Thyroid Gland: How to Treat Hypothyroidism Effectively and Safely
Hypothyroidism is a condition in which the thyroid gland does not produce enough hormones. These hormones play a key role in regulating metabolism, energy, and many other vital functions of the body. A lack of thyroid hormones can lead to a wide range of symptoms, from fatigue and weight gain to heart and reproductive problems. Effective treatment of hypothyroidism is crucial for maintaining quality of life and preventing serious complications.
What is Hypothyroidism and Its Causes?
Hypothyroidism is characterized by decreased thyroid function, leading to a deficiency of thyroid hormones. The most common cause of hypothyroidism is autoimmune thyroid disease (AITD), in which the immune system mistakenly attacks and damages the thyroid gland [3]. This condition is particularly common among women of reproductive age [3].
In addition to autoimmune processes, hypothyroidism can be caused by other factors, such as:
- Surgical removal of all or part of the thyroid gland.
- Radioactive iodine used to treat hyperthyroidism or thyroid cancer.
- Certain medications. For example, the dual GLP-1/GIP agonist tirzepatide, used to treat obesity, has been linked to the development or worsening of thyroid diseases, including nodular formations, goiter, and drug-induced thyroiditis (DIT) [1].
- Iodine deficiency (although this is a less common cause in developed countries).
- Congenital abnormalities of the thyroid gland.
Symptoms of hypothyroidism can be nonspecific and develop gradually, making timely diagnosis difficult. They include fatigue, weight gain, constipation, dry skin, hair loss, cold sensitivity, muscle aches, and depression.
Standard Approaches to Hypothyroidism Treatment
The primary method of treating hypothyroidism is hormone replacement therapy with the synthetic hormone levothyroxine (L-T4) [3, 6]. Levothyroxine is identical to the natural thyroxine (T4) hormone produced by the thyroid gland and helps restore normal hormone levels in the body. The dosage of levothyroxine is selected individually for each patient and adjusted regularly based on blood levels of thyroid-stimulating hormone (TSH).
The goal of treatment is to achieve and maintain TSH levels within the normal range, which indicates adequate thyroid function. For most patients, this eliminates symptoms and prevents complications. However, there are certain groups of patients for whom TSH target ranges may differ, such as women planning a pregnancy [3, 6].
A particular challenge is the treatment of subclinical hypothyroidism (SH), in which TSH levels are elevated but free T4 levels remain within the normal range. Recommendations for treating SH, especially at lower TSH thresholds (e.g., 2.5 to 4.0 mIU/L), remain a subject of debate and can vary depending on the clinical situation, patient age, and comorbid conditions [3].
Hypothyroidism and Women's Reproductive Health
Autoimmune thyroid diseases (AITDs) are the most common autoimmune disorders among women of reproductive age and are closely associated with infertility and adverse outcomes of assisted reproductive technologies (ART) [3]. Severe thyroid dysfunction can lead to menstrual irregularities and infertility by affecting the hypothalamic-pituitary-ovarian axis and reproductive organs [6].
The importance of screening and treating hypothyroidism in women planning pregnancy or undergoing ART is emphasized in several studies. For women receiving levothyroxine treatment, it is recommended to maintain a TSH level below 2.5 mIU/L before starting ART [6]. With a TSH level above 4.0 mIU/L, a decrease in fertilization rates, embryo quality, and live birth rates is observed [6].
Despite widespread recommendations for levothyroxine treatment when TSH is >4.0 mIU/L, the benefits of treatment at lower thresholds remain controversial [3]. Furthermore, immunomodulatory therapy, such as glucocorticoids and intravenous immunoglobulin, has shown uncertain efficacy in improving ART outcomes in women with AITD [3]. This highlights an urgent need for standardized diagnostic criteria and therapeutic approaches to optimize fertility outcomes in women with AITD [3].
It is important to note that even after normal thyroid function is restored, fertility problems may persist, and in such cases, surgery or ART may be required to achieve pregnancy [6]. Ovarian stimulation, which is the initial stage of ART, can place a strain on the thyroid gland, potentially leading to (permanent) hypothyroidism in women with thyroid autoimmunity or those already receiving thyroid hormone therapy [6].
The Impact of New Medications on Thyroid Function
With the advent of new therapeutic agents for various diseases, it is important to consider their potential impact on the endocrine system, particularly the thyroid gland. For instance, tirzepatide, a dual GLP-1 and GIP receptor agonist, has shown high efficacy in combating obesity. However, studies have identified potential thyroid-related side effects [1].
A retrospective analysis of medical records of patients treated with tirzepatide for 12 months showed that 5.3% of 527 patients developed or progressed in thyroid disease [1]. The most frequent diagnoses were nodular formations/goiter and drug-induced thyroiditis [1]. Multivariate analysis revealed that end-stage renal disease (ESRD) is a significant risk factor for the development of thyroid diseases during tirzepatide therapy (OR = 2.94) [1]. These findings emphasize the need to monitor thyroid function in patients receiving such drugs, especially in the presence of concomitant risk factors.
Comprehensive Approach and Monitoring in Hypothyroidism Therapy
Successful treatment of hypothyroidism requires not only adequate hormone replacement therapy, but also a comprehensive approach that includes regular monitoring, consideration of comorbid conditions, and individualized treatment adjustment. Regular blood tests for TSH and, if necessary, free T4, allow the doctor to timely adjust the levothyroxine dosage and maintain optimal hormonal balance.
It is also important to consider that hypothyroidism can coexist with other conditions requiring attention. For example, patients with chronic kidney disease (CKD) may experience complications with anemia that require separate management [5]. Although not directly related to hypothyroidism treatment, this underscores the need for a holistic approach to patient health.
To optimize treatment outcomes, particularly in complex cases such as infertility, the standardization of diagnostic criteria and therapeutic interventions is critical [3]. Patients should actively participate in the treatment process, informing their physician of any changes in well-being or the appearance of new symptoms. Lifestyle factors, including a balanced diet and sufficient physical activity, also play a supportive role in maintaining overall health and well-being.
Sources
- Impact of Tirzepatide Therapy on Thyroid Disease: Understanding Risks and Emerging Insights. Clinical obesity, 2026. https://pubmed.ncbi.nlm.nih.gov/42145153/
- Autoimmune thyroid disease in infertility and assisted reproductive technology: A review. Porto biomedical journal, 2025. https://pubmed.ncbi.nlm.nih.gov/41287632/
- Review of Acetazolamide and Novel Medical Paradigms for Idiopathic Intracranial Hypertension Treatment. Ear, nose, & throat journal, 2025. https://pubmed.ncbi.nlm.nih.gov/40801435/
- Executive Summary of the KDIGO 2026 Clinical Practice Guideline for the Management of Anemia in Chronic Kidney Disease (CKD). Kidney international, 2026. https://pubmed.ncbi.nlm.nih.gov/41485807/
- MANAGEMENT OF ENDOCRINE DISEASE: Thyroid and female infertility: more questions than answers?! European journal of endocrinology, 2021. https://pubmed.ncbi.nlm.nih.gov/33460394/
The information presented in this article is for informational purposes only and should not be used for self-diagnosis or self-treatment. Always consult a qualified physician for a diagnosis and the prescription of appropriate treatment.