Hormones & metabolismHormonalICD-10 E03
Hypothyroidism (underactive thyroid)
Also called: Underactive thyroid, Hashimoto's thyroiditis, Myxoedema
The thyroid does not produce enough thyroid hormone, slowing the body's metabolism. It is easily treated with a daily hormone tablet.
Condition-specific references are below. Individual claims and this page have not been clinically reviewed. Read about this content.
Causes
- Hashimoto's autoimmune thyroiditis (most common in iodine-sufficient areas)
- Iodine deficiency (worldwide)
- After thyroid surgery or radioactive iodine
- Medicines (amiodarone, lithium)
- Pituitary disease (rare)
Risk factors
- Female sex
- Age
- Family history
- Other autoimmune diseases
- After pregnancy
Symptoms
- Tiredness
- Weight gain
- Feeling cold
- Constipation
- Dry skin and hair loss
- Low mood
- Heavy periods
- Slow heart rate
Diagnosis — tests and examinations
- High TSH and low free T4
- Thyroid peroxidase antibodies
Treatment
Medicines and medical treatment
- Levothyroxine daily on an empty stomach, dose adjusted to TSH
Self-care, home remedies and lifestyle
- Take the tablet consistently; separate from iron and calcium
- Regular blood tests
Possible complications
- Heart disease from high cholesterol
- Infertility and pregnancy complications
- Myxoedema coma (rare)
Prevention
- Adequate iodine intake
Outlook
Excellent with treatment.
When to see a doctor
See a doctor for persistent tiredness, weight gain and feeling cold.
Sources and further reading
These sources cover this condition. They have not been checked against every statement on this page.
Related conditions
Educational overview, not medical advice. Treatment varies by person and location. Consult a qualified health professional for diagnosis or care. Read our content and model notes and privacy information.