23 Symptoms That Could Indicate Hyperthyroidism

When your thyroid goes into overdrive, your entire body feels the ripple effects. Hyperthyroidism—also known as an overactive thyroid—occurs when the thyroid gland produces excessive amounts of the hormones triiodothyronine (T3) and thyroxine (T4), which regulate your metabolism and energy use. This hormonal surge can throw off everything from your heartbeat to your mood and digestion. The most common culprit? Graves’ disease, an autoimmune condition that triggers the thyroid to pump out hormones nonstop. But there are other causes too—and the symptoms can be surprisingly diverse, often mistaken for stress, aging, or other health issues. That’s why we’ve expanded our list to 23 signs that could point to hyperthyroidism. From unexplained weight loss and rapid heartbeat to anxiety, sleep disturbances, and skin changes, these red flags are your body’s way of signaling that something’s off. Catching them early could make all the difference in managing your thyroid health.

1. Shifts In Appetite

Hyperthyroidism may cause either an increase or decrease in appetite or a complete change in the type of food a person craves. The majority of patients with hyperthyroidism will experience an increase in appetite, but any unprovoked change in taste might be a sign. Weight changes and an increase in thirst are also common symptoms of hyperthyroidism. Some individuals may gain weight and others will lose it. Keeping a daily food journal is a great way to track any appetite changes. Be sure to note any food cravings, what you ate, when you ate it, and how you felt afterward.

2. Mood Swings

Experiencing a rapid change in hormone levels can be unsettling. Abnormal thyroid hormone levels may cause changes in mood or behavior such as mood swings, nervousness, hyperactivity, irritability, or panic attacks. Medications are available to assist with mood changes; however, it should be noted that many medicines come with physiological side effects similar to the symptoms of the disease itself. For example, steroids can cause depression, anxiety, and mood swings. Work with your doctor to find a treatment option that includes diet, exercise, and medication if needed.

3. An Irregular Heartbeat

Overproduction of thyroid hormones affects the heart’s function in many ways. Hyperthyroidism may cause abnormal heart rhythm, the sensation of an irregular heartbeat, or a fast heart rate. Certain medications prescribed for thyroid function may also cause an irregular heartbeat or other undesirable side effects. Beta blockers are designed to slow down heart rate and reduce anxiety but may produce feelings of depression, fatigue, and the inability to concentrate in people with an overactive thyroid.

4. Lighter And Less Frequent Menstrual Periods

Having an irregular menstrual period might not seem ideal, but it’s an excellent way to predict how well a woman’s thyroid is functioning. Whereas an underactive thyroid may cause a heavier flow more often with more severe cramps, hyperthyroidism may cause shorter and lighter periods. Periods may also be farther apart due to high levels of thyroid hormones, which can make conceiving a bit trickier. Thyroid problems may also cause a decreased interest in sex.

5. Changes In Appearance

Hyperthyroidism is caused by an autoimmune condition known as Grave’s disease in which the thyroid gland overproduces hormones. Symptoms of the disease may include weight gain or loss, loss of hair, skin problems, and inflammation behind the eye. Due to the overproduction of hormones, the skin may become oily and develop acne easier than before. Grave’s disease may also cause excess sweating, bulging eyes, vision problems such as double vision, heat intolerance, and a goiter.

6. Bowel Dysfunction

Whereas hypothyroidism may cause constipation, hyperthyroidism can cause more frequent bowel movements or diarrhea. The thyroid plays a significant role in metabolism and digestion because of its ability to release hormones that influence how your body handles nutrients. Overproduction of hormones creates an overactive digestive system that eliminates frequently and may also cause stomach pain and sensitivity to many foods. For example, people with Grave’s disease are five times more likely to develop Celiac disease. A good place to start is to eliminate gluten, dairy, and processed foods from the diet.

7. A Close Family Member Has Similar Issues

Hyperthyroidism can run in some families, therefore, if you have a close relative with this condition, you may want to get your thyroid checked. Hyperthyroidism is also connected to the autoimmune conditions Hashimoto’s disease, Crohn’s disease, Celiac, and Grave’s disease. If you or one of your close family members has one of these autoimmune conditions, you may be at an increased risk. Blood work can be done to determine whether you have the antibodies for Grave’s disease, which is a reliable indicator of an overactive thyroid.

8. Symptoms Suddenly Appear With New Medication

Certain medications, including aluminum-containing antacids, Didanosine (an HIV antiviral drug), and Sucralfate (an antacid), as well as resin binders, calcium carbonate, iron, and sodium polystyrene sulfonate, have been shown to inhibit the absorption of thyroid hormones and decrease their efficiency. If your symptoms began after you started taking a particular medication or supplement, discontinue use and talk to your doctor about possible problems.

9. Sleep Difficulties

Sleep-related disorders and issues can arise when an individual has an overactive thyroid. Symptoms include insomnia, frequent waking throughout the night, restlessness, snoring, anxiety (due to lack of sleep), heart palpitations, restless leg syndrome, and tremors, which can all disrupt sleep. While some patients may feel energetic throughout the day with no signs of any sleep difficulties or chronic fatigue, many do experience fatigue and exhaustion, while also feeling anxious and restless. Many patients go to bed feeling exhausted but then have a hard time falling asleep and remaining asleep throughout the night, and may not wake up feeling refreshed as most individuals normally do. Some hyperthyroid patients may develop sleeping disorders such as sleep apnea, night sweats, and insomnia, due to their lack of sleep, and in particular, night sweats are a common problem for many hyperthyroid patients as their body has difficulty regulating its temperature throughout the night.

10. Increased Sweating & Heat Intolerance

As we know, hyperthyroidism occurs when the thyroid produces too much thyroxine, a naturally occurring hormone within the body that affects the regulation of the body’s metabolism. When there is an increase in thyroxine, it causes the body’s metabolism to increase, leading to a rising body temperature that can be tricky to regulate. Heat intolerance, perspiration, flushing, and excessive sweating are all symptoms that can occur due to the increase in this hormone. When functioning correctly, the thyroid is able to properly respond to changes in temperature by adjusting the body’s basal metabolic rate (BMR) and releasing hormones to promote cellular release (aka sweating) or retention of heat, allowing the body to remain at a comfortable temperature. With hyperthyroidism, the body cannot regulate these hormones as easily, therefore, many patients have difficulty adjusting to the heat, causing them to become heat intolerant. As a result of them 'overheating,' many patients will begin to excessively sweat.

11. Excessive Fatigue

Fatigue, similar to sleep difficulties, is another symptom of hyperthyroidism, generally resulting from insomnia, anxiety, sleep apnea, night sweats, and disrupted sleep patterns. Similar to hypothyroidism, if Graves’ disease is the underlying cause for an individual’s thyroid issues, treating Graves’ disease and hyperthyroidism will typically resolve excessive fatigue. Sleep apnea, another serious sleeping disorder, can also greatly contribute to fatigue due to reduced oxygen intake while sleeping. Besides fatigue and lingering grogginess, sleep apnea can also cause a patient to snore, wake up gasping for air, headaches, and waking up at night to urinate. There are some ways a patient with hyperthyroidism who are experiencing fatigue can try to optimize their sleep health to reduce the amount of fatigue they feel the next day. For instance, they can try to keep their bedroom cooler, avoid electronics before bedtime, minimize light in the bedroom, avoid caffeine and alcohol in the afternoon, avoid naps, and avoid exercising after dinner.

12. Tremors

It may start as just a fine trembling in the hands and fingers, but don’t be fooled as hyperthyroidism can cause tremors to occur in most patients. To put it into perspective why tremors occur, let’s break down the thyroid gland. Located in the neck, just above the collarbone, the thyroid gland regulates the body’s metabolism, and when it is in overdrive, the whole body speeds up, causing tremors to develop. This is due to an increase in energy production by every cell in the body, resulting in nervous stimuli to become excessive, such as a hand tremor. The shaking can be barely noticeable or exaggerated, as the level of intensity depends on the excitability of the nerves, as well as how much the thyroid hormone has increased. A tremor is generally more common in women than in men, as hyperthyroidism affects more females than males. The following risks can also contribute to a tremor developing on top of hyperthyroidism, such as a family history of the disease, Type I diabetes, pernicious anemia, primary adrenal insufficiency, excessive iodine consumption, over the age of sixty, and if a woman has been pregnant in the last six months.

13. Shortness Of Breath

Similar to other conditions, hyperthyroidism can cause shortness of breath to develop, as this condition causes the respiratory muscles to weaken and decrease in pulmonary function. Specifically, hyperthyroidism increases respiratory drive and can cause dyspnea on exertion, or shortness of breath. A patient may notice this sign whenever they become winded just from walking to the mailbox or climbing a flight of stairs, but many patients notice it is especially when they are at rest or during exercise. Specifically, the trachea becomes compressed, which can be positional, and can happen with nodular goiters (lumps on the neck) and thyroid cancer, but is also commonly seen in patients with hyperthyroidism, as the lungs do not respond properly to the increased metabolic rate caused by this condition.

14. Muscle Weakness, Especially in the Upper Arms and Thighs

Many people associate muscle fatigue with overexertion, but hyperthyroidism can quietly weaken large muscle groups over time—especially in the shoulders, upper arms, and thighs. Tasks like climbing stairs, lifting groceries, or even blow-drying your hair can suddenly feel unusually difficult. This is because the accelerated metabolism breaks down muscle tissue faster than the body can rebuild it. If you're losing muscle tone despite staying active, or feel unexpectedly shaky during everyday movements, your thyroid could be the hidden culprit.

15. Brittle Nails and Thinning Hair

If your nails are peeling or breaking more easily—or your hairbrush seems fuller than usual—it could be more than just a change in the weather. Hyperthyroidism affects the body’s ability to absorb nutrients like biotin and iron, which are essential for strong nails and healthy hair. Over time, you may notice hair becoming fine, limp, or thinning around the crown and temples. Brittle nails that crack, split, or form ridges may also emerge. This seemingly superficial change is actually a key outward sign of inner hormonal chaos.

16. Voice Changes or a Hoarse Throat

As the thyroid gland enlarges (goiter), it can start to press against nearby structures in the neck—including the voice box. This may cause subtle voice changes, hoarseness, or even a feeling like you constantly have to clear your throat. Some patients describe it as a "tightness" or “tickle” in the throat, even in the absence of a cold. If your voice sounds different or you find yourself frequently hoarse, your thyroid could be playing a bigger role than you realize.

17. Increased Frequency of Urination

Hyperthyroidism can speed up every system in the body—including the kidneys. This can lead to more frequent urination, especially at night. While it’s easy to blame this symptom on hydration or aging, increased urine output (sometimes coupled with a heightened thirst) may signal a hormonal imbalance. In more severe cases, this can contribute to dehydration, fatigue, and electrolyte imbalances—especially if you're also sweating excessively.

18. Skin That Feels Warm and Moist

An overactive thyroid pumps up the body’s metabolic engine, raising internal temperature and increasing blood flow to the skin. This often results in warm, moist skin—even in cool environments. Some patients describe their skin as constantly “clammy” or flushed, especially on the palms of the hands or soles of the feet. This symptom may be accompanied by increased sensitivity to fabrics or skin irritation due to frequent sweating.

19. Difficulty Concentrating (a.k.a. “Thyroid Fog”)

Brain fog isn’t exclusive to hypothyroidism. Hyperthyroidism can also interfere with cognitive clarity, making it hard to focus, remember details, or complete tasks. Some describe it as “mental hyperactivity” where thoughts are racing, but memory and decision-making suffer. This can be especially frustrating for high-performing individuals who suddenly feel scattered, forgetful, or overwhelmed by routine tasks.

20. Increased Anxiety or Panic Attacks

While anxiety can have many root causes, hyperthyroidism is a physiological trigger that’s often overlooked. Excess thyroid hormone overstimulates the nervous system, leading to restlessness, jitteriness, and even full-blown panic attacks—sometimes with no obvious emotional cause. If you’re experiencing heart palpitations, a sense of dread, or difficulty relaxing despite no clear trigger, it’s worth checking your thyroid levels.

21. Irregular Body Temperature Fluctuations

Feeling hot one moment and chilled the next? Hyperthyroidism can cause erratic shifts in body temperature, not just heat intolerance. These fluctuations are often a result of the body’s inability to stabilize its internal thermostat. You might bundle up under a blanket only to toss it off moments later. This cycle is not just annoying—it’s a subtle but telling sign that your thyroid is affecting your thermoregulation system.

22. Heightened Sense of Smell or Taste

While some people lose their sense of smell or taste due to illness or aging, others with hyperthyroidism report sudden hypersensitivity to smells or flavors. Everyday odors may seem overpowering, and food may taste more intense—or even off-putting. These sensory changes are thought to be linked to the overstimulation of the central nervous system and are worth noting, especially if paired with other thyroid symptoms.

23. Neck Fullness or Pressure

Even if you don’t see a goiter, hyperthyroidism can cause a sense of tightness or fullness in the neck. This might feel like difficulty swallowing, a lump in the throat, or a persistent urge to adjust your collar. In some cases, this discomfort is caused by subtle thyroid swelling or nodules that aren’t yet visible but are exerting pressure on surrounding tissues. If you experience unexplained tightness or discomfort in the neck, ask your doctor about a thyroid ultrasound.

When Symptoms Point to Hyperthyroidism

Hyperthyroidism often hides in plain sight, masquerading as everyday annoyances—fatigue, mood swings, weight changes, or even a little extra sweat. But when these symptoms stack up, they may be your body’s way of sounding the alarm. With an overactive thyroid, your metabolism, heart, muscles, skin, and mind are all pushed into overdrive, often leading to confusing and disruptive symptoms. That’s why recognizing the early warning signs is so important. By expanding our list to 23 key indicators, we hope to shed light on just how far-reaching hyperthyroidism can be. Whether it's unexplained anxiety, changes in your menstrual cycle, tremors, or sudden sensitivity to heat, your body is trying to tell you something. If any of these symptoms resonate, don’t ignore them—speak with a healthcare provider and request a simple blood test to check your thyroid function. Catching it early can make all the difference in restoring balance and protecting your long-term health.