Euthyrox 100mcg is a prescription medication containing levothyroxine sodium, manufactured by Merck. This medication is used to treat thyroid hormone deficiency and comes in a pack of 100 tablets. Each tablet contains 100 micrograms of the active ingredient levothyroxine sodium. Euthyrox is used as thyroid hormone replacement therapy in conditions where the thyroid gland does not produce enough natural hormones (hypothyroidism). The medication should be taken exactly as prescribed by your healthcare provider, typically once daily on an empty stomach. Regular monitoring of thyroid levels through blood tests may be required to ensure proper dosing. This is a prescription-only medication that should be used under medical supervision.