T3 (liothyronine)
Hormones · Active thyroid hormone
Tier B
What this is
Often sought by patients who feel unwell on T4 monotherapy despite normal TSH. AACE/ATA 2014 guidelines acknowledge T3 combination therapy as reasonable. Abuse for weight loss is dangerous — cardiac and bone consequences. Short half-life typically requires divided dosing.
Mechanism
Biologically active thyroid hormone; binds thyroid hormone receptors (TRα, TRβ); upregulates metabolic rate, lipolysis, protein turnover; shorter half-life (~1 day) than T4
Dose & route
Clinical: 5-25 mcg/day; combo therapy with T4
Citations
- https://pubmed.ncbi.nlm.nih.gov/25266247/
- https://pubmed.ncbi.nlm.nih.gov/17283286/
- https://pmc.ncbi.nlm.nih.gov/articles/PMC6031714/
Links go to the source. If a link is dead or you want something re-checked, let me know.
This is an independent synthesis of published research by a non-clinician. Scores are opinions supported by citations, not prescriptions. See the full disclaimer and methodology for how this score was produced and what it does and doesn't mean.