What Hormones Are: A List of Human Hormones and Their Functions

Hormones are considered chemical messengers within the human body. See the list of hormones and their functions.

What are Hormones?

Within the human body are chemical messengers called hormones. These hormones are created in the endocrine glands, and they control most major bodily functions. Hormones may regulate basic functions such as hunger and satiety, as well as more complex functions like mood or reproduction. Understanding the major hormones in the body will help you take charge of your body for better health and wellness.

A List of Major Human Hormones

Following is a list of major human hormones with basic descriptions of responsibilities for each.

Pituitary Gland & Hypothalamus

Your pituitary gland is about the size of a pea and sits in a bony hollow just behind your nose bridge, and it is attached to the base of your brain by a thin stalk. Your hypothalamus is situated right above the pituitary gland.

The pituitary gland is considered the “master gland” as it helps regulate the functions of all the other endocrine glands such as the thyroid and adrenal glands. However, the pituitary doesn’t work alone. It has help from the hypothalamus. Together, they regulate the activity of most of your other endocrine glands. The hypothalamus signals the pituitary gland to stimulate hormone production. Essentially, your hypothalamus is like an on and off switch that conducts the pituitary gland to act.

The pituitary gland’s main function is to secrete hormones into your bloodstream, and the hypothalamus plays a crucial role that includes the release of hormones and the regulation body temperature, appetite, thirst, libido, sleep, and mood.

Thyroid Gland

Your thyroid gland is situated in your neck, in front of the larynx and trachea at the fifth through seventh cervical and first thoracic vertebrae. It is surrounded by a fibrous capsule and resembles a butterfly in shape and is a highly vascular gland that weighs about 25 grams.

The thyroid gland secretes two hormones known as thyroxine (T4) and triiodothyronine (T3) to help the body produce and regulate the hormones adrenaline and dopamine that activate emotional responses such as pleasure, excitement, and fear. The thyroid gland also helps regulate metabolism which converts food or fuel into energy to run cellular processes within the body.

*** NOTE: You may want to read more about the thyroid.

Parathyroid Glands

You have four parathyroid glands which are embedded in the posterior surface of each lobe of the thyroid gland. Each weights approximately 50 grams each. They are surrounded by fine connective tissue capsules.

The parathyroid glands secrete parathyroid hormones which regulate your blood calcium levels. This is achieved by increasing the calcium absorption from your small intestine and reabsorption from your renal tubules.

Adrenal Glands

You have two adrenal glands, each situated on the upper pole of each kidney and enclosed with the renal fascia. Each is about four centimeters long and three centimeters thick. The adrenal glands are composed of two parts which have different structures and functions. The outer part is called the adrenal cortex, and the inner part is called the adrenal medulla.

The adrenal cortex is responsible for creating hormones that conserve sodium in the body, increase blood glucose levels, and regulate sex hormones such as estrogen. The adrenal medulla helps control stress.

Pancreatic Islets

Your pancreatic islets are the endocrine portion of your pancreas. They take the form of several small clusters of cells called islets of Langerhans or just plain islets. Roughly, humans have about one million islets which are seemingly pale-staining groups of cells embedded in a sea of darker-staining exocrine tissue.

The pancreatic islets produce hormones called glucagon, insulin, and somatostatin. Glucagon increases blood glucose levels while insulin reduces blood glucose levels. Somatostatin inhibits the secretion of both glucagon and insulin, as well as the secretion of growth hormone from the pituitary.

Pineal Gland (Thalamus)

Your pineal gland is about 10 millimeters long and is reddish brown in color. Surrounded by a capsule, it is a small body attached to the roof of the third ventricle and is connected by a short stalk of nerves of which many end in the hypothalamus.

The main hormone secreted by the pineal gland is melatonin. Secretion is controlled by daylight or darkness and fluctuate during each 24 hour period, the highest being at night. It is also influenced by the number of daylight. Melatonin helps control sleep and wake cycles. It also inhibits the growth and development of sex organs before puberty.


When your hormones are in proper balance, they help your body to thrive. Therefore, it’s important that you take care of your body by eating a proper diet filled with whole foods and low in sugar. Exercise, sleep, and stress management are also part of a healthy lifestyle.