Home Diseases Underactive Thyroid (Hypothyroidism): Symptoms, Treatment, and Causes

Underactive Thyroid (Hypothyroidism): Symptoms, Treatment, and Causes

by Josephine Andrews
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Hypothyroidism (underactive thyroid)

Underactive thyroid (hypothyroidism) is what physicians call insufficient hormone production in the thyroid gland. The lack of hormones slows down all metabolic processes in the body and reduces performance. Hypothyroidism is one of the most common metabolic diseases. Women suffer from it more often than men. Here you can find everything you need to know about the symptoms, causes, and treatment of hypothyroidism.

ICD codes for this disease: E89 | E06 | E03 | E00

ICD codes are internationally valid codes for medical diagnoses. They can be found, for example, in doctor’s letters or on certificates of incapacity for work.

quick overview

  • Common symptoms: fatigue, weight gain, constipation, depression, cold
  • Investigations: blood test for thyroid values, ultrasound, scintigraphy
  • Treatment: L-thyroxine tablets
  • Caution: Check the hormone dose regularly (TSH value). Correct treatment is crucial during pregnancy
  • Specialist: internal medicine (endocrinology), gynecology (for pregnant women), general practitioner

Hypothyroidism: Symptoms

If the thyroid gland is underactive (hypothyroidism), the thyroid produces too little of the two hormones, thyroxine (T4) and triiodothyronine (T3). They influence almost all metabolic processes in humans and are therefore vital. While slight hypothyroidism usually hardly triggers symptoms, a stronger hormone deficiency significantly slows down nearly the entire metabolic activity. This sometimes causes severe discomfort.

General Symptoms

Common symptoms of hypothyroidism include poor performance, poor concentration, and fatigue. Affected people often feel weak and depressed.

Increased sensitivity to cold is also typical of hypothyroidism. The skin may be cool, dry, rough, and thickened; sometimes, yellowish discoloration occurs (storage of the dye carotene!).

In addition, an underactive thyroid can trigger hair loss and make the hair shaggy and lackluster. The muscles, in turn, tend to have cramps. Due to the slowed metabolism, those affected often gain weight without changing their eating habits.

Externally, an underactive thyroid can cause signs such as a swollen face with thickened lips and an enlarged tongue, swelling around the eye sockets, and thus slit-like narrowed eyelids.

The reason for the doughy, swollen skin is unique carbohydrate chains, so-called glycosaminoglycans. In hypothyroidism, they are no longer broken down properly and accumulate in the connective tissue. Doctors speak of so-called myxedema. The vocal cords may also be affected, resulting in a rough, hoarse voice.

An underactive thyroid can also cause the following symptoms:

  • Depressive mood
  • constipation
  • Slow heartbeat (bradycardia), enlargement of the heart, low blood pressure
  • Circulatory disorders with abnormal sensations (such as “pins and needles”)
  • Menstrual cycle disorders in women
  • Limitations of sexual desire (libido), fertility, and potency (erectile dysfunction = impotence)
  • goiter

Sometimes an underactive thyroid changes blood parameters such as the amount of hemoglobin and red blood cells. While these parameters may decrease hypothyroidism, cholesterol levels are often elevated. This can lead to premature hardening of the arteries (arteriosclerosis).

Hashimoto’s thyroiditis – i.e., chronic inflammation of the thyroid gland – can not only cause hypothyroidism but can also be accompanied by atrophy of the gastric mucosa (chronic atrophic gastritis) and other autoimmune diseases.

Symptoms in the elderly

In older people, sensitivity to cold, poor performance, or depression is often the only symptoms observed with hypothyroidism. It is not uncommon for such signs to be misinterpreted as signs of aging, dementia, or depression, and the actual cause – hypothyroidism – remains undetected.

Symptoms in babies

Babies with congenital hypothyroidism show typical symptoms immediately after birth: they move little, do not want to drink, and have weak muscle reflexes. Constipation and prolonged neonatal jaundice can also indicate an underactive thyroid.

If the hormone deficiency remains untreated, growth retardation, delayed mental development, and language development disorders occur as the disease progresses. This severe form of untreated hypothyroidism is called cretinism.

Hypothyroidism – 10 facts

Hormone production out of balance

The thyroid is a small organ with a significant effect: in particular, the hormones triiodothyronine (T3) and thyroxine (T4) influence many bodily functions – such as heartbeat, metabolism, heat production, and blood pressure. The effects are correspondingly large when the thyroid gets out of balance. Here you can read how to recognize an underactive thyroid and what to do.

Hypothyroidism – fat and listless

If the thyroid gland is underactive, insufficient thyroid hormones are circulating in the blood. Then the body’s basal metabolic rate decreases – those affected gain weight. Chronic constipation, excessive freezing, and fatigue are also common. Hypofunction can impair memory and thinking skills. The desire for sex dwindles, and men develop erectile dysfunction. In addition, people with hypothyroidism often have unkempt hair and doughy-looking skin.

Dangerous for children

Thyroid hormones are essential for body growth and brain maturation. This is why an underactive thyroid gland in childhood is particularly dangerous. Short stature and severe mental development disorders can be the result. Equally important is an adequate supply of thyroid hormones during pregnancy. Women who produce too little hormones have to help with hormone tablets.

When the immune system attacks the thyroid

Some people are born with an underactive thyroid. In most cases, however, it is the result of chronic inflammation triggered by an autoimmune disease, in particular, what is known as Hashimoto’s thyroiditis. The immune system attacks the thyroid tissue.

knots in the throat

Iodine deficiency can also cause an underactive thyroid because the body needs the trace element to produce the thyroid hormones. The thyroid can no longer produce enough hormones if it gets too little iodine. She tries to make up for this deficit by enlarging. Knots form or a so-called goiter (goiter) develops, which can take on tennis ball-sized dimensions. Such goiters used to be common, especially in areas lacking iodine in the soil.

One in four adults

For a long time, a goiter cannot be seen from the outside and is not noticeable in any other way. It is only later that symptoms such as difficulty swallowing appear, you get hoarse, or your shirt collar is too tight. Experts estimate that every fourth adult in Germany lumps the thyroid gland or goiter. However, only about one percent of the population suffers from a real hypofunction.

Fish protects the thyroid.

Because to prevent goiter from forming, people must take in enough iodine through food. An adult needs around 200 micrograms a day. Fish and seafood, in particular, contain a lot of iodine. Table salt enriched with iodine is now also widely available. Strongly visible goiters due to iodine deficiency only rarely occur.

Do I have an underactive thyroid?

If you suspect an underactive thyroid, the doctor will first ask about typical symptoms and examine you physically, including feeling your neck. A blood test is also essential. Certain hormone levels in the blood provide information about the function of the thyroid gland. Furthermore, an ultrasound examination and the detection of antibodies can be helpful.

Effective Medicines

An underactive thyroid can be treated well with medication. However, it sometimes takes a while for the values ​​to be set optimally. If an enlarged thyroid interferes with speaking, swallowing, or if it affects the blood supply, it can be reduced in size surgically or with the help of radiation.

Unfulfilled desire to have children – suspected thyroid

Women who do not become pregnant should have their thyroid checked. An imbalance in thyroid hormones can affect egg maturation and the menstrual cycle. This, in turn, can lead to infertility. The good news: women with an underactive thyroid can also become pregnant with hormone tablets.

Latent hypothyroidism: symptoms

In latent (“hidden”) hypothyroidism, the concentration of thyroid hormones is not (yet) reduced. Only the TSH value is increased. Therefore, symptoms such as poor performance and concentration, tiredness, etc., do not occur here or only to a minor extent.

Hypothyroidism: Causes and risk factors

Superordinate centers in the brain. The hypothalamus and pituitary gland (pituitary gland). Control the production of thyroid hormones: The hypothalamus releases the hormone TRH. It stimulates the pituitary gland to release the hormone TSH. This, in turn, promotes the production of thyroid hormones.

Production of thyroid hormones

production of thyroid hormones

Centers in the brain (hypothalamus and pituitary gland) are responsible for controlling the production of thyroid hormones. When the hypothalamus releases the hormone TRH, it stimulates the pituitary gland to release the hormone TSH. TSH, in turn, triggers the production of thyroid hormones.

The causes of an underactive thyroid gland can arise on three levels: disturbances in the function of the thyroid itself, disturbed TSH production in the pituitary gland, or insufficient TRH secretion from the hypothalamus. Doctors accordingly distinguish between different forms of hypothyroidism:

Primary hypothyroidism

By far, the most common cause of hypothyroidism lies in the thyroid itself. Doctors then speak of primary hypothyroidism. The causes can be congenital or only appear in the course of life:

Congenital hypothyroidism

Some children are born without a thyroid (athyroidism). In others, the thyroid gland is malformed (thyroid dysplasia), or there are errors in producing thyroid hormones. Even if a pregnant woman receives too high a dose of therapy for an overactive thyroid gland, the unborn child can develop an underactive thyroid gland.

Acquired hypothyroidism

Acquired hypothyroidism is, in most cases, the result of chronic inflammation of the thyroid gland. This so-called Hashimoto’s thyroiditis is an autoimmune disease: the body produces particular antibodies that destroy its thyroid tissue. It can then no longer produce a sufficient amount of thyroid hormones. It is still unclear why the body forms the antibodies.

Acquired hypothyroidism can also be the result of previous medical treatment. Therapy for an overactive thyroid gland (hyperthyroidism) sometimes overshoots the target. Radiation with radioactive iodine and treatment with medication for hyperthyroidism can disrupt hormone production so lastingly that over-functioning turns into under-functioning.

Thyroid surgery (e.g., due to an enlarged thyroid = goiter, goiter) can also lead to hypothyroidism if there is not enough healthy thyroid tissue left.

Iodine deficiency sometimes plays a role in the development of acquired hypothyroidism: the thyroid gland needs the trace element to produce thyroid hormones. If you don’t get enough iodine in your diet, you can develop extreme iodine deficiency, resulting in hypothyroidism.

Hypothyroidism – No special diet is necessary

Three questions:

  • How do I recognize an underactive thyroid?

The signs of an underactive thyroid, such as tiredness, severe concentration problems, weight gain, constipation, slow pulse, and a tendency to freeze, are rather unspecific. However, if two or three of these symptoms occur simultaneously over at least two weeks, you should see a doctor.

  • When is the helpful treatment?

If the TSH value is over 10, there is hypofunction. If, on the other hand, the TSH value is only slightly elevated, i.e., between 4 and 10, and the patient only has mild symptoms, a follow-up check in one to two months makes sense. Treatment should start only when the value is confirmed, and symptoms are present.

  • Do you have to pay attention to the diet if you have hypofunction?

The iodine content in normal nutrition is so low that there is no need to fear any effects. Even Hashimoto’s patients can use iodized table salt, go to the sea and eat sea fish. It would be best if you only avoided algae with a very high iodine content, as this can worsen the disease.

Secondary hypothyroidism

Hypothyroidism is caused by secondary hypothyroidism in the pituitary gland (pituitary gland): it produces too little TSH, which stimulates the thyroid gland to produce hormones. Doctors speak of pituitary insufficiency. In contrast to primary hypothyroidism, in the secondary form, both the T3/T4 blood values ​​and the TSH value are increased.

The disturbed TSH release can be a tumor in the pituitary gland or its surgical removal or radiation. A traumatic brain injury can also damage the pituitary gland. Secondary hypothyroidism is rare.

Tertiary hypothyroidism

Even rarer is tertiary hypothyroidism, the cause of which lies in the hypothalamus. It then produces too little of the hormone TRH, which ultimately regulates thyroid hormone production via the pituitary gland.

Hypothyroidism – frequency

About one percent of the population suffers from an underactive thyroid. About one in 3,200 newborns are born with hypothyroidism. This is called primary congenital hypothyroidism.

In addition to these patients with manifest hypothyroidism, numerous people have what is known as latent hypothyroidism: their blood levels of thyroid hormones are normal, but their TSH is elevated. This means that the thyroid gland only produces sufficient amounts of hormones when strongly stimulated by the pituitary gland. Latent hypothyroidism can later develop into manifest hypothyroidism.

Hypothyroidism: investigations and diagnosis

If hypothyroidism is suspected, the doctor will first ask about the typical symptoms and physically examine you. For example, he can feel the texture of your skin or the front neck region, where the thyroid gland is located. In this way, he can judge their size and consistency.

Laboratory values ​​of thyroid hormones

A blood test is also essential. The TSH value is one of the most critical blood values ​​for clarifying suspected hypothyroidism. The concentration of this hormone in the blood reveals how much the thyroid must be stimulated to produce enough thyroid hormones. If the thyroid gland is underactive, the TSH concentration in the blood is usually increased.

If the TSH level is elevated, the doctor will also determine the T4 level in the blood. If this is normal, this indicates latent hypothyroidism. However, if the T4 value is low, it manifests as hypothyroidism. However, the doctor constantly evaluates the hormone values ​​individually because different average values ​​depend on the patient’s age and weight. If there are no physical symptoms, he usually measures again.

You can read more about the hormonal thyroid values ​​in the article Thyroid values.

Further diagnostics in hypothyroidism

Under certain circumstances, doctors arrange for further examinations to determine the reason for the hypothyroidism:

  • Ultrasound examination: The size and condition of the thyroid gland can be determined using an ultrasound examination.
  • Biopsy: Sometimes, the doctor will also take a tissue sample for analysis in the laboratory. In this way, he can find indications of a tumor or inflammation.
  • Scintigraphy: With scintigraphy, the doctor examines the thyroid function using radioactively labeled substances (radionuclides).
  • Antibody detection: The doctor can examine the patient’s blood for auto-antibodies. This is how he determines whether Hashimoto’s disease is the reason for the hormone imbalance.

Antibody detection is beneficial for patients with latent hypothyroidism. If they have Hashimoto’s disease, there is an increased risk that the latent infection will eventually develop into a manifest illness.

Ultrasound scan to diagnose hypothyroidism

Ultrasound scan to diagnose hypothyroidism

In an ultrasound examination, the doctor can determine the size and condition of the thyroid gland.

Newborns are tested for hypothyroidism as part of the statutory early detection examination (U2). To do this, the doctor takes one or two drops of blood from the heel a few days after the birth, drips it onto filter paper, and uses it to determine the TSH value.

Diagnosis of secondary and tertiary hypothyroidism

TSH and T4 levels are low in rare cases, indicating secondary hypothyroidism. The doctor then tests the blood for other hormones to determine if the pituitary gland is affected. He then does magnetic resonance imaging (MRI) of the skull. For example, he can detect a tumor in the pituitary gland. It is similar when tertiary hypothyroidism is in the room.

Hypothyroidism: Treatment

The lack of hormones in hypothyroidism can be compensated for with hormone tablets, which patients usually take throughout their lives. Doctors also speak of replacement or substitution therapy. If it is dosed correctly, the patients’ quality of life and life expectancy are not restricted.

The drug of choice for hypothyroidism therapy is L-thyroxine (levothyroxine): This synthetic hormone acts like the natural thyroid hormone thyroxine (T4) and is partially converted in the body into the thyroid hormone T3. It must be taken in the morning on an empty stomach.

Treatment with L-thyroxine is started with a low dose and then slowly increased to the final individual amount. If the dose is increased too quickly or you overdose, heart problems or other signs of an overactive thyroid may occur.

The final dose depends on the basal TSH value (it should normalize) and the patient’s subjective well-being. The doctor checks the TSH blood value at the earliest eight weeks after the start of therapy or a change in dose. Once the right dose has been reached, the check-up is usually only every six months and annually (often in infants).

If the symptoms do not improve despite treatment, the doctor will refer the patient to an endocrinologist, a specialist in human hormone balance.

By the way: In the case of secondary hypothyroidism, the patient usually has to take other hormone tablets that the pituitary gland no longer produces.

Hypothyroidism: treatment in the elderly

Older patients with an underactive thyroid need a smaller amount of L-thyroxine because the natural hormone levels in old age differ from those in younger years. Doctors start with a lower starting dose (half that for younger adults). However, he sets the final amount higher than for young people. Low TSH levels in people over 70 are associated with higher mortality.

Hypothyroidism: treatment of pregnant women

Hypothyroidism must be checked regularly during pregnancy because the body needs more thyroid hormones. Therefore expectant mothers with hypothyroidism get an increased dose of L-thyroxine; otherwise, there is a risk of a miscarriage or premature birth in the worst case. If the tablets are stopped prematurely, the unborn child can also suffer physical and mental damage because the child’s thyroid gland only begins to synthesize thyroxine from the 12th week of pregnancy.

Hypothyroidism: treatment of children

Children with congenital hypothyroidism must also take the missing thyroid hormone every day. The children usually develop mentally if the intake is started during the neonatal phase. However, permanent mental damage can be expected if congenital hypothyroidism is only recognized and treated at three to six months.

Treatment of latent hypothyroidism

The doctor decides individually whether latent hypothyroidism should be treated. Current guidelines do not recommend therapy if the patient has no symptoms and the TSH value is only slightly elevated. However, it is advisable to check the TSH value regularly. Patients with a significantly increased TSH value should take L-thyroxine (in low doses). This should reduce the risk of early hardening of the arteries and infertility.

Pregnant women with latent hypothyroidism should take hormone tablets, as normal TSH and T3/T4 values ​​are essential for the child’s development.

Apart from these recommendations, it depends on your wishes whether you have latent hypothyroidism treated. Let your doctor explain the pros and cons to you.

Hypothyroidism: Homeopathy

Especially with chronic diseases such as hypothyroidism, many patients hope for help outside of conventional medicine. But can an underactive thyroid be treated homeopathically? Homeopathy reaches its limits in the case of illnesses that require substitution therapy.

However, homeopathy can be used alongside conventional medical hypothyroidism therapy. For example, Graphites D12 is recommended for hypothyroidism with a slowed metabolism, overweight, and freezing despite standard room or the outside temperature. An experienced therapist can advise patients on which homeopathic remedies can also support the conventional medical treatment of hypothyroidism.


The concept of homeopathy and its specific effectiveness is controversial and not proven by studies.

Hypothyroidism: Prevention

The most common reason for an underactive thyroid is an autoimmune disease (Hashimoto’s thyroiditis). In this disease, the body’s immune system attacks its thyroid gland. This cause of hypothyroidism is usually unpreventable.

The situation is different with hypothyroidism caused by iodine deficiency. Make sure you eat a diet rich in iodine. Use iodized table salt and eat fish regularly. Many types of fish naturally contain large amounts of iodine. You can read more about iodine-rich nutrition in the article “Underactive thyroid function – nutrition.”

Diet tips

If you have an underactive thyroid, a few essential things to consider regarding your diet. Because the hormone tablets are not compatible with all foods, for example, calcium-rich foods block the absorption of L-thyroxine from the intestine and thus change the hormone level in the blood. Other foods or drinks can also interact with the drug.

If there is still residual thyroid function – and this is the case in many patients, at least for a specific time – you should ensure that you get enough iodine with your food. Sufficient iodine intake is also essential prevention of thyroid enlargement, the so-called iodine deficiency goiter.

How you can prevent an underactive thyroid gland with the proper diet, which foods are particularly rich in iodine, and what you should consider when treating hypothyroidism can be found in the article Underactive thyroid gland – nutrition.

Losing weight with hypothyroidism

People with an underactive thyroid often have a weight problems. This is because their metabolism is slower than healthy people’s due to the lack of thyroid hormones.

This reduces the so-called basal metabolic rate, i.e., the amount of energy that the body needs at rest to maintain bodily functions (e.g., body temperature, circulation, digestion). In addition, more water is stored in the tissue.

Nevertheless, it is possible to lose weight even with a thyroid function. The most important key to this is drug treatment with thyroid hormones. But the right balance of calorie intake and calorie expenditure is also important.

You can find out what you should pay particular attention to in the article Hypothyroidism – Losing weight.

Hypothyroidism: disease course and prognosis

Hypothyroidism can be effectively treated by taking hormone tablets (substituted hypothyroidism). This treatment usually has to be continued for life. Patients who follow the therapy exactly can then lead an utterly everyday life. They are not limited in their performance and life expectancy. Pregnancy is also quite possible for women with an underactive thyroid.

The situation is different in the case of years of untreated hypothyroidism. Consequences such as increased cholesterol levels, hardening of the arteries (arteriosclerosis), and infertility are not uncommon.

Complication: myxedema coma

The so-called myxedema coma can lead to severe complications if hypothyroidism remains untreated. It is extremely rare these days as hypothyroidism is usually treated. However, when it does occur, it is life-threatening.

Triggered by an infection, operation, or injury, patients experience hypothermia, lack of oxygen, and a drop in blood pressure. The skin on the face, arms, and legs swells up.

Patients with myxedema coma must be rushed to the intensive care unit immediately. They receive glucocorticosteroids (“cortisone”) and thyroid hormones directly into the vein.

Desire to have children with hypothyroidism

A disturbed thyroid gland function is a common reason for an unfulfilled desire to have children. About every tenth couple is childless for this reason. Because the hormones of the thyroid gland have a variety of effects on the metabolism and thus also on the gonads and sexual function, in women, a malfunctioning thyroid gland can disrupt egg maturation and the menstrual cycle, among other things.

There is no need for a fully developed hypothyroidism with a detectable hormone deficiency. Studies have shown that even latent hypothyroidism, in which only an elevated TSH value can be detected, makes it difficult to get pregnant.

You can find out what your doctor can examine in connection with the thyroid gland if you cannot get pregnant and what treatment options are available in the article Underactive thyroid – Desire to have children.

Prognosis in children with congenital hypothyroidism

If the doctor recognizes congenital hypothyroidism immediately after birth and treats it, the children will develop normally. Only short stature can be positively influenced if therapy is initiated too late. However, brain damage and intellectual developmental disabilities caused by an underactive thyroid remain.

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