Hypothyroidism, also known as underactive thyroid, is a medical condition in which your thyroid does not produce sufficient hormones. Since these hormones are crucially involved in regulating your metabolism, a deficiency often leads to a range of symptoms – including weight gain, fatigue, and generally slowed digestion. People with an underactive thyroid know the problem: despite diet and exercise, the weight just doesn't seem to drop off.
But there is hope. In recent years, so-called GLP-1 receptor agonists, particularly semaglutide, have attracted a lot of attention in the medical world because they can offer effective support for weight loss. In this article, you will learn how these medications work, what you need to keep in mind, how you can integrate them into your daily life, and whether it is even possible to lose weight with an underactive thyroid while using them.
The thyroid and thyroid hormones
The thyroid is a small but extremely important gland in the body. It is located at the front of your neck, just below the larynx, and is butterfly-shaped. Despite its small size, it plays a central role in many bodily functions, especially in regulating metabolism. This occurs through the production of the hormones L-thyroxine and triiodothyronine, which influence almost every cell in the body.
What do thyroid hormones do?
Thyroid hormones T3 and T4 influence the speed at which your body generates and uses energy from food. They control how quickly your cells convert nutrients into energy, how active your nervous system is, and how efficiently your body produces heat. Essentially, these hormones regulate how fast or slow your metabolism works.
- T4 (L-thyroxine): This is the most frequently produced thyroid hormone and serves as a kind of storage hormone. In the body, T4 is converted into T3.
- T3 (triiodothyronine): T3 is the biologically active hormone and is directly responsible for boosting the metabolism. It influences heart rate, body temperature, digestion, and energy production.
The importance of a balanced hormone level
For a healthy metabolism, it is crucial that the thyroid produces sufficient T4 and T3. If hormone production is too low, as in the case of an underactive thyroid, all bodily functions slow down. This leads to symptoms such as weight gain, fatigue, sensitivity to cold, and sluggish thinking.
A normal thyroid hormone level is essential for:
- Metabolic rate: The speed at which your body burns calories. If the thyroid is not working properly, it slows down the metabolism and unwanted kilos quickly land on your hips.
- Body temperature: Keeps you warm by regulating heat production in the cells.
- Heart function: Influences how fast and strongly your heart beats.
- Digestion: Influences the speed of digestive processes.
- Nervous system: Keeps your brain and nerves active and high-performing.
How an impaired thyroid function affects the metabolism
First, it is important to understand exactly what happens in your body during hypothyroidism.
When your thyroid does not produce enough hormones, your entire metabolism slows down. This leads to you burning fewer calories, even with consistent food intake. People with hypothyroidism often notice that they have difficulty losing weight despite diet and exercise. Fat burning is reduced, and the body tends to store fat and water, which leads to weight gain and fluid retention.
Causes of an underactive thyroid
The causes of an underactive thyroid are diverse and can be caused by both genetics and environmental factors. Here are the most common causes:
1. Autoimmune diseases: Hashimoto's thyroiditis
The most common cause of an underactive thyroid is Hashimoto's thyroiditis, an autoimmune disease. With this condition, the immune system mistakenly attacks the thyroid, which leads to chronic inflammation and long-term destruction of the thyroid tissue. As a result, the thyroid can produce fewer hormones. Hashimoto's is particularly common in women and usually develops in middle age.
2. Iodine deficiency
Iodine is an essential mineral that is needed for the production of thyroid hormones. An iodine deficiency can impair the thyroid's ability to produce enough hormones. In many countries, including Germany, the supply of iodine has been improved through iodized table salt, but in areas with low iodine levels in the soil or with insufficient iodine intake through food, a deficiency can still occur.
3. Thyroid surgeries
Sometimes a surgical removal of part or all of the thyroid is necessary, for instance in cases of thyroid nodules, thyroid cancer, or severe Graves' disease (a form of hyperthyroidism). If too much thyroid tissue is removed during this process, the production of thyroid hormones can no longer be maintained, which leads to an underactive thyroid.
4. Radiation therapy
Radiation of the neck, for example to treat cancer (such as lymphomas or head and neck tumors), can damage the thyroid and impair its ability to produce sufficient hormones. Patients who were treated for an overactive thyroid with radioactive iodine therapy can also later develop an underactive thyroid.
5. Congenital hypothyroidism
In some people, an underactive thyroid is present at birth. This congenital hypothyroidism occurs when the thyroid is either not present at all, only partially, or not correctly developed. This form of hypothyroidism is usually detected in newborns as part of a routine screening, as untreated hypothyroidism leads to severe developmental delays.
6. Medication
Certain medications can influence thyroid function and cause hypothyroidism. These include medications such as amiodarone (a medication for heart rhythm disorders), lithium (for treating bipolar disorders), and certain cancer medications. These medications can inhibit hormone production or damage thyroid tissue.
7. Pregnancy
Some women develop an underactive thyroid during or after pregnancy, known as postpartum thyroiditis. This temporary inflammation of the thyroid occurs about 6 to 12 months after giving birth and can lead to a permanent underactive thyroid in some women. Hormonal changes and the immune system play a role here.
Thyroid hormones and weight regulation
Since thyroid hormones are directly linked to energy consumption and fat burning, a healthy thyroid is crucial for weight management. If hormone levels are too low, it is difficult to burn calories, even if you stick to a diet or exercise regularly. It is therefore important that an underactive thyroid is detected and treated early in order to minimize these negative effects on the metabolism.
Typical symptoms of an underactive thyroid:
- Weight gain or difficulty losing weight
- Fatigue and exhaustion
- Sensitivity to cold
- Difficulty concentrating
- Dry skin and hair
So, before you consider a weight-loss injection, it is crucial that your thyroid levels are checked by a doctor and that you are potentially treated with levothyroxine (a synthetic thyroid hormone). Only then can your metabolism be brought back to a normal level.
Nutrition for an underactive thyroid: Tips for optimally supporting the metabolism
With an underactive thyroid, proper nutrition is a decisive factor in supporting the metabolism and making weight loss easier. Because the thyroid produces too few hormones and the entire metabolism is slowed down, many sufferers find it difficult to maintain or reduce their weight. However, an adjusted diet can help to optimally provide for the body and promote fat loss. Here are some important nutrition tips that people with an underactive thyroid should keep in mind:
Balanced diet and nutrient intake
A balanced diet is the key to providing the body with all the necessary nutrients that are important for thyroid function and metabolism. The following nutrients, in particular, play a decisive role in hypothyroidism:
- Iodine: This trace element is essential for the production of thyroid hormones. Iodine deficiency can worsen the symptoms of an underactive thyroid. Good sources of iodine are seafood, seaweed, and iodized table salt.
- Selenium: Selenium is another important trace element that contributes to the conversion of the inactive thyroid hormone T4 into the active T3. Selenium-rich foods such as Brazil nuts, eggs, and sunflower seeds should therefore be a regular part of the menu.
- Zinc: Zinc supports thyroid function and metabolism. Zinc-rich foods such as legumes and whole-grain products should also be part of a balanced diet.
- Sufficient protein intake: Protein is an important nutrient that boosts the metabolism and helps with fat loss. It also supports the maintenance of muscle mass, which is particularly important in hypothyroidism, as a slowed metabolism can lead to the body breaking down muscle mass. Good sources of protein are fish, legumes, eggs, and dairy products.
- Carbohydrates in moderation – do not avoid: While many diets recommend drastically reducing carbohydrates, this can be counterproductive for an underactive thyroid. The thyroid needs carbohydrates for efficient hormone production. A balanced amount of carbohydrates – especially from whole-food sources – is therefore important so as not to further burden the metabolism. Whole-grain products, quinoa, oatmeal, and sweet potatoes are good sources of complex carbohydrates.
Anti-inflammatory foods: How they can help with an underactive thyroid
Anti-inflammatory foods play a central role in supporting the body, especially in people with an underactive thyroid, which is frequently associated with thyroid inflammation, such as in the most common cause of hypothyroidism, the autoimmune disease Hashimoto's thyroiditis, where the immune system attacks the thyroid and triggers inflammation.
Why are anti-inflammatory foods important?
In autoimmune diseases, the immune system enters a chronic state of inflammation. These constant inflammatory processes strain not only the thyroid but the entire body, and often lead to further health problems such as fatigue, weight gain, and joint pain.
By regularly incorporating anti-inflammatory foods into your menu, you can lower the level of inflammation in the body. This has a positive effect on the metabolism and helps to better regulate weight, as the thyroid is relieved and metabolic processes can improve.
Important anti-inflammatory foods for hypothyroidism:
- Fatty fish (e.g., salmon, mackerel, herring): Fatty fish are rich in omega-3 fatty acids. These fatty acids can reduce inflammation and positively influence the immune system. Studies have shown that omega-3 fatty acids can inhibit pro-inflammatory molecules that play a role in autoimmune diseases like Hashimoto's. Furthermore, they support heart health, which is an advantage for people with an underactive thyroid, as they often have an increased risk of cardiovascular diseases.
- Nuts and seeds: Nuts like walnuts and seeds like chia and flax seeds are also excellent sources of omega-3 fatty acids, particularly in plant-based form as alpha-linolenic acid (ALA). Furthermore, nuts and seeds contain selenium, another essential trace element needed for thyroid function and the conversion of the thyroid hormone T4 to T3. A deficiency in selenium is frequently observed in people with Hashimoto's thyroiditis, which can intensify inflammatory processes.
- Olive oil: especially extra virgin olive oil, is one of the best sources of monounsaturated fatty acids and polyphenols, which have a strong anti-inflammatory effect. The polyphenols in olive oil block pro-inflammatory molecules in the body, and the fatty acids support cell health. Regular consumption of olive oil can contribute to lowering the general level of inflammation.
- Green leafy vegetables: e.g., spinach, kale, chard are rich in antioxidants, vitamins, and minerals that support the body in the fight against inflammation. These types of vegetables contain, among other things, high amounts of vitamin C, vitamin K, and magnesium, all of which possess anti-inflammatory properties. Magnesium is particularly important, as many people with an underactive thyroid suffer from a deficiency, which in turn can worsen the symptoms of the condition. Furthermore, green leafy vegetables are low-calorie and rich in fiber, which support digestion and stabilize blood sugar levels, which is important for avoiding cravings.
- Berries: are little powerhouses full of antioxidants that can fight free radicals and reduce inflammation in the body. Blueberries and other berries contain polyphenols and anthocyanins, which have an anti-inflammatory effect and strengthen the immune system. Regular consumption of berries can help to lower inflammation levels in the body and thus support the metabolism in cases of an underactive thyroid. Berries are also low-calorie and rich in fiber, making them an ideal aid for weight loss.
- Turmeric: The spice turmeric contains the active ingredient curcumin, which acts as a powerful anti-inflammatory and antioxidant. However, because it is difficult for the body to absorb, it is recommended to consume turmeric together with pepper and healthy fats to increase the bioavailability of curcumin. Many studies show that curcumin can alleviate chronic inflammation.
Weight loss with an underactive thyroid
The hormone GLP-1 (glucagon-like peptide 1) plays a key role in regulating your blood sugar level and your appetite. It is produced in the gut and signals to your brain that you are full. Furthermore, it delays stomach emptying, which leads to a longer feeling of satiety. These mechanisms make GLP-1 analogues, such as semaglutide, a promising approach for supporting weight loss.
Semaglutide acts as a GLP-1 receptor agonist, which means it has similar effects in the body to the natural GLP-1 hormone. It is administered in the form of a weekly injection and has proven to be particularly effective in reducing body weight. It not only lowers appetite but also helps to stabilize blood sugar levels – a benefit that is particularly significant for people with prediabetes or type 2 diabetes, who often also struggle with obesity.
How GLP-1 and semaglutide can help with weight loss
GLP-1 (glucagon-like peptide 1) is released as a naturally occurring hormone in the body into the gut after food intake and fulfills several important functions that play an essential role in weight loss. Semaglutide is a synthetic GLP-1 receptor agonist that imitates and reinforces the effect of the natural GLP-1 hormone in the body in order to support weight loss.
GLP-1 has several effects that make it a valuable tool for weight management:
- Delayed gastric emptying: GLP-1 ensures that food remains in the stomach for longer. This makes you feel full for longer and prevents hunger from returning as quickly. A prolonged feeling of satiety helps you consume less food, which leads to a reduction in calories over the long term.
- Appetite regulation: GLP-1 acts on the satiety center in the brain, specifically the hypothalamus, and sends signals that reduce the feeling of hunger. This makes it easier to avoid large portions or unhealthy snacks and control calorie intake.
- Blood sugar regulation: GLP-1 stimulates insulin production when blood sugar levels rise after a meal, while simultaneously inhibiting the release of glucagon (a hormone that raises blood sugar). This leads to more stable blood sugar levels, which can prevent cravings.
Why is semaglutide particularly helpful for hypothyroidism?
People with hypothyroidism have a slow metabolism, which makes losing weight more difficult. Semaglutide can play an important role here by not only reducing appetite but also increasing energy expenditure in the body. Although it has no direct effect on the thyroid, semaglutide can make weight loss easier by improving metabolic functions, even if thyroid metabolism is slowed down.
However, semaglutide should never be used as a replacement for the treatment of hypothyroidism. Your first step should always be to stabilize your thyroid levels. Only once this has been achieved can semaglutide be considered as a supplementary measure to facilitate weight loss.
How to use GLP-1 medications safely
If you are considering semaglutide or another GLP-1 medication, there are a few important points to keep in mind:
- Regular medical monitoring: Semaglutide is prescription-only, and it is important that you coordinate your treatment closely with your doctor.
- Use as part of a comprehensive plan: Semaglutide is most effective when used in combination with a low-calorie diet and regular exercise. It will help you control your hunger and feel full faster, but a healthy lifestyle remains the basic requirement for long-term weight loss.
- Slow dose escalation: To minimize side effects, the dose of semaglutide is increased gradually. This gives your body time to get used to the medication.
- Long-term use: Semaglutide is designed to be taken over a longer period of time to achieve sustainable success. Abrupt discontinuation can cause appetite to return and the lost weight to be regained.
Conclusion on weight loss with hypothyroidism using GLP-1 medications
People suffering from hypothyroidism often have difficulty losing weight. Due to hypothyroidism, the thyroid produces too few hormones, including the important thyroxine, which slows down the entire metabolism and thus makes weight loss more difficult. The thyroid is central to almost all of the body's metabolic processes and regulates energy consumption. When hormone production is reduced, it often leads to unwanted weight gain because the body no longer burns many calories efficiently.
Despite having an underactive thyroid, there are ways to lose weight healthily. Medications like thyroxine in tablet form are often prescribed to compensate for the hormone deficiency. However, those affected often find it difficult to lose weight even when their medication has been adjusted. This is because hypothyroidism slows down the metabolism, making it harder to break down stored fat. Affected individuals who want to lose weight despite having an underactive thyroid should focus on a balanced diet and regular physical activity.
According to the German Society of Endocrinology, the appetite center is influenced by hypothyroidism, which leads to satiety mechanisms no longer functioning correctly. This makes weight loss even more difficult, as the reduced thyroid hormones slow the metabolism down even further. With the right therapy, consisting of a combination of medication, an adjusted diet, and exercise, it is possible to successfully lose weight even with this condition.
Good therapy truly enables those affected to control symptoms and lose weight. In combination with regular exercise, it not only promotes calorie consumption but also supports the breakdown of fat. GLP-1 medications can additionally help support weight loss in hypothyroidism, as they influence the appetite center and thus increase the feeling of satiety, which is particularly important when satiety mechanisms are no longer functioning correctly due to hypothyroidism.
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