

You already know that endocrinology is the study of the endocrine system, but what does that entail? 

The endocrine system includes all of the glands in your body that release hormones. These hormones control many of the bodily functions from when you sleep, how you break down foods, how you grow, and even how much you have to go to the bathroom. 

Because all of these hormones work in synchrony they all have to be in the right levels in your body to keep things running smoothly. If they are not working well or your body is making too many or too few hormones, you could end up having a condition that needs to be addressed by an endocrinologist. 

What is an Endocrinologist?

An endocrinologist is a medical doctor that specializes in conditions related to hormones and other biochemical processes. There are multiple types of endocrinologists including a pediatric endocrinologist that focuses on children with endocrine disorders, reproductive endocrinologists that focus on female hormones and infertility, and an internal medicine endocrinologist that can see all patients with endocrine disorders. 

Endocrinologists can work in a hospital to assist with patients that are having worsening conditions that need immediate attention. They can also work in an outpatient practice where they get referrals from primary care providers to address more complex conditions. No matter where they work they are able to help patients diagnose, treat, and manage their hormone related conditions. 

Endocrinologist Training 

To become an endocrinologist takes years of schooling, practice, and training before they are able to work as a doctor alone. 

The training all begins with a 4 year bachelor degree of their choice. Afterwards, they will go on to complete 4 years of vigorous schooling in medicine. They will then choose a specialty of internal medicine, pediatrics, or obstetrics and gynecology and complete a 3-7 year residency in that area. Afterwards, they will do a 2 or 3 year fellowship in endocrinology where they work with an endocrinologist to learn the details of the specialty. 

This training is a 13 to 18 year process where they learn to be the best endocrinologist. 

The Endocrine System

The endocrine system is very intricate and requires extensive knowledge of each gland and hormone. While it is impossible to explain every part of the endocrine system, we can discuss some of the most important glands and hormones that are in the body. 

> Pituitary Gland

The pituitary gland is one of the most important glands in the body and is even called the master gland. The pituitary gland releases 8 different hormones which all act on various parts of the body. To name a few, it releases growth hormone, luteinizing hormone, and thyroid stimulating hormone. With just these 3 hormones out of the 8, it is impacting the musculoskeletal, nervous, reproductive, and digestive systems. Some of the most common diseases of the pituitary gland are acromegaly or gigantism, diabetes insipidus, and hypogonadism or testosterone deficiency. Because the pituitary gland signals to many other glands to release more hormones it has an impact on the functioning of those glands as well. 

> Testicles

The testicles are an important organ and gland in those assigned male at birth. The testicles are responsible for producing testosterone and creating sperm. Testosterone is a vital hormone in men and has a big impact on libido, bone density, muscle growth, strength, producing sperm, and their mood. The testicles are only able to produce testosterone after they get a signal from luteinizing hormone from the pituitary, so they must work together to keep everything working well. 

> Thyroid Gland

The thyroid gland is another important gland that has many functions. It is located in the neck near the Adam’s apple. The thyroid gland plays a role in metabolism, the nervous system, muscular system, cardiovascular system, and digestive system. The thyroid releases the hormones triiodothyronine (T3) and thyroxine (T4). The conditions of this gland are hypothyroidism and hyperthyroidism. They can change your weight, body temperature, muscle contraction, heart rate, and bowel movement regularity. Hashimotos is a common form of hypothyroidism that can be diagnosed by a healthcare provider. 

> Pancreas

The pancreas is a large fatty gland located across the top of your abdomen. It releases the hormones gastrin, somatostatin, glucagon, and the most well known hormone insulin. The pancreas largely controls digestion of food and the control of blood sugar levels. If these are not well controlled it could result in diabetes mellitus. Diseases of the pancreas can be related to genetics, lifestyle choices, obesity, and other contributing factors. If the pancreatic hormones are not managed or addressed they could have life threatening consequences as well as complications to other parts of the body. 

> Adrenal Glands

The adrenal glands are 2 small glands that sit on top of each kidney. They make hormones that control metabolism, blood pressure, stress response, the immune system, and more. Some of their largest producers are cortisol, epinephrine, and norepinephrine which are all used in the stress response. The release of these hormones in times of flight or fight change the body to be better fit for survival. Some of these changes include an increase in heart rate, slowed digestion, and decreased urination. If there are too many or too few of the adrenal hormones it could result in diseases such Addison’s disease, hyperaldosteronism, cushing’s disease, or adrenal insufficiency. All of these conditions need to be carefully monitored and managed with the help of an endocrinologist. 

When the Endocrine System Malfunctions

One way the endocrine system can malfunction is if the gland is producing too much or too little hormone. Whether there is too much or too little will determine exactly which endocrine disorder will occur. For example, if the pancreas is not making enough insulin the person would develop diabetes mellitus type 1. Another instance of this is if a child is not getting enough growth hormone, they will not have adequate growth resulting in a small stature and other potential health complications. 

Luckily, the body has many systems in place to keep the balance of hormones in check. There are negative feedback loops between multiple glands and body structures to adjust the levels of hormones being produced. 

To simplify this negative feedback loop consider the supply and demand in a restaurant. If the pizza restaurant chef is making more pizzas than they need, the cashier will tell the chef to slow down or stop making so many pizzas so that they do not have an excess. The same thing happens in the body. 

For example, if the thyroid gland is producing too much T4, the pituitary gland will be signaled to stop making so much TSH to balance out the levels. If this negative feedback loop is altered in any way it could result in imbalanced hormones and ultimately a hormone disorder. 

One other way that hormones can change is during aging. As the body ages it produces few hormones than it did at a younger age. While this is a natural process, it can result in unwanted side effects. One hormone that does this is testosterone. 

As men get older their testosterone can reduce as much as 1.6 percent each year. This can result in changes in mood, strength, sexual functioning, and more. Even though this is an expected finding as men age, there are still options through an endocrinologist such as hormone replacement therapy that can help to reduce these unwanted symptoms. 


It is easy to see that the entire endocrine system is not understood in a single learning session. It takes years to fully understand its inner workings. But, the basics of endocrinology are that it is the study of the endocrine system, which includes the hormones and glands in the body. The body usually keeps these hormones in balance via negative feedback loops. But when a step in the process is malfunctioning either from a structural or chemical imbalance, it can have very negative impacts on the body. Even though we already have a wealth of knowledge on the endocrine system, there is always more to learn!


Testosterone for the aging male; current evidence and recommended practice – National Institutes of Health 

Pituitary Gland: What Is It & Definition – Cleveland Clinic

Understanding How Testosterone Affects Men – National Institutes of Health 

Thyroid Hormone Production and Function – University of Michigan