The thyroid gland produces hormones - thyroxine (T4) and triiodothyronine (T3) - that regulate baseline metabolic rate, body temperature, cardiovascular function, and systemic protein synthesis. When thyroid hormone production shifts out of balance, the resulting symptoms can affect virtually every organ system in the body.
Hypothyroidism (underactive thyroid) occurs when the thyroid produces insufficient T4 and T3. This reduction slows metabolic processes, frequently resulting in persistent fatigue, unexplained weight gain despite reduced appetite, cold intolerance, dry skin and hair, constipation, brain fog, and bradycardia (slow heart rate). These signs are commonly mistaken for normal aging or general stress, delaying diagnosis.
Hyperthyroidism (overactive thyroid) involves overproduction of thyroid hormones, which accelerates metabolic rate. Symptoms include unintended weight loss despite normal or increased food intake, tachycardia and palpitations, atrial fibrillation risk, fine tremors in the hands, heat intolerance, and increased anxiety or irritability. Graves' disease - an autoimmune condition - is the most common cause.
Diagnosis begins with a simple TSH (thyroid-stimulating hormone) blood test. An elevated TSH suggests hypothyroidism; a suppressed TSH suggests hyperthyroidism. Free T4 and T3 levels, along with thyroid antibody testing, provide a more complete clinical picture. The American Thyroid Association recommends TSH testing every 5 years for adults over 35, and more frequently for those with symptoms or risk factors.
Both conditions are highly treatable. Hypothyroidism is typically managed with daily levothyroxine - a synthetic T4 - with dose titration based on symptom response and laboratory values. Hyperthyroidism options include antithyroid medications, radioactive iodine therapy, or surgical thyroidectomy, depending on cause and severity. Early detection is key to preventing long-term complications.
Medical Disclaimer: The information in this article is for educational purposes only and should not be construed as medical advice. Always consult a qualified healthcare professional regarding any hormonal condition or treatment plan.
Dr. Rohan Iyer
Endocrinologist
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