Hypothyroidism in India: 2026 Clinical Overview India faces a substantial hypothyroidism burden, with an estimated 42 million affected individuals, many of whom remain undiagnosed or undertreated. Despite being a condition that is straightforward to screen for and generally simple to manage with levothyroxine, gaps persist across primary care, general medicine, gynaecology, and endocrinology. Patients frequently present with non-specific symptoms—fatigue, weight gain, menstrual irregularities, mood changes, hair loss, constipation, or vague somatic complaints—that are often misattributed to stress, anaemia, or lifestyle factors. This leads to delayed diagnosis and prolonged morbidity. Epidemiology and Aetiology in India Prevalence: Approximately 1 in 10 Indian adults has some form of thyroid dysfunction; hypothyroidism (overt + subclinical) is the most common. Sex distribution: Women are 5–8 times more likely to be affected than men. Practical Summary: TSH & Hypothyroidism Key points from the guidance: Best initial test: TSH is the primary screening and monitoring test for thyroid function. Lab reference ranges (e.g., 0.5–5.0 mIU/L) are not ideal targets for every patient. Diagnostic thresholds Overt hypothyroidism TSH > 10 mIU/L Low free T4 Action: Treat. Subclinical hypothyroidism TSH 4.5–10 mIU/L Normal free T4 Action: Individualized decision based on: Age Symptoms Cardiovascular risk Pregnancy status or trying to conceive TSH targets while on treatment General adults: Aim for 1.0–3.0 mIU/L (many endocrinologists prefer the lower end). Pregnancy (1st trimester): TSH < 2.5 mIU/L (ATA target). Elderly (>65 years): 3.0–5.0 mIU/L acceptable. Avoid aggressive suppression due to increased risk of atrial fibrillation and fractures. Cardiac disease: Aim for upper-normal TSH; avoid TSH suppression. Levothyroxine Dosing Healthy adults: start at 1.6 mcg/kg/day. Elderly or cardiac patients: start at 25 mcg/day and titrate slowly every 6 weeks. Recheck TSH 6–8 weeks after any dose change. Administration: take on an empty stomach 30–60 minutes before breakfast. Coffee reduces absorption by 25–30%. Evening dosing (bedtime, ≥2 hours after dinner) is equally effective and useful for patients taking supplements. Thyroid Management FAQs for Indian Clinics Q: My patient is on 100 mcg levothyroxine but still symptomatic with TSH of 2.5. What should I do? A: Before increasing the dose, reassess absorption. Ask about timing (should be 30–60 min before food), coffee intake (reduces absorption 25–30%), and concurrent supplements (calcium, iron, antacids). If absorption is adequate, consider whether symptoms are non-thyroidal. A small subset of patients feel better with TSH kept lower, around 1.0–1.5 mIU/L; an empirical dose adjustment of 12.5–25 mcg with recheck in 6–8 weeks is reasonable. Q: Should I add T3 (liothyronine) for patients who feel unwell despite optimal TSH? A: Most Indian endocrinologists and current ATA guidelines do not recommend routine T3 addition. Evidence of benefit is inconsistent. If you consider it, only in persistent symptoms despite optimal TSH, and refer to an endocrinologist. Combination therapy has a narrow therapeutic window and requires monitoring for cardiac effects. Q: Patient is pregnant. When should I start treatment and what TSH target should I aim for? A: In pregnancy, treat if TSH > 2.5 mIU/L in the 1st trimester, or > 3 mIU/L in 2nd/3rd. Start levothyroxine immediately if TSH > 10 or if hypothyroid on presentation. Increase pre-conception levothyroxine dose by 25–30% as soon as pregnancy is confirmed. Monitor TSH every 4 weeks in 1st trimester, then every 4–8 weeks. Aim for TSH < 2.5 mIU/L throughout. Q: Patient has TSH of 7 and is asymptomatic. Should I treat? A: This is subclinical hypothyroidism. Treatment is strongly recommended if TSH > 10, in pregnancy or planning conception, and in young symptomatic patients. For asymptomatic adults with TSH 4.5–10, the decision is individualised. Treat if: positive TPO antibodies (higher progression risk), age < 65, cardiovascular risk factors, or strong patient preference after discussion. For elderly patients, watchful waiting with 6-monthly monitoring is acceptable. Q: Should I check TPO antibodies in all patients? A: Not mandatory in all, but useful in subclinical hypothyroidism (positive TPO increases annual progression risk to overt hypothyroidism), first-trimester pregnancy (TPO positivity with normal TSH warrants closer monitoring), and when goitre is present. Elevated TPO supports autoimmune (Hashimoto’s) aetiology. Q: Can I switch brands of levothyroxine? A: Levothyroxine has a narrow therapeutic index. Brand substitution can cause small but clinically significant changes in bioavailability. If switching brands is unavoidable, recheck TSH in 6–8 weeks and counsel patients to report symptoms. Advise patients not to switch brands on their own. When to Refer to an Endocrinologist TSH not normalising despite adequate doses (consider malabsorption, poor compliance, drug interactions). Persistent symptoms despite optimised levothyroxine therapy. Central hypothyroidism suspected (low TSH + low fT4 — pituitary or hypothalamic aetiology). Children, neonates, or complex pregnancy cases. Goitre with compressive symptoms or suspicious nodules (refer to endocrine surgery or endocrinology).