Underactive thyroid (hypothyroidism) - causes, symptoms and natural help

Apr 27, 2025

The thyroid gland is located in the front of the neck below the larynx and is butterfly-shaped. It plays a central role in controlling many bodily processes - especially energy and hormone balance. Its main task is to produce the hormones T3 (triiodothyronine) and T4 (thyroxine), which regulate the metabolism, influence body temperature, accelerate the heartbeat, promote digestion and activate the nervous system [1]. For this to work, the thyroid gland needs sufficient iodine - a vital trace element that must be taken in with food. If there is an iodine deficiency, the thyroid gland can no longer produce enough hormones, resulting in hypothyroidism.

What is hypothyroidism?

In the case of hypothyroidism, the thyroid gland produces too few hormones on a permanent basis. The thyroid gland is a butterfly-shaped organ at the front of the neck below the larynx. Its hormones T3 (triiodothyronine) and T4 (thyroxine) control the metabolism and numerous bodily functions [1]. If there is too little thyroid hormone in the blood, the body reduces its energy consumption: those affected often feel tired, freeze easily, gain weight and notice other symptoms (see below). This is often referred to as "hypothyroidism". The medical term hypothyroidism literally means "underactive thyroid metabolism".

The thyroid gland itself is regulated by the hormone system: The pituitary gland (hypophysis) constantly measures the hormone level in the blood and releases TSH (thyroid-stimulating hormone) as required. TSH stimulates the thyroid gland to produce more T4 and T3. In the case of hypothyroidism, the TSH value usually rises because the pituitary gland tries to stimulate the sluggish thyroid gland more strongly. Conversely, the direct thyroid hormones T3 and T4 are lower in the blood. A significantly elevated TSH value (> 4 mU/L) and low T4 levels are therefore considered a laboratory indication of hypothyroidism [2]. Doctors determine these thyroid levels in the blood to confirm the diagnosis.

You can read more about this in the section Diagnosis: Understanding thyroid levels.

Causes: Why does hypothyroidism develop?

There are various causes of hypothyroidism. The most common trigger is an autoimmune disease: Hashimoto's thyroiditis (chronic inflammation of the thyroid gland) causes the immune system to attack and destroy healthy thyroid tissue. As a result, the thyroid gland can no longer produce enough hormones. In fact, Hashimoto's disease is the most common cause of hypothyroidism today [1]. Women are affected more frequently than men, and Hashimoto's often runs in families or occurs together with other autoimmune diseases (e.g. type 1 diabetes or coeliac disease).

In addition to autoimmune diseases, there are other triggers:

Iodine deficiency: iodine is an essential building block of thyroid hormones [3]. Long-term iodine deficiency can enlarge the thyroid gland (goitre formation) and lead to hypothyroidism. Around 800 million people worldwide suffer from iodine deficiency and the resulting health problems (goitre, hypothyroidism, mental developmental disorders, etc.) [3]. In Germany, the use of iodized table salt has significantly improved the iodine supply, but certain groups (e.g. strictly vegan diets without seafood) may still have insufficient iodine intake.
Excess iodine: Interestingly, too much iodine can also trigger or exacerbate hypothyroidism in sensitive individuals or those with existing thyroid disease [1]. This phenomenon (Wolff-Chaikoff effect) occurs, for example, after very high doses of iodine. Food supplements with high doses of iodine (e.g. algae supplements) should therefore be used with caution - more on this later.
Thyroid operations and therapies: If all or part of the thyroid gland has been surgically removed (e.g. due to lumps or cancer) or irradiated by radioiodine therapy, thyroid tissue is subsequently missing. The result is almost always hypothyroidism [1], which must be compensated for by hormone administration.
Medication and toxins: Certain medications can cause hypothyroidism as a side effect. A well-known example is lithium, which is used in psychiatry [1]. High doses of iodine-containing medications (e.g. amiodarone, a heart medication) or X-ray contrast agents as well as some immunotherapeutic agents can also reduce thyroid function. Environmental factors such as high exposure to heavy metals could also play a role. In naturopathy, it is also discussed whether certain foods with so-called goitrogenic substances (e.g. unprocessed soy, cabbage) can inhibit iodine uptake in very large quantities - however, this is rarely relevant in a normal diet.
Inflammation (thyroiditis): Apart from the autoimmune form Hashimoto's, thyroid inflammation can also be caused by viruses, bacteria or after pregnancy. Acute inflammation often initially leads to the release of too much hormone (excess phase) and subsequently to temporary hypothyroidism [1]. This form can normalize again after a few months, but requires careful medical monitoring.
Congenital disorders: In rare cases, the thyroid gland is already underdeveloped at birth or there is a congenital hormone metabolism defect. Newborns are therefore routinely tested for hypothyroidism (neonatal screening), as there is a risk of serious consequences for growth and brain development if left untreated [1].
Central hypothyroidism: Very rarely, the cause is not in the thyroid gland itself, but in its control by the brain (pituitary/hypothalamus). If the pituitary gland no longer produces TSH, e.g. due to a tumor, the otherwise healthy thyroid gland remains underactive (secondary or central hypothyroidism) [1]. This form requires special diagnostics, as the TSH value in the blood is not elevated here, but is conspicuously low.

Overall, Hashimoto's is the most common cause in this country, followed by therapeutically induced hypothyroidism (surgery/radioiodine) and iodine deficiency. The doctor clarifies the exact cause based on the patient's medical history, blood values (e.g. detection of anti-thyroid antibodies in Hashimoto's) and, if necessary, an ultrasound examination of the thyroid gland.

Symptoms of an underactive thyroid

The onset of hypothyroidism often causes unspecific symptoms. The symptoms develop gradually over months or years [4]. Many sufferers hardly notice anything at first. Typical symptoms of hypothyroidism are

Chronic tiredness and exhaustion: persistent tiredness, listlessness and an increased need for sleep are among the most common signs. Performance is reduced and many people feel mentally and physically "slowed down".
Increased sensitivity to cold: hypofunction patients freeze easily, are often cold ("shivering even in summer") and tend to have a low body temperature. The reduced metabolic activity means that less heat is generated in the body [5].
Weight gain: Despite unchanged eating habits, many sufferers gain weight. This is due to a slower metabolism and water retention (myxedema). However, a moderate increase (a few kilos) is typical; severe obesity usually only occurs in cases of pronounced and prolonged hypofunction.
Depressive mood: An untreated hypothyroidism can affect your mood. Those affected report feeling down, a loss of interest and, in extreme cases, even depression [6]. Anxiety can also increase. These psychological symptoms often improve as soon as hormone replacement therapy takes effect [7].
Concentration problems and "brain fog": Many people complain of memory problems, slowed thinking or difficulty concentrating. In studies, 36% of hypothyroidism patients reported slower thinking and 39% noticed a deterioration in memory [8].
Changes to skin, hair and nails: The skin is often dry, cool and pale. Many notice a rough, scaly skin surface; sometimes there is itching (e.g. on the scalp) due to the dryness. Hair loss is a common symptom: the hair becomes thinner, more brittle and falls out more frequently [9]. The eyebrows can also thin out - classically, the outer third of the eyebrows is lost if hypofunction persists for a long time [10]. Fingernails grow more slowly and can become brittle. The cause of all these changes is that skin cells and hair follicles stop regenerating quickly without sufficient thyroid hormone: The skin renews more slowly, becoming dry and flaky as a result, and hair remains in the resting phase (telogen phase) for longer [11]. This results in dry patches of skin and increased hair loss, which often occurs diffusely all over the head.
Muscle weakness and joint pain: Low thyroid hormone levels also slow down muscle protein synthesis and promote muscle breakdown [12]. Many of those affected feel physically weaker, have difficulty lifting heavy objects or being active for long periods of time. Muscle cramps and joint problems are also more common. Around a third of people with hypothyroidism report muscle cramps without unusual physical exertion [13].
Slowed cardiovascular function: The pulse is often slow (bradycardia), and blood pressure may be low. Some sufferers develop high cholesterol levels because fat metabolism is reduced. If left untreated, pronounced hypofunction increases the long-term risk of cardiovascular problems (e.g. heart failure or arteriosclerosis).
Digestive problems: Due to the slower metabolism, digestion also works more slowly. Constipation is a frequent consequence. Some patients suffer from persistent constipation despite a high-fiber diet. More rarely, nausea or loss of appetite may also occur. (Diarrhea, on the other hand, is more a sign of hyperfunction).
Other possible signs: Women sometimes notice cycle disorders (e.g. irregular or very heavy menstrual bleeding) and fertility problems. Men may develop erectile dysfunction. Blood cholesterol levels are often elevated. In severe cases, there is a pasty swelling of the skin (myxedema), particularly on the face, eyelids and lower legs. If left untreated, severe hypothyroidism can in rare cases progress to life-threatening myxedema coma.

Hair loss and itchy scalp due to the thyroid gland

One of the most visible symptoms of hypothyroidism is hair loss. Many sufferers notice that their hair becomes thinner or falls out in clumps, often accompanied by a dry, itchy scalp. The reason: hair follicles are very sensitive to thyroid hormones. If these are missing, the hair growth cycle is disrupted - new hair grows back more slowly and old hair falls out more frequently [5]. The scalp also produces less sebum, which can lead to dryness and dandruff. Dandruff irritation and dry skin then cause the typical itchy scalp.

The good news is that if the hypothyroidism is treated and the hormone levels are normalized, the hair loss usually stops. The hair follicles regenerate, but it takes patience - often several months - for the hair to grow back fully. In the meantime, mild shampoos for dry, itchy scalps, scalp massages (to promote blood circulation) and a diet rich in biotin and nutrients can support the health of the hair roots. The actual treatment of the thyroid gland is particularly important, as otherwise all external applications will only have a limited effect.

Diagnosis: Understanding thyroid values

Hypothyroidism is often suspected from the symptoms alone. To confirm this, thyroid levels are determined in the blood. The focus here is on TSH (thyroid-stimulating hormone). TSH acts as a signal transmitter from the pituitary gland to the thyroid gland: if the T3/T4 hormone level is too low, TSH rises to stimulate the thyroid gland [7]. Therefore, an elevated TSH level is the most sensitive indication of hypothyroidism. In most laboratories, the normal range for TSH is around 0.4 - 4.0 mIU/L [2]. Values above this indicate hypothyroidism (the higher the value, the more underactive the thyroid gland), while very low TSH values indicate hyperthyroidism [2].

However, the direct thyroid hormones must also be taken into account:

Free T4 (fT4): Thyroxine is the main product of the thyroid gland. In the case of hypothyroidism, fT4 is usually low because the diseased thyroid gland cannot produce enough T4. Normal values are around 10-23 pmol/L (0.8-1.8 ng/dl), depending on the laboratory. Important: In mild or incipient cases, fT4 may still be within the normal range, while TSH is already elevated - this is called subclinical hypothyroidism.
Free T3 (fT3): Triiodothyronine is the biologically more active thyroid hormone, which is largely converted from T4 in the body tissues. In many cases, fT3 remains normal for longer in the case of hypothyroidism and only falls in later stages. Therefore, fT3 is less sensitive for diagnosis. However, low fT3 is seen in severe cases.
Antibodies: Antibodies against thyroid components are often determined to find the cause. In Hashimoto's, TPO antibodies (against the enzyme thyroid peroxidase) and/or Tg antibodies (against thyroglobulin) are found in over 90% of cases. High antibody titres confirm the autoimmune cause, even if the hypofunction may initially be mild.
Other values: In routine practice, accompanying abnormalities may occur, such as elevated cholesterol levels (LDL) or mild anemia, which can be attributed to the slowed metabolism [14]. These usually normalize again after successful therapy.

To confirm the diagnosis, an ultrasound of the thyroid gland is often also performed. This allows the size and tissue structure of the thyroid gland to be assessed. Typical of Hashimoto's thyroiditis is a low-echo, inhomogeneous glandular image with a frequently reduced thyroid gland size over the course of the disease. Nodules or other changes can also be detected. In unclear cases, further tests are available (e.g. TRH stimulation test for suspected central hypothyroidism, scintigraphy for functional assessment of nodules, etc.). As a rule, however, TSH, fT4/fT3 and antibody determination are sufficient to make a clear diagnosis of hypothyroidism.

Treatment: synthesis or natural thyroid hormones?

The standard treatment for hypothyroidism is the administration of synthetic thyroid hormones. Levothyroxine (T4) is primarily prescribed in tablet form to compensate for the hormone deficiency. If taken in the correct dosage, a normal metabolic state can be achieved. T4 tablets are only available on prescription and usually have to be taken for life (e.g. in the case of Hashimoto's or after thyroid surgery). The dosage is adjusted individually based on the blood values (TSH target range usually in the upper normal range).

Some patients ask for natural thyroid hormones as an alternative. This usually refers to animal thyroid extracts, for example from pig thyroid glands, which are dried and offered in tablet form (so-called "Natural Desiccated Thyroid", NDT). Such preparations contain a mixture of T4 and T3 in a natural ratio. However, they are not freely available in Germany - it is not possible to obtain natural thyroid hormones over the counter in this country. NDT preparations are subject to prescription and are only prescribed by doctors in exceptional cases, e.g. if no sufficient improvement is achieved with a pure T4 preparation. Studies show that NDT is comparable to levothyroxine in terms of objective effect [15]. In one study, around half of the patients preferred the dried thyroid extract to pure T4, while just under 19% preferred levothyroxine - the remainder noticed no difference [15]. Some reported slightly better well-being and easier weight loss with NDT [15]. However, the data is limited and endocrinologists warn against dosage fluctuations with non-standardized "glandular preparations".

The fact is that manifest hypothyroidism should not be left untreated. Non-prescription approaches (diet, micronutrients, home remedies) can support conventional therapy, but cannot replace thyroid hormone replacement if there is a significant hormone deficiency. Therefore, always discuss with your doctor which therapy is suitable for you. In some cases (e.g. mild, subclinical hypothyroidism without symptoms), you can initially be observed or counteracted with diet and micronutrients. In most cases, however, hormone replacement therapy will be necessary sooner or later in order to avoid consequential damage. Natural thyroid hormones from animal sources are a possible option, but in Germany they are only available on prescription and under medical supervision - NDT "thyroid buy" is therefore not allowed without further ado.

Lifestyle and home remedies: make your thyroid strong

Lifestyle measures can help to keep the body in balance despite hypothyroidism and relieve the thyroid gland - true to the motto: "Make your thyroid strong". The following approaches from lifestyle, naturopathy and home remedies can have a supportive effect:

Reduce stress: Chronic stress can affect the hormonal axis and promote inflammation. Allow yourself sufficient rest and sleep. Relaxation techniques such as yoga, meditation or autogenic training can reduce stress levels. In the case of Hashimoto's, it is suspected that stress can have a negative impact on the immune system - so reducing stress is good in more ways than one.
Sleep and rest: Make sure you get enough sleep (7-8 hours per night). If you are tired due to hypofunction, your body is exhausted anyway - so allow yourself to catch up on sleep. A regular sleep-wake cycle supports the hormone balance.
Moderate exercise: Regular exercise can boost the often slowed metabolism, lift your mood and help against weight gain. Moderate endurance-oriented activities (walking, cycling, swimming) combined with light strength training are ideal. However, avoid overexertion, especially if you are still feeling very weak.
Heat and alternating showers: If you freeze quickly, warm baths, saunas or an infrared heat lamp can make you feel better. Alternating showers (alternating between hot and cold) in the morning can stimulate your circulation. However, make sure you wrap up warm afterwards.
Home remedies for skin and hair: Moisturizing creams or natural oils (e.g. coconut oil) after showering help to combat dry skin. You could treat an itchy, dry scalp with warm oil treatments (e.g. gently massage in olive or coconut oil and leave on). Mild baby shampoo or special shampoos for dry scalps prevent additional drying out. In the case of severe hair loss, it is worth visiting a dermatologist - sometimes accompanying measures such as biotin preparations or scalp solutions (e.g. with panthenol) can support hair growth until the thyroid gland is readjusted.
Naturopathic support: In naturopathy, various medicinal plants and remedies are recommended to support the thyroid gland. For example, taiga root (Eleutherococcus senticosus) is considered an adaptogenic tonic, which is said to mobilize strength in cases of exhaustion. Ashwagandha (sleepberry) is an Ayurvedic herb that has been shown in a study to have antioxidant effects and support thyroid function [16]. Ginger and turmeric as anti-inflammatory spices also have a reputation for gently stimulating the metabolism. But remember: no herb can replace the missing hormone - naturopathic remedies are more for general stabilization. Discuss such remedies with your doctor, especially if you are already taking thyroid medication.
Avoid harmful substances: Smoking has an unfavorable effect on the thyroid gland (it can, for example, increase autoimmune processes). If you smoke, it is advisable to stop - and not just for your thyroid. Excessive alcohol consumption should also be avoided. Environmental toxins such as heavy metals or certain chemicals (e.g. PCBs, bisphenol A) are suspected of disrupting endocrine functions. It helps to pay attention to a low-pollutant environment and diet (organic food, less plastic, etc.).

All these measures can help you feel better despite having an underactive thyroid. Make the thyroid gland "strong", so to speak, by helping the body to cope better with the slowed metabolism. A healthy lifestyle can also have a positive effect on the immune system - particularly important for Hashimoto's. Nevertheless, these measures do not replace the necessary medical therapy, but offer valuable support in everyday life.

Nutrition and micronutrients for hypothyroidism

"You are what you eat" - this saying also applies to the thyroid gland. A balanced diet ensures the supply of all necessary micronutrients required for thyroid function. These are particularly important:

Iodine: The trace element iodine is essential for the formation of T3 and T4 [3]. Iodine deficiency can lead to hypothyroidism and goitre formation. In Germany, it is recommended to consume approx. 200 µg of iodine per day (adults). Iodine is mainly found in sea fish, seafood and seaweed (e.g. kelp/brown algae), and in smaller quantities in milk and eggs. Iodized table salt is also an important source. Therefore, make sure you eat fish regularly (once or twice a week) and use iodized salt for cooking to prevent hypothyroidism caused by iodine deficiency. Note: If you are known to have Hashimoto's thyroiditis, extreme doses of iodine should be avoided, as too much iodine can trigger inflammation [1].
Selenium: Selenium is another key nutrient for the thyroid gland. It is a component of the deiodase enzymes that convert T4 into active T3 [3]. Selenium also protects the thyroid gland from oxidative stress as it is incorporated into antioxidant enzymes (glutathione peroxidase) [3]. Good sources of selenium are Brazil nuts (just 2-3 Brazil nuts a day cover the requirement of ~60-70 µg), fish, meat and wholegrain cereals. In studies, selenium supplementation in Hashimoto's patients was able to reduce thyroid antibody titres and improve well-being [17]. Therefore, an additional intake of approx. 100-200 µg selenium (e.g. as sodium selenite or selenium yeast) is often recommended, especially in the case of autoimmune causes. Important: Do not overdose, as too much selenium can be toxic - keep to the recommended amount.
Iron: Iron deficiency can impair thyroid function as iron is required for the synthesis of thyroid hormones and for the conversion of T4 to T3 [3]. In addition, hypothyroidism itself is often accompanied by mild anemia. Make sure you get enough iron (meat, pulses, green vegetables). If a deficiency is detected, an iron supplement may be useful.
Vitamin D: Many people with hypothyroidism - especially those with Hashimoto's - have low vitamin D levels. Vitamin D plays a role in the immune system and cell health. A deficiency is associated with autoimmune diseases. Have your vitamin D levels checked and speak to a doctor about supplementation during the winter months.
Zinc and other B vitamins: Zinc is a cofactor in many metabolic reactions and is also important for the thyroid gland. It is found in meat, nuts and oatmeal. A slight zinc deficiency can increase hair loss and tiredness - temporary zinc supplementation (e.g. 10-15 mg/day) may be helpful. Vitamin B12 is also often low in autoimmune thyroiditis (possibly due to associated gastritis). A deficiency should be compensated as it can cause fatigue and neurological symptoms.
Antioxidants: Fresh fruit and vegetables provide vitamins (A, C, E) and secondary plant substances that have an antioxidant effect. In Hashimoto's, inflammatory processes produce free radicals, which can further damage the thyroid gland. A colorful, plant-based diet helps to mitigate oxidative damage. Brazil nuts (selenium), berries (vitamin C), carrots/pumpkin (beta-carotene, precursor of vitamin A) and green leafy vegetables are particularly recommended. Spices such as turmeric and green tea also provide antioxidants.

Good to know: There is no general "thyroid diet" - it is more important to ensure an adequate supply of the nutrients mentioned and to avoid extremes. Although certain diets (e.g. gluten-free for Hashimoto's) are sometimes discussed; avoiding gluten is indeed essential for coeliac disease (gluten intolerance), there is otherwise no clear evidence that a gluten-free diet improves Hashimoto's thyroiditis unless coeliac disease is present. Nevertheless, some patients report a subjective improvement when omitting gluten or milk - you can try this out individually, but you should ensure a balanced nutrient intake.

Food supplements for the thyroid gland

Dietary supplements can be useful to support the diet in order to supply the thyroid gland with important nutrients. The following supplements are often recommended in connection with an underactive thyroid:

Brown algae (kelp): Kelp is a marine algae and is naturally very rich in iodine. As a dietary supplement for the thyroid gland, kelp is offered in the form of powder or capsules to increase the iodine intake. As iodine is essential for hormone production [3], kelp can be helpful in cases of hypothyroidism caused by iodine deficiency. However, caution is advised: The iodine content in kelp products can vary greatly and overdosing is possible. Too much iodine can worsen the situation, especially in the case of Hashimoto's [1]. You should therefore only take kelp according to the recommended dosage (often ~150-200 µg iodine per day). High-dose kelp cures on your own are not advisable. However, with the correct dosage, kelp can provide natural support to compensate for a mild iodine deficiency.
Selenium: As mentioned above, a selenium supplement is often recommended in cases of proven selenium deficiency or Hashimoto's. Doses of 50-200 µg selenium (e.g. as sodium selenite) daily for several months are common. Studies show that selenium supplements can reduce inflammatory parameters (TPO antibodies) and improve well-being [17]. It is important not to take very high doses uncontrolled - more than 300 µg per day should be avoided to prevent side effects. Regular monitoring of selenium levels is advisable with long-term intake. With a normal mixed diet (including Brazil nuts), a severe selenium deficiency is rare, but vegetarians/vegans or people with absorption disorders in particular can benefit.
Thyme (Thymus vulgaris): Thyme is known to many as a culinary and medicinal herb (e.g. for coughs). Less well known: Thyme is also associated with thyroid health in herbal medicine. Animal studies suggest that thyme extract may have protective effects on the thyroid gland [18] - presumably through antioxidant ingredients (thymol, flavonoids) and anti-inflammatory effects. Thyme itself does not provide iodine or selenium, but could support the metabolism as an accompanying phytotherapy. Some naturopathic thyroid preparations therefore contain thyme. Thyme tea can be drunk as a home remedy - but the direct effect on the thyroid gland in humans has not yet been clearly scientifically proven. However, it does no harm as thyme is a generally beneficial herb (antiseptic for the respiratory tract, aids digestion). It can therefore be used as a supplement, but miracles should not be expected.
Omega-3 fatty acids: Fish oil or algae oil capsules provide omega-3 fats (EPA/DHA), which have an anti-inflammatory effect. In the case of Hashimoto's, omega-3s can help to reduce autoimmune inflammation, although data on this is limited. Overall, they support the heart and blood vessels - which is also beneficial in hypothyroidism (elevated cholesterol levels!).
B-complex vitamins: A vitamin B complex can be useful, as B vitamins (especially B12, B6) play a role in fatigue, depression and nerve function. Especially if a deficiency has been detected (e.g. low B12 in Hashimoto's patients with autoimmune gastritis), substitution should be considered. A balanced B vitamin status supports the energy metabolism.

Important for all thyroid supplements: quality and dosage. Stick to the recommended quantities and choose products that have been tested as far as possible. As we have seen, too much can be problematic (keyword iodine/selenium). Use food supplements specifically to fill proven gaps or to provide therapeutic support. They do not replace drug therapy, but - if used correctly - can make a valuable contribution to supplying the thyroid gland with everything it needs to function properly.

Special case: hypothyroidism in dogs

Not only humans, but also dogs can suffer from hypothyroidism. Hypothyroidism in dogs (canine hypothyroidism) is relatively common, especially in middle-aged dogs. Similar to humans, over 90% of cases are caused by a problem in the thyroid gland itself (primary hypothyroidism) [19]. This is usually caused by a condition known as lymphocytic thyroiditis, in which the immune system attacks the dog's thyroid gland - similar to Hashimoto's [19]. Over time, functional thyroid tissue is lost and the dog develops a hormone deficiency. Other rare causes are thyroid tumors or disorders of the pituitary gland (secondary hypothyroidism).

How do you recognize hypothyroidism in dogs? The symptoms are similar to those in humans, but are often initially overlooked by the owner because they come on gradually. Common signs are

Poor performance and listlessness: the dog often seems tired, moves less and sleeps a lot. He seems "sluggish" and doesn't like to play as much.
Weight gain: Despite eating normal food, the dog gains weight. Many hypothyroid dogs tend to be overweight as the basal metabolic rate drops.
Skin and coat changes: Hair loss is very typical - especially on the sides of the body, back, tail ("rat tail") and hind legs [20]. The coat becomes thin and dull, the skin can become pigmented and scaly [20]. The affected areas usually do not itch, unless secondary infections develop [20].
Cold intolerance: Many affected dogs increasingly seek out warm places, do not like the cold and freeze quickly (e.g. shivering).
Bradycardia: Veterinarians often note a slowed heartbeat. The circulation is generally somewhat reduced.
Neurological abnormalities (rare): In severe cases, dogs may develop balance problems, weakness in the hind legs or even seizures. However, this is rare and usually reversible with treatment.

Diagnosis: Analogous to humans, the blood is examined for TSH, T4 and, if necessary, antibodies [21]. Diagnosis requires experience, as other diseases can falsify the thyroid values ("euthyroid sick syndrome"). Therefore, symptoms and possibly a therapy test are also included in the diagnosis.

Treatment: Dogs receive the same active substance as humans - levothyroxine (T4) [22]. The hormones are usually administered for life. With the correct dosage, the symptoms often improve quickly: the dog becomes more active, the coat grows back and skin problems subside [23]. Complete coat regeneration can take several months [23]. Regular checks and dose adjustments are important. With adequate treatment, the prognosis is very good - life expectancy remains normal [24]. However, if left untreated, the condition progressively worsens.

Conclusion for dog owners: If your four-legged friend seems sluggish, gains weight or develops skin problems, have an underactive thyroid checked. The treatment is simple, effective and can help your dog to enjoy life more.

XTRAFUEL Thyroid Complex - support for your thyroid gland

To support your thyroid in a natural way, a targeted dietary supplement can be useful. One recommended option is our XTRAFUEL Thyroid Complex. The product combines three important components for thyroid health:

Thyme herb powder: Contains valuable phytochemicals such as thymol and flavonoids. Thyme is traditionally valued in naturopathy [18].
Brown algae powder (kelp): Provides natural iodine from algae. This supports the normal production of thyroid hormones [3] and helps to prevent iodine deficiency - a crucial factor for a healthy thyroid gland.
Sodium selenite: Provides the body with selenium, which is required for the conversion of T4 to T3 and protects the thyroid gland from oxidative damage [3]. Selenium contributes to normal thyroid function and can be particularly helpful in autoimmune thyroiditis.

With this selected combination, the XTRAFUEL Thyroid Complex can strengthen your thyroid gland and provide nutritional support for healthy thyroid function. Of course, such a supplement does not replace medical therapy, but it can help to ensure that your thyroid gland is optimally supplied with essential micronutrients as part of a holistic approach.

FAQ - Frequently asked questions

What to do with hypothyroidism?

Answer: The first step is always to see a doctor. If you notice symptoms of an underactive thyroid (tiredness, freezing, weight gain, hair loss, etc.), have your thyroid levels checked in the blood. If the diagnosis is confirmed, treatment with thyroid hormone tablets (levothyroxine) is usually started to compensate for the deficiency. You can also do a few things yourself: Make sure you eat a diet rich in iodine and selenium (sea fish, iodized salt, Brazil nuts), take it easy, reduce stress and make sure you get enough sleep. Micronutrient supplements can help if you have gaps in your diet. Important: Stick to your doctor's treatment plan, take your medication reliably and attend check-ups. With the right treatment and an adapted lifestyle, you can get hypothyroidism under control.

Can hypothyroidism be treated naturally?

Answer: Mild hypothyroidism (e.g. subclinical hypothyroidism) can sometimes be positively influenced by diet and lifestyle under medical supervision. An adequate supply of iodine and selenium is essential. Naturopathic measures - such as taking certain herbs (e.g. ashwagandha, ginger, thyme) or relaxation techniques to reduce stress - can have a supportive effect. Home remedies for hypothyroidism (such as warm compresses for cold sensitivity, coconut oil for dry skin) alleviate some symptoms. Nevertheless, if the hypothyroidism is severe, there is usually no way around taking thyroid hormones. Natural treatment methods can usefully supplement conventional therapy, but cannot completely replace it. So talk to your doctor about whether a temporary attempt at therapy without hormones is justifiable in your particular case - and monitor your values regularly.

Can I buy natural thyroid hormones over the counter?

Answer: No, genuine thyroid hormones - whether of synthetic or natural origin - are subject to prescription in Germany. Natural thyroid hormones usually refer to animal thyroid extracts (NDT) from pigs. These preparations are only available on prescription in Germany and are only prescribed by doctors in certain cases. On the other hand, thyroid supplements containing iodine, selenium or herbs, for example, which are intended to support thyroid function, are available without a prescription. You can purchase such products freely. However, you are not receiving hormones, but nutrients. If you see online offers that supposedly offer "thyroid hormones without a prescription", be careful - these are usually illegal or dubious products. Always consult a doctor before taking any hormones.

How can you stop hair loss with hypothyroidism?

Answer: The most effective way is to treat the underlying hypothyroidism. As soon as your thyroid hormone levels return to normal under therapy, hormone-induced hair loss usually stops [5]. However, the hair needs some time to grow back - often several months. You can support this by eating a diet rich in protein and nutrients (e.g. biotin, zinc, iron, vitamin D). Avoid aggressive hair treatments and use mild care products to protect the scalp. A gentle scalp massage can stimulate blood circulation. Biotin or silica supplements are also possible - ideally in consultation with your doctor. Patience is important: with well-adjusted thyroid therapy, the hair follicles usually regenerate on their own.

Which food supplements help the thyroid gland?

Answer: Iodine and selenium are particularly important - these two trace elements are essential for healthy thyroid function. Iodine ensures that your body can produce enough thyroid hormones [3], and selenium is needed for the conversion and protection of the thyroid gland [3].

If you rarely eat sea fish or do not use iodized table salt, an iodine supplement (for example in the form of kelp algae in controlled doses) may be useful for you. If you have Hashimoto's or a proven selenium deficiency, taking selenium (e.g. 100-200 µg sodium selenite) can also help to support your thyroid gland.

Other dietary supplements that can benefit your thyroid are zinc (for the metabolism and immune system) and vitamin D (especially if you have a deficiency). Many people also take special thyroid complex preparations that contain a combination of iodine, selenium, herbs (such as thyme) and sometimes B vitamins.

Important for you: Use food supplements selectively and avoid overdosing. If in doubt, have your blood values checked so that you can be sure whether you really need them. When used correctly, food supplements can provide your thyroid gland with the nutrients it needs.

What thyroid levels are normal?

Answer: Two values are particularly important in thyroid diagnostics: TSH and fT4. As a rough guide, the following normal ranges apply (may vary slightly depending on the laboratory):

TSH (thyroid-stimulating hormone): Normal range approx. 0.4-4.0 mIU/L [2]. An elevated TSH value (> 4.0) indicates hypofunction, a very low value indicates hyperfunction.
free T4 (fT4): depending on the measurement method, around 10 - 23 pmol/L (0.8 - 1.8 ng/dl). In the case of hypofunction, fT4 is usually low (below normal or lower). Important: TSH and fT4 should be considered together. Example: An elevated TSH with still normal fT4 indicates an incipient hypofunction (subclinical). An elevated TSH with clearly low fT4 indicates a clear hypofunction (manifest).
Free T3 (fT3): Norm approx. 3.5 - 7.8 pmol/L (or 2.3 - 4.4 pg/ml). fT3 is often still within the normal range in hypothyroidism, as the body tries to produce enough T3 from the low T4. In advanced cases, however, fT3 also falls. For routine diagnostics, fT3 is less important than TSH and fT4.

In addition, TPO antibodies (< 35 IU/ml) or thyroglobulin antibodies (< 115 IU/ml) are measured if Hashimoto's is suspected. Cholesterol or liver values may also be altered in a manner typical of hypofunction [14]. Important: The interpretation is always carried out in connection with symptoms - slightly deviating values do not necessarily require treatment, and normal values do not rule out an incipient functional disorder.

How is hypothyroidism treated in dogs?

Answer: Just like in humans, dogs with hypothyroidism are given the missing hormone in the form of a medication. As a rule, once or twice a day levothyroxine (T4) is administered in tablet form once or twice a day [25]. The dosage depends on the body weight and is adjusted individually by the vet. At the beginning, close blood checks are carried out to determine the appropriate dose and to avoid over- or underdosing. As soon as the values are stable, check-ups every 6-12 months are usually sufficient.

Already after 2-4 weeks many dogs show a noticeable improvement: they become more active, the coat begins to grow back and skin problems improve [24]. However, until the coat is fully regenerated, it can take 3-6 months months [23]. Treatment is usually necessary for life - discontinuation almost always leads to a relapse.

In addition, dog owners should pay attention to a balanced, possibly calorie-adjusted diet (especially for overweight animals) and ensure that the animal is not overburdened at the start of treatment. With the correct adjustment of the hormone and a little patience, dogs with hypothyroidism can lead a completely normal, healthy and happy life.

Bibliography:

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[2] TSH Levels: Low to high ranges, symptoms, and what they mean - Medical News Today
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[3] Role of iodine, selenium and other micronutrients in thyroid function and disorders - PubMed
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[5] Hypothyroidism: Signs and Symptoms - Healthline
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[11-13] Hypothyroidism: Signs and Symptoms - Healthline
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[14] Hypothyroidism - StatPearls - NCBI Bookshelf
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[15] Desiccated thyroid extract compared with levothyroxine in the treatment of hypothyroidism: a randomized, double-blind, crossover study - PubMed
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[16] 8 herbs that may improve thyroid health: What to know - Medical News Today
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[17] The Effects of Selenium Supplementation in the Treatment of Autoimmune Thyroiditis: An Overview of Systematic Reviews - PMC
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[18] Role of Thyme Extract against Some Biochemical Alterations Induced by Propylthiouracil in Male Rats - Journal of Food and Nutrition Research
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[19-25] Hypothyroidism - Cornell University College of Veterinary Medicine
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