You’ve probably heard people blame their inability to lose weight on their slow metabolism. But what you might not have heard is what the metabolic process really is: how your body converts what you eat and drink into energy. And one of the biggest factors in this daily cycle? Your thyroid. As the Obesity Action Coalition explains, the butterfly-shaped thyroid gland produces hormones that “play a significant role in your metabolism and in energy regulation in the body.”
So what happens when this gland stops functioning properly? Well, as some 20 million Americans can tell you, both overactivity and underactivity in your thyroid can lead to some serious complications, ranging from depression and mood swings to dry skin and brittle nails. If you feel like your metabolism is out of whack and think that you might be dealing with thyroid disease, then read up on the signs your metabolism isn’t functioning properly.
You have migraines
Hypothyroidism is a condition in which a person’s thyroid gland doesn’t produce enough of the hormones crucial to metabolizing food—and because of this, people with untreated hypothyroidism have metabolisms that work at a slower speed.
But how are you supposed to know whether your thyroid—and therefore your metabolism—isn’t functioning properly? Well, one 2019 study published in the journal Cephalalgia found a link between migraines and hypothyroidism. Specifically, the study found that just 13 percent of subjects without hypothyroidism had migraines, compared to a staggering 46 percent of patients with the thyroid disease.
You have dry skin
Migraines aren’t the only thing caused by thyroid disorders like hypothyroidism. Rather, the American Academy of Dermatology (AAD) notes that “many signs and symptoms of thyroid disease develop on the skin, hair, and nails.” One such symptom is “dry, pale, and cool skin.” So if you ever find that your face is looking flakier than usual, you should talk to your primary care physician about the possibility of a thyroid disorder.
Your hair is thinning
If you’re wondering whether your metabolism has slowed down, just take a look at your hair follicles. According to the AAD, people with thyroid diseases tend to experience hair loss in patches—and as for the hair that remains on their head, it tends to be “coarse, dull, dry, and brittle.”
You have brittle nails
Do your nails look dry and weak no matter what you do to revive them? That could be your thyroid—and metabolism—talking. The AAD notes that nails that are “thick, dry, and brittle with visible ridges” are just one of the signs of thyroid disease. Similarly, nails that take a long time to grow back can also be a sign of a slow metabolism.
You’re gaining weight inexplicably
People with hypothyroidism have underactive thyroids that aren’t as efficient at assisting the metabolic process. As such, the American Thyroid Association notes that one of the signs your metabolism is slow is unexplained weight gain—and the worse your thyroid condition, the more severe your weight gain will be. Thankfully, this weight fluctuation is typically just an “excess accumulation of salt and water,” meaning that it’s easy to shed once the underlying condition is treated.
You’re experiencing mood swings
Moodiness, believe it or not, can be one of the signs your metabolism is slow. But how does this happen? Well, one 2007 study presented at the Annual Meeting of Society of Nuclear Medicine found that “hypothyroid patients—compared to healthy individuals—have decreased metabolism in special parts of the brain that are responsible for processing information,” Waltraud Eichhorn, a nuclear medicine physician in Germany and co-author of the study, said in a press release.
Depression is another mood change that can be a sign of a slow metabolism. Indeed, one 2019 review published in Frontiers in Endocrinology analyzed more than 103,000 patients from seven studies and found that people with subclinical hypothyroidism have a 78 percent elevated risk of depression compared to those with fully functioning thyroids.
Your forgetfulness could be a natural side effect of aging, sure, but it could also be one of the signs your metabolism isn’t functioning properly. According to the nonprofit British Thyroid Foundation, one of the common mental health issues associated with both an underactive thyroid and an overactive thyroid is short-term memory lapses.
Fatigue plays a fairly prominent role in hypothyroidism. And one 2018 study published in the journal Frontiers in Physiology found that it can also be seen in individuals with hyperthyroidism, a thyroid issue characterized by an overactive thyroid and an overactive metabolism. This is because the thyroid condition puts the hypothalamic-pituitary-thyroid (HPT) axis—the part of the neuroendocrine system that controls the body’s metabolic function—into overdrive. And eventually, the body just can’t keep up.
You have an irregular heart rhythm
A too-fast metabolism and an irregular heart rhythm go hand in hand. That’s according to a 2012 study published in the journal BMJ, which found that the less thyroid stimulating hormone (TSH) a person had, the more likely they were to have atrial fibrillation. Since low levels of TSH is a key marker of hyperthyroidism, this landmark study is evidence of the fact that an irregular heartbeat is one of the signs of an overactive metabolism.
You have bowel movement issues
“Both thyroid hormone excess and deficiency can have similar digestive manifestations, such as diarrhea,” notes one 2009 study published in the World Journal of Gastroenterology. However, diarrhea isn’t the only way in which a thyroid problem can manifest. As the study authors note, both hyper- and hypothyroidism have “numerous gastrointestinal manifestations,” and so any and all bowel movement issues can be seen as a potential sign of metabolic issues.
You have trouble concentrating
Are you having trouble concentrating on your work? That may be an indication that your metabolism is out of whack, according to a paper published in the Lancet journal. The authors of the research note that “poor concentration”—in addition to other things like disturbed sleep and nervousness—are some of the neuromuscular signs of excess thyroid hormone in the bloodstream, i.e. hyperthyroidism.