Euthyroid
A term meaning the thyroid is functioning normally - producing the right amount of hormone.
Euthyroid simply means the thyroid gland is working normally. Thyroid hormone levels - and usually TSH - are within the laboratory's reference range, and the gland is neither over- nor under-active.
The word comes from the Greek 'eu' meaning good or normal. The opposite states are hyperthyroid (too much hormone) and hypothyroid (too little).
Being euthyroid is the aim of thyroid treatment. When levothyroxine is prescribed for hypothyroidism, for example, the dose is adjusted until TSH and free T4 sit within the reference range - a euthyroid state.
It is worth noting that some people continue to feel unwell even when blood tests show a euthyroid picture. This is an area of ongoing research and a good reason to keep an open conversation with your clinician about your symptoms.
Related terms
ThyroidTools is an independent, patient-led project - not a charity, not a medical service, and not affiliated with any healthcare organisation or clinical body. We're not your doctor. We're the friend who helps you get more from seeing one. Nothing here is medical advice; always speak to a qualified clinician about your own situation.