Triiodothyronine

A T3 thyroid hormone normally synthesized and secreted by the thyroid gland in much smaller quantities than thyroxine (T4). Most T3 is derived from peripheral monodeiodination of T4 at the 5' position of the outer ring of the iodothyronine nucleus. The hormone finally delivered and used by the tissues is mainly T3. This definition is taken from the National Library of Medicine's MeSH (Medical Subject Headings) 2026 release, which is the standard vocabulary used to index PubMed and most medical literature.

Yes. Triiodothyronine is also referred to as T3 Thyroid Hormone, Thyroid Hormone, T3, Cytomel, Liothyronine in different clinical, research and patient-facing contexts. The MeSH descriptor groups all of these synonyms under a single canonical concept so research and records stay consistent.

Triiodothyronine falls under the broader medical category "Chemicals and Drugs" in the MeSH hierarchy (tree numbers: D06.472.931.740.385, D12.125.072.050.767.741.894). Browsing the related concepts on this page takes you to neighbouring topics in the same branch of medicine.

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