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Hormones / Thyroid hormones

28 In the index

Liothyronine T3

The FDA-approved synthetic form of the body's more active thyroid hormone, used medically for thyroid problems and off-label, at higher doses, for fat loss because it acts fast. Its medical use is well supported; using it for fat loss carries a real risk of overstimulating the body and breaking down muscle.

Also known as Cytomel, T3, 3,3',5-Triiodo-L-thyronine, triiodothyronine, Liothyronin, 3,5,3'-triiodothyronine, L-Liothyronine, Tresitope, triothyrone

Effects Hormonal Lose fat
Routes Oral
Legal status Prescription drug
WADA Not listed

3D Molecular Structure of C15H12I3NO4

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  • Carbon
  • Hydrogen
  • Iodine
  • Nitrogen
  • Oxygen

Chemistry

Formula
C15H12I3NO4
Molar mass
650.97
CAS
6893-02-3
PubChem CID
5920
IUPAC name
(2S)-2-amino-3-[4-(4-hydroxy-3-iodophenoxy)-3,5-diiodophenyl]propanoic acid
InChIKey
AUYYCJSJGJYCDS-LBPRGKRZSA-N

Reported dosing

User-reported

What has been reported in the literature and by users. This is a record of what is done, not a recommendation.

Typical dose 25 mcg/day
Reported range 5-100 mcg/day depending on indication; off-label bodybuilding fat-loss doses often at the higher end and unsupervised
Route Oral
Frequency 1-2 times daily
Duration Chronic (as prescribed, hypothyroidism) or short cycles (off-label fat-loss use)

FDA-approved fast-acting thyroid hormone (Cytomel); off-label bodybuilding use for fat loss risks thyroid suppression and muscle loss if misused.

Where this comes from FDA prescribing information; off-label user-reported dosing

There is no approved human dosing for this compound. The figures above are what users and vendors report, not what has been established as safe or effective. Treat them as a record of what is done, not as guidance.