Medically reviewed on February 15, 2022 by Jordan Stachel, M.S., RDN, CPT. To give you technically accurate, evidence-based information, content published on the Everlywell blog is reviewed by credentialed professionals with expertise in medical and bioscience fields.
Sometimes, hormones get a lot of blame when something goes wrong in the body, but they don’t often receive praise when the body functions smoothly. This is because we don’t give our body’s inner physiology much thought until we feel poorly.
While they’re seldom cheered, hormones are critical to good health. They regulate many of the body’s functions, including metabolism. In fact, eight key hormones help the body (and the metabolism) function properly—insulin, leptin, triiodothyronine, cortisol, ghrelin, progesterone, testosterone, and estrogen.
Metabolism is a complicated process. Learn more about the basics of hormonal regulation below (and consider learning more about the at-home Metabolism Test).
Metabolism includes all the processes the body goes through to convert the food you eat into energy. It involves several steps:
Metabolic processes rely on enzymes and hormones, which cause the reactions needed to convert food into usable energy. When hormone levels are unbalanced, metabolic functions can misfire. This can cause energy levels to dip and overall health to suffer.
One thing to keep in mind is that metabolism isn’t the only factor that controls weight. It’s just one part of the body’s weight management system. This system also includes hormones both closely tied and tangentially related to metabolic function.
However, if the endocrine system is not functioning optimally, energy levels and the ability to get through daily tasks may deteriorate.
So, the answer to the question “What hormone regulates metabolism?” is complex. The answer must take all the hormones into account that are responsible for hunger, metabolic rate, and other functions. To that end, the hormones that impact metabolism most closely include:
Insulin – Insulin is produced by the pancreas. From there, it’s released into the body, where it helps convert carbohydrates into blood glucose. The blood glucose is then used for energy. The right amount and usage of insulin in the body is critical for survival. For example, type 2 diabetics can’t properly use insulin, while type 1 diabetics don’t produce enough insulin.
Leptin  – Leptin is made by fat cells and is responsible for sending the “I’m full” message to the brain. The right balance of leptin in the body helps you to know when you’re hungry and when you’re full. If insulin levels are too high or if you have chronic inflammation, the body’s ability to react to the release of leptin may be impaired. This can lead to overeating and/or rapid weight gain.
Triiodothyronine  – Triiodothyronine, or T3, is one of the hormones produced by the thyroid gland. It has several roles, including setting metabolic rate, digestive functions, and brain growth. It also impacts muscle function and skeletal development.
Cortisol – Cortisol is also known as the stress hormone. The adrenal glands release cortisol when they sense stress. Sometimes this is a good thing—you want your body to respond to inflammation when threatened. Cortisol also helps regulate the metabolism and blood sugar levels. However, consistently spiked cortisol levels can increase appetite and cause overeating.
Ghrelin – Ghrelin is produced by the stomach and tells the brain that you need food. High levels of ghrelin will cause you to feel hungry more often. In those who are overweight or obese, the ghrelin and leptin systems often don’t work optimally, and the hormones aren’t as powerful when released.
Progesterone  – Progesterone helps promote the storage of glycogen in the liver. This is an important key to balancing blood sugar levels. The carbohydrates you consume are converted to glucose. Excess glucose is taken from the bloodstream and converted to glycogen in the liver. If this step doesn’t occur, the excess glucose is instead converted to body fat.
Testosterone  – People with more lean muscle mass tend to have more effective metabolisms than those with more body fat. Muscle uses more energy than fat so the more muscular you are, the more calories you might need. Testosterone helps increase the production of proteins that help to build muscle mass. It also regulates how the body uses fat for energy.
Estrogen – Both men and women produce estrogen. However, women typically have higher levels than men. Estrogen promotes fat storage and is necessary for the regulation of the woman’s reproductive system. When estrogen levels are too high or too low, the body may store excess fat, leading to weight gain and/or lethargy.
Along with hormones, several other factors determine metabolic rate. These include:
Age – As you get older, metabolic rate naturally slows as part of the aging process .
Physical activity level – Exercise and metabolism are correlated. The more active you are, the more energy the body needs, which can affect the efficiency of metabolism and hormonal regulation.
Weight and body composition – In a similar vein, if weight is higher (either due to fat or muscle mass), your body may require more calories.
Food consumption – Eating foods with high levels of protein can stimulate metabolism.
Environment – If you live in a colder climate, your metabolic rate may be faster than individuals who live in warmer conditions.
Physical condition – Women who are pregnant or breastfeeding will see an increase in their metabolic rate.
Therefore, along with monitoring hormone levels, you must consider these other components when trying to determine if the metabolism is functioning optimally.
Metabolic testing is done using several methods. You can go to a gym, fitness center, or even a university health center to get a basic estimate for how many calories your body uses at rest and/or when active [6, 7]. Test conductors measure oxygen consumption, heart rate, and endurance capacity to analyze:
You can also gain insight into metabolism through a blood test. A blood test will measure the levels of three key hormones to determine if the body is running at maximum efficiency. These tests can be performed in a healthcare provider’s office or with an at-home testing kit.
An at-home metabolism test lets you collect a small blood sample and send it to a certified lab for testing. The lab will provide you with information about hormones, including:
Cortisol – High levels of cortisol often indicate stress. Whether you have work, family, or personal problems, stress can wreak havoc on normal metabolic functions. Cortisol is also needed for glucose production. Without it, you can suffer from low energy availability.
Free testosterone – Testosterone, a sex hormone, is necessary for the body to build and maintain muscle. As you know, muscle requires more daily energy than fat, so having the right amount of testosterone helps the body use calories more efficiently.
Thyroid hormone – The thyroid gland is also a critical piece of the metabolic puzzle. Measuring the levels of thyroid-stimulating hormone tells you whether your thyroid is over or under-active.
You’ll collect your sample by following the test kit’s instructions. Then, after the lab has processed it, you’ll receive results digitally. The results will provide you with general information about hormone levels.
This is an excellent way to gain insight into metabolic functions. It can also help determine if it’s time to make an appointment with your healthcare provider to help balance hormone levels.
You can’t control every factor related to your metabolism. However, that doesn’t mean you’re powerless. There are things you can do to ensure that you’re maximizing both the speed and effectiveness of your metabolism. These include:
Increase physical activity – Your body uses more energy when you exercise. Exercising also helps build muscle, and muscle helps increase the amount of energy your body uses, even at rest.
Eat a healthy diet – The old adage of “you are what you eat” is certainly true when it comes to your health. A diet rich in fresh produce, whole grains, proteins, and healthy fats will give you the energy you need. It will also help prevent inflammation and/or other issues that can cause hormones to malfunction.
Manage stress – High stress levels can cause cortisol levels to skyrocket. In turn, you might feel hungrier and overeat. This can lead to weight gain and/or increased risk for many chronic diseases, including heart disease, diabetes, and/or high blood pressure.
Get enough sleep – Have you been hungry all day after a sleepless night? When you don’t sleep, you lack energy. This leads the body to think that you need more food. You’re also more likely to make unhealthy food choices when you’re overtired. Sleep is when your body gets the opportunity to reset from the day. When you miss out on sleep, the entire body suffers.
Staying on top of your health by practicing good habits is the best way to maximize your metabolism. If you feel like something is off, you should check your hormone levels and make an appointment with your healthcare professional.
Have you been feeling sluggish, and you suspect your hormones are to blame? While many factors can cause energy levels to dip, hormones are frequently part of the problem. Checking hormone levels can give you both insight into your body’s inner workings and peace of mind.
At Everlywell, our at-home Metabolism Test is an easy-to-use first step to getting hormone levels on track. Your confidential results from our certified lab will arm you with data to share with your healthcare provider. Instead of feeling tired and lethargic, you can correct the imbalance and get your energy back.
1. The truth about metabolism. Harvard Health. URL. Accessed February 15, 2022.
2. Hormones and the Endocrine System. Johns Hopkins Medicine. URL. Accessed February 15, 2022.
3. Havel PJ. Update on Adipocyte Hormones: Regulation of Energy Balance and Carbohydrate/Lipid Metabolism. Diabetes. 2004;53(Supplement 1):S143-S151.
4. Mansourian AR. Metabolic pathways of tetraidothyronine and triidothyronine production by thyroid gland: a review of articles. Pakistan journal of biological sciences: PJBS. 2011;14(1):1-12.
5. Kalkhoff RK. Metabolic effects of progesterone. American Journal of Obstetrics and Gynecology. 1982;142(6 Pt 2):735-738.
6. Welle S, Jozefowicz R, Forbes G, Griggs RC. Effect of testosterone on metabolic rate and body composition in normal men and men with muscular dystrophy. The Journal of Clinical Endocrinology & Metabolism. 1992;74(2):332-335.
7. Metabolic Testing. UC Davis Sports Medicine Program. URL. Accessed February 15, 2022.