Hormones and Your Health: An Essential Guide

Hormones affect more than just mood. The vital chemicals enable daily bodily functions, reproduction, movement, and more.

Medically Reviewed

Hormones affect more than just mood. The vital chemicals enable daily bodily functions, reproduction, movement, and more.

We tend to think of certain times in life, such as puberty, pregnancy, and the transition to menopause as hormone-fueled, but the truth is that our hormones influence the health of our bodies and minds every single day.

What Are Hormones? A Description of the Messenger Chemicals

So what exactly are hormones? Hormones are special chemicals that travel through the bloodstream. “Think of them as the body’s internal WiFi,” says Randi Hutter Epstein, MD, (1) the author of Aroused: The History of Hormones and How They Control Just About Everything. They carry messages from the glands where they are produced to cells in different parts of the body. These chemical messages help to “turn on” or “turn off” cellular processes that control appetite, growth, stress, blood sugar, sleep cycles, sex drive, and sexual function, to name a few. (2)

Hormones Play an Important Role in Daily Healthy Living

“The term ‘hormonal’ has become synonymous with ‘moody,’" says Dr. Epstein. While hormones do affect mood, they do much more in the body than that, she says. (1)

Eat, Breathe, Love: Hormones Help You Do It All

Hormones are involved in some way in most bodily functions — from the basic (hunger, heart rate) to the complex (reproduction and emotion). (2)

Neurotransmitters: Hormones That Help the Brain Communicate With the Rest of the Body

Some hormones, such as serotonin and dopamine, also function as neurotransmitters — chemicals that relay messages between nerve cells in the brain and from neurons to muscles. Neurotransmitters help to coordinate movement and control mood and cognition. (3)

Hormones Are Produced by Glands That Make Up the Endocrine System

Glands are organs that secrete substances. Major hormone-secreting glands in the body include: pituitary gland, hypothalamus, thymus, adrenal glands, pancreas, thyroid, ovaries, and testes. (2) “The body’s network of hormone-producing glands and organs is called the endocrine system,” explains Caroline Davidge-Pitts, MB, BCh, an endocrinologist at the Mayo Clinic College of Medicine in Rochester, Minnesota. (4) Endocrinologists are hormone doctors.

Endocrinologists Help Diagnose and Treat Hormone-Related Health Problems

Because hormones are so important to proper functioning, small problems with hormone balance can cause serious health problems. But diagnosing a hormone problem can be complicated, and treatment usually involves more than just getting more — or less — of a certain hormone. (4)

The endocrine system is a complex web of interactions. “Hormones interact with each other and with many other systems of the body, including the immune system, in ways that we don’t yet understand,” says Epstein. (1)

Here’s a look at some key hormones and what research is showing us about their diverse roles in the human body.

Common Questions & Answers

What do hormones do?
Hormones are special chemicals that travel through the bloodstream. They carry messages from the glands where they are produced to cells in different parts of the body. These chemical messages help to "turn on" or "turn off" cellular processes that control appetite, stress, blood sugar, sleep cycles, sex drive, and sexual function, to name a few.
What are estrogen and testosterone?
Estrogen is considered the female sex hormone, because it plays an important role in the development of a woman's reproductive system. Testosterone, the male sex hormone, is responsible for many of the male physical characteristics, including facial hair, muscle mass, and a deep voice. These hormones are found in both men and women.
How are hormones made?
Hormones are produced by glands that make up the endocrine system. Glands are organs that secrete substances. Major hormone-secreting glands in the body include: pituitary gland, hypothalamus, thymus, adrenal glands, pancreas, thyroid, ovaries, and testes.
What does serotonin do?
Serotonin is a hormone that doubles as a neurotransmitter. It's sometimes known as the happy chemical, as it helps regulate mood. As a neurotransmitter, serotonin is produced in the brain. But scientists are discovering that the gut bacteria in the intestines also make serotonin, suggesting an important role for serotonin in gut health.
Is there a stress hormone?
Cortisol is a hormone that helps the body respond to stress. It's called the "stress hormone," because levels of cortisol spike during high-stress situations to give your body an energy boost. Cortisol is made by the adrenal glands. Too much or too little of it for a prolonged period of time can have a negative effect on physical and mental health.

Estrogen: The Female Sex Hormone

Estrogen: The Female Sex Hormone

Estrogen is sometimes called the female sex hormone, because it is produced primarily in the ovaries and plays an important role in the development of a woman’s reproductive system during puberty. Estrogen (actually a group of hormones — estrone, estradiol, and estriol are the main types) helps to regulate the menstrual cycle in a woman’s childbearing years. (5)

Men Have Estrogen Hormones, Too

“What many people don’t realize is that the male body makes estrogen too,” says Epstein. (1) Small amounts of estrogen are secreted by the adrenal glands and fat tissue in both sexes. The male body also makes estrogen by converting testosterone into estradiol — an important hormone for bone health in both men and women, says Dr. Davidge-Pitts. (4)

Estrogen also affects brain, liver, heart, and skin health and helps to regulate metabolic processes, such as cholesterol levels. (6)

Learn More About Estrogen

Testosterone: The Main Male Sex Hormone

Testosterone is the main sex hormone in men. (7)

It plays an important role in puberty for boys. Testosterone is the hormone responsible for many of the physical characteristics we consider typically male, including facial and body hair, muscle mass, and a deep voice. (8)

Androgens Are a Class of Hormones That Includes Testosterone

Testosterone is part of a class of hormones, called androgens, that are produced primarily by the testicles in men.

But testosterone isn’t solely a male hormone. The female body also produces small amounts of testosterone in the adrenal glands and ovaries. Women need a little bit of testosterone in the mix of hormones that helps maintain mood, energy level, sex drive, and other bodily functions. (9)

Testosterone Levels Decline With Age in Both Men and Women

Both men and women experience age-related declines in testosterone. In postmenopausal women, drops in testosterone can cause a decrease in sex drive. (7) In men, low testosterone, also known as "low T," has been linked to loss of bone and muscle strength, sleep disturbances, and problems getting or maintaining an erection. (7)

Some men seek testosterone replacement therapy (TRT) for these symptoms, though the possible long-term health effects of TRT have not been well-established. (7)

Learn More About Testosterone

Cortisol: The Stress Hormone

Cortisol is a hormone that helps the body respond to stress. It’s sometimes called the “stress hormone,” because levels of cortisol spike in the body during high-stress situations to give your body a natural energy boost. (10)

Cortisol also plays a major role in metabolism by stimulating the liver to increase blood sugar and helping to convert food into usable energy. (11)

The adrenals are triangular glands that produce and release cortisol into the bloodstream. There are two adrenal glands, one on top of each kidney. (12)

Too much or too little cortisol for a prolonged period of time can have a negative effect on physical and mental health.

Learn More About Cortisol

The term “adrenal fatigue” has been used in recent years, especially by practitioners selling supplements purported to cure a host of symptoms including tiredness, body aches, nervousness, and sleep and digestive problems. “There’s no medical evidence that adrenal fatigue exists. Supplements sold for adrenal fatigue may, in some cases, be harmful,” says Davidge-Pitts. (4)

Serotonin: A Happy Chemical

Serotonin is a hormone that doubles as a neurotransmitter. It’s sometimes known as the happy chemical, as it appears to play a role in regulating mood, and low levels of serotonin in the brain have been associated with mental health. (13)

Besides the brain, serotonin is involved in the function of several different organ systems. It helps to regulate appetite and digestion, bone health, and sex. Serotonin is also a precursor to melatonin, a chemical involved in the body’s sleep-wake cycle. (14)

As a neurotransmitter, serotonin is produced in the brain. But scientists are now discovering that the intestines — specifically the gut bacteria that lines them — also make serotonin, suggesting an important role for serotonin in gut health. (13)

Learn More About Serotonin

Dopamine: A Hormone and Neurotransmitter That Helps Control Movement

Dopamine is a hormone and neurotransmitter that’s mainly involved in helping to control and coordinate movement. That’s why some drugs used to treat Parkinson’s disease — a movement disorder — boost dopamine levels in the brain. (3)

Dopamine and the Brain’s Reward System

Dopamine is a major player in the brain’s reward system, where it creates feelings of pleasure. Some street drugs hijack the brain’s reward system by acting on dopamine receptors in the brain. (15)

Outside the brain, dopamine is involved in several normal bodily functions. It helps to widen blood vessels, increase urine output, and reduce the production of insulin — a hormone involved in blood sugar regulation — in the pancreas. (16)

Learn More About Dopamine

Progesterone: The Pregnancy Hormone

Progesterone, sometimes known as the “pregnancy hormone,” is a biggie for women who are trying to conceive. Progesterone plays an important role in initiating and maintaining pregnancy by getting the uterus ready to accept and grow a fertilized egg. (17)

Progesterone is produced by the ovaries and, in pregnant women, by the placenta. The placenta secretes high levels of the hormone throughout pregnancy, causing your body to stop ovulating and preparing your breasts to produce milk. (18)

Learn More About Progesterone

Hormonal Birth Control Is Routine for Many Women

In their preteen years, young women may begin to sense the importance of their hormones and how they affect their health and wellness. At this time a young woman's body begins to change as she approaches puberty and her first menstrual period.

Later on, when they’re thinking about having sex and the possibility of pregnancy, they may consider whether to use hormonal birth control.

Nonhormonal contraception methods generally create a physical barrier between the man’s sperm and the woman’s egg(s). Hormonal contraception, on the other hand, alters the way the female body would otherwise operate.

Hormone-based methods, in general, make it less likely that a woman will release an egg, that an embryo will form, or that an embryo will be implanted.

Hormonal birth control typically includes estrogen or a form of progesterone called progestin, or a combination of the two hormones. Choices range from daily use, such as birth control pills, to long-term use, such as hormone-based IUDs, which stay in place for several years.

Other hormonal birth control options include:

  • A shot or injection, which uses progestin to keep the ovaries from releasing eggs, helps prevent pregnancy for three months at a time.
  • An implant of a progestin-releasing rod, placed in a woman’s upper arm, can help prevent pregnancy for up to four years.
  • The vaginal ring, a small circular device that is worn inside the vagina and releases progestin and estrogen, prevents ovulation and pregnancy for three weeks to a year at a time.
  • The patch, an adhesive square bandage, delivers estrogen and progestin through the skin to help prevent ovulation. This type of contraception works to prevent pregnancy for one week at a time.

Hormonal Birth Control May Not Be an Option for Everyone

Women who are obese or who have chronic health issues such as migraines or breast cancer may not be candidates for hormonal birth control methods.

Learn More About Birth Control and Contraception Options

Replacing Estrogen and Other Hormones

As women age and approach menopause, the ovaries produce less estrogen. (3) Some women take prescription medications known as hormone replacement therapy HRT) or hormone therapy (HT) to help ease hot flashes, sleep issues, or other menopausal symptoms.

A large clinical trial in the early 2000s caused alarm in the medical community when it showed a link between certain types of estrogen replacement therapy and an increased risk of breast cancer and heart disease in postmenopausal women. (19) More current analyses do not show these same risks to be associated with estrogen replacement therapy. (20) But as with any medication, there are possible side effects, and you should discuss these with your doctor.

Learn More About the Wild History of Hormone Therapy

Where to Find Hormone Information and Resources

Browse a selective list of online resources that provide information, support, and searchable databases on hormone health and hormone disorders.

Favorite Organizations and Pages for Essential Hormones Health Facts and Stats

American Society for Reproductive Medicine

This society of fertility specialists maintains a patient-focused website with easy-to-read educational pages on reproductive health topics, such as male and female infertility and assisted reproductive technologies (ART). The site also contains resources for finding a reproductive health professional.

Hormone Health Network From the Endocrine Society

The Endocrine Society is the world’s largest and most influential organization of endocrinologists (doctors who treat hormone disorders). The Hormone Health Network provides online resources for patients, including information on adrenal disorders, diabetes, thyroid problems, menopause, and transgender medicine and research. The site also contains an up-to-date physician referral directory with more than 6,500 Endocrine Society member doctors.

North American Menopause Society (NAMS)

Search for a menopause practitioner and read Q&As on perimenopause, hot flashes, hormone therapy, and other topics covered by the North American Menopause Society (NAMS), a nonprofit dedicated to promoting the health and quality of life of all women during midlife and beyond through an understanding of menopause and healthy aging.

National Institute of Mental Health

This government agency provides brochures and fact sheets in English and Spanish on common mental health disorders that explain what hormones do in the brain.

Favorite Resources for Becoming an Advocate

Partnership for the Accurate Testing of Hormones (PATH)

PATH formed in 2010 to help the clinical, medical, and public health communities improve patient care through more accurate and reliable hormone tests. PATH supports research that improves the diagnosis and treatment of hormone disorders.

National Association for Rare Disorders (NORD)

This leading nonprofit provides resources for patients and families impacted by rare diseases, including those related to hormone disorders.

PCOS Challenge From the National Polycystic Ovary Syndrome Association

Read patient stories, learn about PCOS fundraisers, and participate in groups and forums.

Favorite Hormone Health Blogs

Taking Charge of Your Fertility

Toni Weschler, author of Taking Charge of Your Fertility, blogs about natural birth control, getting pregnant with the fertility awareness method, and reproductive health.

The Period Revolutionary

Lara Briden, author of the Period Repair Manual, discusses PCOS, endometriosis, and many other menstrual cycle problems.


Cognifit is a healthcare company aimed at improving cognitive health. Their blog contains posts on all things related to brain health and neuroscience, including hormones that work as neurotransmitters.

Talking About Men’s Health

This blog was one of the top 10 men’s health blogs in 2018. Topics vary from natural remedies to help fight hair loss to what you need to know about testosterone replacement therapy.

Where To Find Hormone Health Clinical Trials

Clinical trials are medical studies aimed at preventing, diagnosing, and treating diseases. Check these resources for clinical trials on hormone disorders:

Editorial Sources and Fact-Checking


  1. Randi Hutter Epstein, MD. Phone interview. August 15, 2018.
  2. What Are Hormones, and What Do They Do? Hormone Health Network.
  3. Brain Basics. National Institute of Mental Health.
  4. Caroline Davidge-Pitts, MB, BCh. Phone interview. August 14, 2018.
  5. Estrogen (Oral Route, Paternaeral Route, Topical Application Route, Transdermal Route). Mayo Clinic. March 1, 2017.
  6. What Does Estrogen Do? Hormone Health Network.
  7. Could You Have Low Testosterone? MedlinePlus. August 14, 2018.
  8. Puberty. MedlinePlus. April 30, 2018.
  9. Therapeutic Use of Androgens in Women. Endocrine Society. October 2006.
  10. What Is Cortisol? Hormone Health Network.
  11. Curry A. The Connection Between Stress and Type 2. Diabetes Forecast. March 2016.
  12. Adrenal Glands. Johns Hopkins Medicine Health Library.
  13. Serotonin. Encyclopaedia Britannica.
  14. The Pineal Gland and Melatonin. Colorado State.
  15. Brookshire B. Explainer: What Is Dopamine? Science News for Students. January 17, 2017.
  16. Dopamine. NIH National Center for Biotechnology Information.
  17. What Is Progesterone? Hormone Health Network.
  18. Progesterone. University of Rochester Medical Center Health Encyclopedia.
  19. Writing Group for the Women’s Health Initiative Investigators. Risks and Benefits of Estrogen Plus Progestin in Healthy Postmenopausal Women: Principal Results From the Women’s Health Initiative Randomized Controlled Trial. Journal of the American Medical Association. July 17, 2002.
  20. Manson JE, Aragaki AK, Rossouw JE, et al. Menopausal Hormone Therapy and Long-Term All-Cause and Cause-Specific Mortality. Journal of the American Medical Association. September 12, 2017.


  • Gorney C. The Estrogen Dilemma. New York Times. April 14, 2010.
  • You and Your Hormones. Society for Endocrinology.
  • Chronic Stress Puts Your Health at Risk. Mayo Clinic. April 21, 2016.
  • Bergland C. Cortisol: Why the “Stress Hormone” Is Public Enemy No. 1. Psychology Today. January 22, 2013.
  • Cortisol Blood Test. MedlinePlus. August 14, 2018.
  • Dobbs D. The Depression Map: Genes, Culture, Serotonin, and a Side of Pathogens. Wired. September 14, 2010.
  • Brody J. Serotonin Syndrome: A Mix of Medicines That Can Be Lethal. New York Times. February 27, 2007.
  • Young SN. How to Increase Serotonin in the Human Brain Without Drugs. Journal of Psychiatry & Neuroscience. November 2007.
  • Davidow B. Exploiting the Neuroscience of Internet Addiction. The Atlantic. July 18, 2012.
  • Brookshire B. Dopamine Is ... Is It Love? Gambling? Reward? Addiction? Slate. July 3, 2013.
  • Is Testosterone Therapy Safe? Take a Breath Before You Take the Plunge. Harvard Men’s Health Watch. December 31, 2017.
  • Testosterone Therapy: Potential Benefits and Risks as You Age. Mayo Clinic. December 13, 2017.

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