29 In the index

Levothyroxine T4

The FDA-approved synthetic thyroid hormone, the standard treatment for an underactive thyroid and one of the most commonly prescribed medications anywhere. Decades of use firmly confirm it works safely when dosed correctly for each person.

Also known as Synthroid, T4, thyroxine, thyroxin, L Thyroxin beta, L Thyrox, L Thyroxine Roche, L Thyroxin Henning, Levothyroxin Delalande, RefChem:5946

Effects Hormonal Lose fat

Routes Oral

Legal status Prescription drug

WADA Not listed

3D Molecular Structure of C₁₅H₁₁I₄NO₄

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Chemistry

Formula: C15H11I4NO4
Molar mass: 776.87
CAS: 51-48-9
PubChem CID: 5819
IUPAC name: (2S)-2-amino-3-[4-(4-hydroxy-3,5-diiodophenoxy)-3,5-diiodophenyl]propanoic acid
InChIKey: XUIIKFGFIJCVMT-LBPRGKRZSA-N

Reported dosing

Approved label

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

Typical dose 1.6 mcg/kg/day (typically 75-150 mcg/day)

Reported range 25-300 mcg/day, titrated to bloodwork

Route Oral

Frequency Once daily

Duration Chronic/ongoing (as prescribed)

FDA-approved thyroid hormone replacement (Synthroid); dosing is individualized and monitored via TSH bloodwork, not appropriate for use in people with normal thyroid function.

Where this comes from FDA prescribing information

These figures are recorded for reference and are not a recommendation. Dosing is a decision for you and a clinician.