What Exactly Are Hormones? Here’s What You Need to Know About Their Critical Roles

Amanda Loudin
Medically Reviewed
May 5, 2021

Your hormones are the boss of your body. With over 50 circulating hormones, these ones matter most to overall health.

If your body had a roadmap from one part to another, it would be the endocrine system, the group of glands and organs that produce hormones. And on those roadways, you’d find your hormones moving between your body’s adrenal glands, pituitary gland, pineal gland, thyroid , pancreas, and sex organs, and a wide variety of other organs and tissues. So, what are hormones, anyway? Hormones are chemical messengers that connect various body parts and allow them to communicate with each other.

That means that your hormones play a big role in overall health . In fact, there are more than fifty hormones in the body, each acting to regulate different processes. Among those processes: growth, energy production, blood sugar levels, metabolism, and more.

Key hormones include insulin, melatonin, the sex hormones such as estrogen and testosterone, thyroid, ghrelin, and many others. With such a central and important role in the body, your goal should be to keep them all in balance, says Debra Hummel, DNP, ANP-C , a nurse practitioner with Parsley Health. “Each hormone has a role in regulating the body’s organ cells and tissues,” she says. “We want to keep them in balance to feel our best.”

What are the most important hormones?

With more than 50 hormones at work in your body, some are going to have bigger roles than others. Here are some of the key ones to know and the job they carry in keeping you healthy:


Where it’s made: adrenal glands

What it does: Cortisol ’s main role is to help your body manage stress and regulate the immune response (think “fight or flight”). Cortisol will increase your heart rate, blood pressure, and energy levels so that you can take on what your body perceives as a threat. In order to do this, the hormone shuts down other less important processes, like regulating your metabolism.

Why it matters: “This is the ‘mother’ hormone,” explains Hummel. “When it gets out of balance, it has a trickle-down effect on other hormonal systems in our body.” If you find yourself living in a perpetual state of stress, your body is producing excess cortisol, and regular bodily functions can be interrupted. There are several health risks from chronic stress, as long-term elevated cortisol has been associated with high blood pressure, diabetes, obesity, and osteoporosis. It may also impact fertility .


Where it’s made: enigmatic pineal gland

What it does: Often thought of as the “sleep hormone,” melatonin is also nicknamed the “hormone of darkness.” It is activated in response to darkness/nighttime, one of its main jobs is to signal your body to go to sleep and stay asleep .

Why it matters: Disruptions to melatonin can impact your ability to sleep, which has negative health impacts. Poor sleep has long been associated with a host of detrimental impacts on wellbeing. Specifically, sleep deprivation can increase our risk of heart disease, injury, depression, mood disorders, and diabetes , while decreasing immune activity, gut health , and cognitive function. Common causes of lower melatonin levels include jet lag, working swing shifts, or too much cortisol.

Leptin and ghrelin

Where they’re made: fat cells and stomach lining

What they do: Leptin and ghrelin have large roles in energy balance via the digestive system—they are in control of your hunger signals . Leptin is the long-haul hormone of the two, acting to suppress food intake and induce weight loss. Ghrelin, by contrast, is a fast-acting hormone, with the job of signaling hunger and the need to eat. Think of them as an appetite suppressant (leptin) and appetite stimulant (ghrelin). Both are secreted in a rhythm, originating in the hypothalamus of the brain.

Why they matter: These digestive hormones can be influenced by low levels of melatonin. “If you’re not getting enough sleep, it can interfere with your stomach hormones and lead to sugar cravings ,” explains Hummel. And as with melatonin, many digestive issues stem originally from too much cortisol in the body. And digestive issues can signal a host of health issues .

Estrogen, progesterone, and testosterone

Where they are made: adrenal glands and the gonads

What they do: The female (estrogen and progesterone) and male (testosterone) sex hormones have a major influence on a number of functions within the body, not just reproduction. They can impact moods, pain reception, blood pressure regulation, and cognitive function, among other things, varying from one gender to the other.

Why they matter: Estrogen and progesterone are steroid hormones and have important roles in preparing the body for pregnancy . They also help with building bone, helping with the efficient use of fat as a source of energy, and benefitting the cardiovascular system by blocking plaque formation in the blood vessels.

Testosterone, while primarily considered the male sex hormone, is also part of the female hormone makeup. In females, it influences stamina and libido, along with ligament, muscle, and bone health. In men, testosterone regulates libido, muscle mass and strength, and red blood cell and sperm production. As with other hormones, when the sex hormones are unbalanced—often a result of chronic stress and cortisol levels—the body reacts with a host of symptoms. These can range from irregular menstrual cycles in women, decreased libido, mood swings, and more. In men, low testosterone can lead to decreases in lean body mass, fatigue , decreased energy, and lower sex drive.

Thyroid hormones

Where they’re made: hypothalamus and pituitary

What they do: Similar to cortisol, thyroid hormones play an outsized role in your overall health. In fact, these hormones can play a backup role to cortisol. “When cortisol is out of balance, the thyroid can be affected,” says Hummel. The main thyroid hormone is TSH—thyroid-stimulating hormone—which assists the thyroid gland in producing its other hormones, T3 and T4. This set of hormones is in charge of a host of functions, including temperature regulation, weight, brain function, digestion, and more.

Why they matter: The thyroid affects metabolic activity (or how your body uses energy), your heart, and your bones, but it can really have an influence on every function and organ in the body to some degree. That means, if something is off, it could have a ripple effect. Thyroid health also plays a large role in fertility and reproductive health .

Thyroid disorders are fairly common, and often present in females post-partum. Hypothyroidism, hyperthyroidism, goiters, and sometimes thyroid cancer all stem back to an imbalance of the three hormones. Symptoms of hypothyroidism include unexpected weight gain, low energy levels, and sometimes, hair loss. Hyperthyroidism, by contrast, is an overproduction of thyroid hormones and can result in weight loss and a high heart rate.


Where it’s made: pancreas

What it does: Insulin is a peptide hormone, and it helps your body regulate glucose levels in the bloodstream. As you eat and glucose levels rise, the pancreas releases insulin, binding to receptors on cell surfaces, leading to glucose processing.

Why it matters: When most people think of insulin, they think of diabetes, which is a condition where the body produces little or no insulin (Type 1) or inadequate amounts of insulin (Type 2). The former is a genetic condition, the latter a lifestyle condition. There is also the increasingly common condition of pre-diabetes , where insulin resistance shows up as a warning signal.

When hormone balance is lost

The roles that each of these hormones plays is unique, and when any become unbalanced they often share similar symptoms:

  • Fatigue
  • Headaches
  • Poor digestion
  • Weight gain/loss
  • Anxiety
  • Bloating /water retention
  • Heavy/irregular periods
  • Dizziness
  • Mood swings

More often than not, it’s chronic stress catching up with you, meaning your cortisol levels are too high and trickling down to every other hormone in your body. If left untreated, this can result in hypothyroidism, fertility issues, insomnia , diabetes, and more.

There are other lifestyle behaviors that contribute to hormone imbalance, too: “Things like alcohol consumption or eating too many processed foods can play a part in hormone imbalance,” says Hummel. “Or if you’re tossing and turning at night, not getting adequate rest, it can throw off hormones.”
If you suspect a hormone imbalance, hormonal testing (which can be done at Parsley Health ) can give you a clearer picture of your hormones and confirm any irregularities. Tests will evaluate blood, urine, or saliva, and pinpoint what you’re lacking where.

How to restore hormone balance

Fortunately, treating hormone imbalances can often be accomplished with a few, easy holistic lifestyle changes:

Adopt a whole foods diet

Diet is a good starting place , says Hummel. “I’m a believer in whole foods first,” she says. “Aim for a mostly plant-based diet and make sure to include plenty of fiber .”

Avoid excessive alcohol and caffeine

Avoiding excessive alcohol consumption—especially if you use it to wind down—is a good step, too. And the same with caffeine, only in reverse. “If you need to drink lots of coffee to function, it means you’re not getting enough sleep,” says Hummel.

Get moving

Focus on getting enough exercise, too. “We’re not meant to be sedentary,” says Hummel. “You want to get in at least 20 minutes of exercise, like walking, each day. Even better are high interval training sessions, which get your heart rate up, and then you recover and repeat.” Here’s a primer on the hormones you can balance using exercise .

But also relax when needed

Consider relaxing activities, too, like yoga and meditation . “These help put us in a parasympathetic phase and balance out our hormones ,” explains Hummel. “Focus on getting enough sleep each night, which can make a big difference, too.”

Try supplements

What about supplements ? Hummel suggests turning to them when other measures have failed but doing so with a dose of caution. “Food and lifestyle measures come first, but sometimes you may need to supplement with a good multivitamin or even adaptogens to balance your body’s needs,” she says. “But do your research to make sure it’s a good one—often they are filled with things you don’t need.”

At the end of the day, many small steps toward a healthier lifestyle can add up and make a difference, bringing your key hormones back to homeostasis. If you’re looking for personalized guidance around lifestyle choices to balance your hormones, Parsley can help . “When your hormones are in balance, you can live your best life,” says Hummel.

Amanda Loudin

Amanda Loudin is an award-winning freelance writer with a focus on health and science. Visit www.amanda-loudin.com to learn more.

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