Use of liothyronine (T3) in hypothyroidism: Joint British Thyroid Association/Society for endocrinology consensus statement

Establish a diagnosis of overt hypothyroidism; patients with persistent symptoms on thyroid hormone replacement but no clear biochemical evidence of overt hypothyroidism should first have a trial without thyroid hormone replacement.

In established overt hypothyroidism, optimise LT4 dose aiming for TSH 0.3-2.0 mU/L for 3 to 6 months before assessing therapeutic response.

In some patients, serum TSH below reference range (e.g. 0.1-0.3 mU/L) but not fully suppressed may be acceptable long term.

For some patients with confirmed overt hypothyroidism and persistent symptoms despite adequate LT4 treatment, with other comorbidities excluded, a trial of liothyronine/levothyroxine combined therapy may be warranted.

The decision to start liothyronine should be shared between patient and clinician.

Clinicians should not feel obliged to start liothyronine or continue liothyronine provided by others or accessed without medical advice if they judge this not in the patient's best interest.