By Sandra Gordon

The hormones in your body are powerful chemicals, affecting much more than pregnancy or your ability to conceive. Released into your bloodstream by specialized glands or organs, these purposeful messengers influence everything from the speed at which you feel pain to the rate you burn calories. Tiny amounts of hormones can make big things happen. Here’s a rundown of some of the most important hormones and how they can help or hinder your health. 

SEX HORMONES: Estrogen & Progesterone 

Main functions: To regulate your reproductive cycle and make the uterine environment cushy in case a fertilized egg is implanted. 

How they work: At the beginning of your menstrual cycle, the levels of estrogen and progesterone produced by the ovaries drop, causing the uterine lining (endometrium) to be shed. As your cycle progresses, your ovaries produce more of both hormones, with an estrogen peak produced midcycle, when an egg is released from an ovary (ovulation). If the egg isn’t fertilized and implanted in your uterus, estrogen and progesterone levels will ebb around day 28, signaling the start of a new cycle. If a fertilized egg does implant in your uterus, estrogen and progesterone levels hold steady to maintain optimal conditions for an embryo to develop in the uterus. 

The downside: Progesterone is to blame for premenstrual symptoms such as temporary water retention and the resulting weight gain. “Progesterone causes your circulatory system to slow down,” explains obstetrician/gynecologist Jayshree Vyas, MD. In other words, the whole process of taking in water and getting rid of it that the cells normally go through becomes sluggish. As a result, you retain water. 

Did you know? Besides its reproductive duties, estrogen plays a role in osteoporosis prevention; it increases calcium absorption to help you maintain enough calcium in your bones. Estrogen also protects us against heart disease, increasing the “good” HDL cholesterol, while keeping the artery-clogging “bad” cholesterol in check. This is why premenopausal women suffer fewer heart attacks than men. At menopause, however, when estrogen and progesterone levels drop, your risk of osteoporosis increases, and you lose your resistance to heart disease. By age 65, the risk of heart attack is as great for women as for men. 

There is also substantial evidence that estrogen may enhance brain function and memory.

ENERGY HORMONE: Insulin 

Main function: Produced by the pancreas, an organ that lies horizontally behind your stomach, insulin helps your body utilize glucose, a form of sugar. 

How it works: As soon food enters your mouth, an impulse from your brain signals to specialized beta cells in your pancreas that food is on the way, says endocrinologist Priscilla Hollander, MD. When food hits your stomach, it’s broken down and converted into glucose, which gets absorbed into your blood. To actually penetrate your fat and muscle cells, and provide energy for your body, glucose needs to be escorted by insulin. “Fat and muscle cells have receptors on them that act like a lock,” explains Hollander. “Insulin is the key that lets glucose in.” 

The downside: It’s also insulin that causes excess glucose to be converted into fat and stored on your hips. 

Did you know? Type 1 diabetes is when your pancreas stops making insulin completely. This inherited autoimmune disorder is usually diagnosed before age 30. Type 2 diabetes is when your pancreas stops producing enough insulin or your body’s cells stop absorbing the insulin your pancreas makes. In either case, your cells won’t get the energy they need to fuel your body. 

According to the American Diabetes Association, roughly 34.2 million Americans have diabetes, and one-third of them don’t even know it.

Untreated Type 1 or Type 2 diabetes can lead to severe complications such as blindness and kidney failure. Might you be diabetic? To find out for certain, see your doctor if you have any of the following symptoms: the need to urinate often, constant thirst, unexplained weight loss, weakness or fatigue, blurred vision, tingling or numbness in your hands or feet, many infections, or slow healing of cuts and wounds. 

STRESS HORMONES: Noradrenaline & Cortisol 

Main function: Noradrenaline and cortisol are two significant hormones secreted by your body’s adrenal glands, which are situated on top of your kidneys. Noradrenaline is also made at other strategic locations: your heart, brain and blood vessels. Although your body makes both hormones all day long, they are major players in your body’s fight or flight response, acting as the radar for sudden fear and stress. 

How they work: Get in the way of an oncoming car and these first-line defenses jump-start your heart to make it work harder, helping it increase blood flow to your extremities so you can flee to safety. After these hormones do their job, they’re metabolized in the liver and excreted through the kidneys. 

The downside: Acute stress can cause your body to make too much noradrenaline and cortisol. Both hormones are at full throttle, for example, when you’re having a heated argument. 

Stress ignites a hormonal chain of events that can lead to a host of medical problems, such as stomach ulcers, chronic back pain, even heart attacks.

Did you know? Without noradrenaline, messages from your nervous system wouldn’t get relayed throughout your body. You wouldn’t jump out of the path of that car, for example, or pull your hand away from a hot surface. Without cortisol, the DNA in almost every cell in your body wouldn’t get the messages it needs and you could not survive.