Health Wellness 8 Signs of a Subpar Metabolism (That Have Nothing to Do With Weight) From energy to memory, here’s how a poorly functioning metabolism can manifest in the body. By Kirsten Nunez Kirsten Nunez Kirsten Nunez has been a health and fitness writer at Real Simple since 2021 and has been writing for nearly a decade. Real Simple's Editorial Guidelines Updated on December 07, 2023 Medically reviewed by Vivek Cherian, MD Medically reviewed by Vivek Cherian, MD Dr. Vivek Cherian, MD is an internal medicine physician, on-camera medical expert, and medical consultant who works to help brands like Real Simple remain abreast of current events as they relate to medicine and promote their audience's health and wellness. Learn More Fact checked by Haley Mades Fact checked by Haley Mades Haley is a Wisconsin-based creative freelancer and recent graduate. She has worked as an editor, fact checker, and copywriter for various digital and print publications. Her most recent position was in academic publishing as a publicity and marketing assistant for the University of Wisconsin Press Our Fact-Checking Process Close Photo: Ekaterina Goncharova/Getty Images Metabolism is often discussed in the context of weight gain or loss—but it involves so much more than a number on a scale. After all, metabolism occurs in every cell in the body, so whether or not it’s working optimally can manifest in myriad ways. To learn more, we asked experts to break down what a poor metabolism means, how it shows up in the body, and when to see a doctor if you notice signs of an unhealthy metabolism. What Is Metabolism? “Metabolism is the sum of reactions that take place in our body that convert food into energy,” explains Frances Largeman-Roth, RDN, registered dietitian and author of Everyday Snack Tray. It refers to how efficiently, or the rate at which, your body converts food into energy. This energy is used for every process in the body, “including digestion, breathing, repairing cells, and circulating blood and hormones,” she says. In general, metabolism is considered healthy when it’s performing those bodily functions effectively. But if the body is unable to convert food into energy efficiently or execute basic processes (like the release of insulin), metabolism is said to be unhealthy, according to Largeman-Roth. What Can Cause Unhealthy Metabolism? Heads up: There are a lot of potential factors that can contribute to an unhealthy metabolism. These underlying reasons can also range in type and severity, so the only way to pinpoint the culprit really is to see your doctor. Possible reasons behind an unhealthy metabolism include: Metabolic disorders. Many chronic conditions, such as hypothyroidism or diabetes, directly affect essential metabolic functions. These conditions can be inherited or develop later in life. Poor lifestyle habits. Over time, habits like lack of sleep, frequent dieting, and a sedentary lifestyle negatively affect your metabolism. Certain medications. Some medications, including antidepressants, antipsychotics, and beta blockers, can alter your metabolism, Largeman-Roth says. 12 Healthy Foods That Boost Metabolism Possible Signs of an Unhealthy Metabolism As metabolism regulates practically every bodily function, the signs of a metabolic issue can vary greatly. To make things even more complex, these symptoms can look different for each person, so there’s not a one-size-fits-all red flag. However, if you’d like to assess your overall metabolic health, it’s worth noting these signs and symptoms. 01 of 08 Dry, Irritated Skin While factors like cold weather and harsh cleansers can dry your skin, a wonky metabolism can also influence the skin. “Your skin has a top layer called the stratum corneum, [which] serves as a protective barrier,” explains William W. Li, MD, author of Eat to Beat Your Diet: Burn Fat, Heal Your Metabolism, and Live Longer. This barrier contains lipids, or natural body fats, that keep the skin healthy and hydrated. “Problems in body metabolism can change the skin’s ability to produce these protective lipids, and when the lipids aren’t properly formed, the skin cracks, loses water, dries out, and becomes inflamed,” Dr. Li says. 11 Signs of Inflammation Not to Ignore, According to Doctors 02 of 08 Noticeable Hair Thinning It’s no secret that thinning hair is common with age or after highly stressful events, but losing more hair than usual may indicate an unhealthy metabolism. The exact mechanisms will depend on the underlying cause, but some possible causes include poor blood flow and nutrient deficiency caused by metabolic dysfunction. 03 of 08 Frequent Headaches “An unhealthy metabolism usually results in abnormal insulin and glucose control, which can cause migraine headaches,” Dr. Li says. For example, metabolic syndrome—which consists of high blood sugar, high cholesterol, large waist size, and high blood pressure—can cause headaches due to the narrowing of blood vessels related to high blood pressure, he explains. 04 of 08 Digestive Discomfort As metabolism is needed for proper digestion, a metabolic issue can mess with your system’s ability to efficiently digest food. “You may feel like food just sits in your stomach and doesn’t move through as quickly as it used to,” Largeman-Roth says. 05 of 08 Inexplicable Exhaustion Again, the primary purpose of metabolism is to create energy for your body. Thus, if something is amiss with your metabolism, you’ll feel bogged down and fatigued. This might be even more obvious during more energizing activities, like exercise, as a healthy metabolism should be flexible enough to meet increased energy needs. 06 of 08 Being Constantly Too Cold (or Hot) Your body’s ability to regulate its temperature relies on—you guessed it—your metabolism. But if something is off in the metabolic department, you might always be colder or warmer than those around you. In other cases, a metabolic disease could affect specific bodily functions needed to control your temperature. For example, diabetes can damage blood vessels throughout the body, according to Dr. Li. This can make it difficult for blood vessels to dilate (or widen), which is needed for proper blood flow, circulation, and keeping you warm. 07 of 08 Poor Memory and Brain Performance Over time, an off-kilter metabolism can lead to whole body inflammation. If this eventually affects the brain, poor memory may develop, says Dr. Li. Some conditions (like diabetes) could also mess with the small blood vessels that nourish the brain. “When these blood vessels are damaged, brain function (including cognitive performance and memory) can decline,” explains Dr. Li. 08 of 08 Low Mood In addition to poor memory, brain inflammation caused by metabolic issues may lead to a low mood. That’s because inflammation can disrupt signals between neurotransmitters—i.e., chemical messengers that regulate everything from feelings to hormones—potentially increasing the risk of depressive symptoms. And while a low mood doesn’t automatically indicate a metabolic problem, it’s certainly worth considering if you have other symptoms on this list. When to See a Doctor Again, there are many possible factors that can contribute to a poor metabolism; and many of the above signs can be related to an issue other than metabolism. With that in mind, it’s impossible to narrow metabolism changes down to one red flag, but if you experience any of those mentioned above, Dr. Li recommends talking to your doctor. They can order tests to determine if an underlying illness is affecting your metabolism, along with the best treatments, therapies, or lifestyle changes for your situation. 12 Ways to Boost Energy Without Sugar or Coffee Was this page helpful? Thanks for your feedback! Tell us why! Other Submit Sources Real Simple is committed to using high-quality, reputable sources, including peer-reviewed studies, to support the facts in our articles. Read our editorial guidelines to learn more about how we fact check our content for accuracy. Michigan State University Extension. Understanding your metabolism. Washington University in St. Louis. Endocrine and metabolic disorders. Rosso JD, Zeichner J, Alexis A, Cohen D, Berson D. Understanding the epidermal barrier in healthy and compromised skin: clinically relevant information for the dermatology practitioner: proceedings of an expert panel roundtable meeting. J Clin Aesthet Dermatol. 2016;9(4 Suppl 1):S2-S8. Thom E, Wadstein J, Kingsley D, Thom EW. Metabolic syndrome, cardiovascular disease and the hair growth cycle: addressing hair growth disruptions using Nourkrin with Marilex as a proteoglycan replacement therapy: a concise review. Ann Dermatol Res. 2018; 2: 001-007. doi10.29328/journal.adr.1001004 Arca KN, Halker Singh RB. The hypertensive headache: a review. Curr Pain Headache Rep. 2019;23(5):30. doi:10.1007/s11916-019-0767-z Smith RL, Soeters MR, Wüst RCI, Houtkooper RH. Metabolic flexibility as an adaptation to energy resources and requirements in health and disease. Endocr Rev. 2018;39(4):489-517. doi:10.1210/er.2017-00211 Shrestha DC, Acharya S et al. Modeling on metabolic rate and thermoregulation in three layered human skin during carpentering, swimming and marathon. Applied Mathematics. 2020: 11(8). doi:10.4236/am.2020.118050 Kenny GP, Sigal RJ, McGinn R. Body temperature regulation in diabetes. Temperature (Austin). 2016;3(1):119-45. doi:10.1080/23328940.2015.1131506 Qiu W, Cai X, Zheng C, Qiu S, Ke H, Huang Y. Update on the relationship between depression and neuroendocrine metabolism. Front Neurosci. 2021;15:728810. doi:10.3389/fnins.2021.728810