Synthroid (levothyroxine sodium) is a synthetic compound identical to T4 (levothyroxine) produced by the human thyroid gland used to treat hypothyroidism due to many causes (for example: and other causes). Synthroid is also used for pituitary TSH suppression. Synthroid is available in generic form. What Are Side Effects of Synthroid? Synthroid is brand name for levothyroxine, which is commonly used to treat hypothyroidism (low thyroid levels). Synthroid and levothyroxine are human-made thyroxine (T4) hormones. If you've been prescribed thyroid hormone replacement, you've likely encountered the brand name vs generic debate. Synthroid is a brand-name version of levothyroxine — the most commonly prescribed thyroid hormone medication in the US. Synthroid is the brand-name form of levothyroxine. They’re both prescribed for certain thyroid conditions, including hypothyroidism caused by Hashimoto disease (also called Hashimoto thyroiditis). SYNTHROID® (levothyroxine sodium) tablets, for oral use is a prescription, man-made thyroid hormone that is used to treat a condition called hypothyroidism in adults and children, including infants. Unithroid and Synthroid are brand names for the drug levothyroxine. Both medications contain the same active ingredient, levothyroxine, but some of their inactive ingredients are different. Popular brand names for levothyroxine (T4) include but are not limited to Synthroid®, Levoxyl®, Unithroid ®, Tirosint® in the United States and Euthyrox® and Eltroxin® in Europe. Levoxyl and Synthroid are brand names for the drug levothyroxine. Both medications contain the same active ingredient, levothyroxine, but they contain different inactive ingredients. SYNTHROID® (levothyroxine sodium) tablets, for oral use is a prescription, man-made thyroid hormone that is used to treat a condition called hypothyroidism in adults and children, including infants. Levothyroxine, also known as L-thyroxine, is a synthetic form of the thyroid hormone thyroxine (T 4). [4][7] It is used to treat thyroid hormone deficiency (hypothyroidism), including a severe form known as myxedema coma. [4] It may also be used to treat and prevent certain types of thyroid tumors. [4] It is not indicated for weight loss. [4].