Hypothyroidism Treatment Seoul — underactive thyroid specialist in English.
Hypothyroidism diagnosis and management at Apgujeong Hana Clinic, Apgujeong, Gangnam. Board-certified endocrinologist — TSH testing, levothyroxine management, Hashimoto's evaluation and long-term thyroid monitoring in English.
Hypothyroidism — the most missed diagnosis in adults.
Hypothyroidism occurs when the thyroid gland produces insufficient thyroid hormone — primarily thyroxine (T4) — to meet the body's metabolic needs. The thyroid controls the rate at which virtually every cell in the body operates. When production falls short, the effects are wide-ranging, often gradual and frequently attributed to other causes such as stress, ageing or depression.
Hypothyroidism is one of the most common hormonal conditions worldwide — affecting an estimated 5% of the adult population, with significantly higher rates in women, particularly over the age of 40. The most common cause in adults is Hashimoto's thyroiditis — an autoimmune condition where the immune system slowly destroys thyroid tissue over months or years. Because the decline in thyroid function is gradual, symptoms develop slowly and are often normalised by patients for years before a diagnosis is made.
At Apgujeong Hana Clinic, our board-certified endocrinologist Dr. Shin Hyun-won diagnoses and manages hypothyroidism with a full thyroid panel — not just a TSH — ensuring that subclinical hypothyroidism, autoimmune thyroid disease and T3/T4 conversion problems are not missed. Levothyroxine is available in Korea and dose optimisation is carried out with regular monitoring in English.
Symptoms of hypothyroidism — why they are so easily missed.
Hypothyroidism symptoms are non-specific — they overlap with dozens of other conditions including depression, chronic fatigue syndrome, anaemia and simply "ageing." This is precisely why hypothyroidism is so commonly missed or misattributed for years. If you experience several of the following symptoms — particularly fatigue, weight gain and cold intolerance together — a thyroid blood test is essential.
What your TSH level means — and why the range matters.
TSH (thyroid stimulating hormone) is the most sensitive marker of thyroid function. It is produced by the pituitary gland — when thyroid hormone is low, the pituitary increases TSH to stimulate the thyroid to produce more. A high TSH therefore means the thyroid is underperforming. However, the standard "normal range" for TSH varies between labs and is broader than many specialists would consider optimal for patient wellbeing.
| TSH Level | Category | Free T4 | What It Means |
|---|---|---|---|
| 0.4 – 4.0 mIU/L | Normal Range | Normal | Thyroid functioning within standard range — symptoms assessed alongside results |
| 4.0 – 10.0 mIU/L | Subclinical Hypothyroidism | Normal | Mildly elevated TSH — treatment decision based on symptoms, antibodies and risk factors |
| Above 10.0 mIU/L | Overt Hypothyroidism | Low | Clear hypothyroidism — levothyroxine treatment recommended |
| Above 10 + antibodies | Hashimoto's Hypothyroidism | Low or Normal | Autoimmune thyroid disease confirmed — treatment and progression monitoring |
| Below 0.4 mIU/L | Suppressed TSH | High | Hyperthyroidism or over-treatment with levothyroxine — dose reduction needed |
What causes hypothyroidism — and who is most at risk.
Understanding the cause of your hypothyroidism is important — it affects how the condition is monitored and whether additional testing (such as antibody panels or ultrasound) is needed. The most common cause is autoimmune in origin.
How we treat hypothyroidism at Apgujeong Hana Clinic.
Hypothyroidism treatment is straightforward in principle — replace the thyroid hormone the gland cannot produce adequately. In practice, optimal management requires careful dose selection, individualised TSH targeting and symptom-based monitoring to ensure each patient feels well — not just that their blood results fall within a reference range.
Your hypothyroidism consultation, step by step.
Your questions answered.
More questions about hypothyroidism? WhatsApp our English-friendly team at Apgujeong Hana Clinic.
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Get your thyroid tested at Apgujeong Hana Clinic.
Hypothyroidism diagnosis and management in English — Apgujeong Hana Clinic, Gangnam Seoul. Levothyroxine available. Same-week appointments.