When it comes to your endocrine system, your thyroid is mission control. This butterfly-shaped gland at your throat oversees the way your body uses energy—better known as metabolism—and affects a variety of organs and functions throughout your entire body. The hormones it produces can influence your mood, digestion, heart rate, weight, skin, breathing, and more. 

The trouble is, your thyroid has to play the role of Goldilocks, always striving to keep the balance between too much and too little hormone production—and, all too often, this delicate balance can become disrupted. If your thyroid produces too many hormones, you end up with a condition called hyperthyroidism—but too few of them lands you with the opposite condition, hypothyroidism. 

Both types of thyroid dysfunction can come with some unpleasant symptoms that fly under the diagnostic radar. Dramatic changes to your health like major weight fluctuations or always feeling hot or cold are signs to make a beeline for the doctor’s office, but more subtle signs can point to thyroid dysfunction, too. In fact, experts say that these seven surprising symptoms could mean something is up with your hormone HQ.

1. Constipation

Is it that you’re not eating enough fiber—or something else? Constipation often gets chalked up to poor dietary habits, but it might have more to do with hormones than whole grains. “When the thyroid gland is underactive and doesn’t produce enough thyroid hormones, it can slow down various bodily processes, including digestion and bowel movements,” says Florence Comite, M.D., a physician with multiple specialties in endocrinology and founder of the Center for Precision Medicine and Health. “Constipation is typically the most common sign of an underactive thyroid gland.”

2. Trouble Sleeping

*Yawn!* Tossing and turning at night is super-common in the general population—about 10 to 30 percent of us have insomnia—but for some, sleeplessness isn’t just a stress issue. Instead, the thyroid may hold the keys to your sleepytime fate.

Read More: 7 Foods That Are Good For Your Thyroid

In fact, one 2021 study found that both hyper- and hypothyroidism were associated with poor sleep. In the case of hyperthyroidism, issues like tremors, anxiety, and irritability kept people awake, while people with hypothyroidism had disrupted sleep from muscle and joint pain, cold intolerance, and (again) anxiety.

3. Brittle Hair and Nails

Your thyroid can affect everything from your head to your toes—or, more accurately, from your hair to your toenails. Brittle hair and nails are often related to thyroid issues, especially an underactive thyroid. 

“The thyroid is the metabolic controller in the body, and can up- and down-regulate metabolic pathways,” explains naturopathic physician Alexa Neynaber, N.M.D., of Virasoap Natural Medicine. “Hypothyroidism tends to cause slower metabolism, which can be seen over time in things that grow like hair and nails.” 

According to Neynaber, thyroid-related nutrient deficiencies can make this worse. “I would argue that often it’s the associated deficiencies in B vitamins and trace minerals such as zinc and selenium, which go hand in hand with thyroid disorders, that contribute here,” she says.

4. Mood Changes

So many things in life can cause changes to mood, from losing your dream job to simply not getting enough omega-3s. Still, if you’re noticing new and unusual symptoms of anxiety or depression, it’s worth exploring whether your thyroid could be involved in the shift. Research shows that feel-good hormones like somatostatin and serotonin influence the hypothalamus-pituitary-thyroid axis, and that hypothyroidism is thus linked with depression. 

Read More: 5 Signs You Need More Omega-3s

According to Neynaber, an out-of-whack thyroid can throw off nutrient levels that affect mood, too. “Hypothyroidism is commonly associated with iron deficiency in many of my patients, and many studies have associated low iron and low mood, especially in women,” she says.

5. Brain Fog

Brain fog is another issue with all sorts of modern-day causes, but an underactive thyroid can certainly put a serious dent in your sense of mental clarity. “Thyroid dysfunction, specifically hypothyroidism, can contribute to brain fog symptoms like fatigue, forgetfulness, and difficulty focusing,” says Comite. 

Read More: 10 Natural Ways to Eliminate Brain Fog 

If you think your thyroid could be causing foggy thinking, it may not be all in your head! A 2022 study revealed that patients treated for hypothyroidism frequently had brain fog. In fact, a whopping 79 percent reported experiencing it frequently! Getting more rest was the most helpful antidote, so that’s worth prioritizing, in addition to working with a healthcare professional to support thyroid function.

6. Dry Eyes

When you think about the body parts affected by hormones, you might not consider your eyes—but the thyroid can absolutely influence their hydration status. “Dry eyes can be a symptom of thyroid dysfunction, specifically hypothyroidism or autoimmune thyroid conditions such as Graves’ disease or, to a lesser extent, Hashimoto’s thyroiditis,” Comite says. In these conditions, thyroid antibodies make the immune system attack the tissues around the eyes, leading to dryness. 

7. Hair Loss

Every time you run your hand through your hair, does it seem like you come away with a clump of strands between your fingers? Thyroid problems could be to blame. Because hormones triiodothyronine (T3) and thyroxine (T4) are involved in your natural cycle of hair production, tweaks to their equilibrium can cause your hair to become thin or shed more rapidly than normal. That’s right, this can occur in both hypo- and hyperthyroidism.

What to Do If You Think You Have Thyroid Issues

First things first, if you suspect that these or any other symptoms are to do with an over- or underactive thyroid, it’s critical to see your healthcare provider. A simple blood test can reveal your levels of T3 and T4, as well as thyroid-stimulating hormone (TSH). This can give you the answers you’re seeking about whether a hyped-up or pooped-out thyroid is causing anything from cracked nails to a feeling of irritability.

From there, in addition to prescribing meds, your provider may direct you to make some helpful lifestyle changes. Some possibilities for DIY thyroid support include:

1. Supplements

“With most cases of general hypothyroidism, I recommend hitting a 30 milligram daily dose of zinc and a 200 microgram dose of selenium from food or supplementation,” says Neynaber. “Vitamin A may be necessary to get the thyroid hormone into the cells where it’s needed, as well.”

2. Diet changes

Folks with hyperthyroidism can benefit from limiting caffeine and foods with high iodine content (like seaweed and some seafood), while those with hypothyroidism might benefit from higher-iodine foods. Comite also encourages anyone with thyroid dysfunction to eat a balanced diet with plenty of anti-inflammatory, antioxidant-rich foods like fruits, veggies, and whole grains.

3. Exercise

Exercise helps increase sensitivity to circulating thyroid hormone (the vast majority of which is T4), Neynaber says. If your thyroid is acting up, be sure to keep up your workout routine.

4. Sleep

Though thyroid issues can make a good night’s sleep more elusive, healthy sleep hygiene can help put them to rest. A study from 2021, for example, found that low sleep quality could affect thyroid hormone levels, and that getting better rest was linked to more balanced levels.

5. Stress management

“Stress can worsen the proper conversion of thyroid hormone,” says Neynaber. Whenever possible, try incorporating calming practices like mindfulness, yoga, and deep breathing. Don’t underestimate the power of the mind-body connection to help your hormones do their best.

The Bottom Line

Both overactive and underactive thyroid can contribute to a variety of symptoms, some of which are more obvious than others. While many people associate changes in body temperature and weight loss or gain with thyroid issues, they may not realize that shifts in mood, brain fog, and even constipation can indicate that something’s not quite right with the body’s hormone HQ. Luckily, coordination with a healthcare professional and simple lifestyle changes can work wonders in promoting a healthy thyroid.