Levothyroxine, also L-thyroxine or T4, is a synthetic way of the thyroid hormone thyroxine, which is normally secreted by thefollicular cells of the thyroid gland. It is also old to use thyroid hormone deficiency, and off to foil the recurrence of thyroid cancer. Like its naturally secreted counterpart, levothyroxine is chemically in the chiral L-form. The mutual sedative dextrothyroxine (D-thyroxine) was habituated to in the quondam as a treatment after hypercholesterolemia (happy cholesterol levels) but was withdrawn apposite to cardiac side-effects. 
History 
Thyroxine was first cloistered in straightforward appearance in 1914 at the Mayo Clinic by Edward Calvin Kendall from extracts of hog thyroid glands.[3 -  The hormone was synthesised in 1927 by way of British chemists Charles Robert Harington and George Barger. 
Medical uses 
Levothyroxine is typically hardened to premium hypothyroidism.[4 -  It may also be utilized to action towards goiter via its gift to downgrade thyroid-stimulating hormone (TSH), a hormone that is considered goiter-inducing.[5 - [6 -  In 1992, President George H.W. Bush told telly host Larry Monarch that he had been prescribed levothyroxine as instances partly of a treatment regimen in behalf of Graves' condition; the swap was transmit busy to satellite dish owners tracking and recording backhaul channels.[7 -  
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