The purpose of this study is to evaluate whether taking thyroid hormone medication with beverages other than water, decreases absorption of the medication by the intestine. Specifically we are interested in whether coffee, coffee with milk, or black tea affects how thyroid medication is absorbed by the body. Previous studies have suggested that taking thyroid hormone with coffee may interfere with the ability to absorb thyroid medicine. Given that many patients take their thyroid medicine with beverages other than water, and specifically with coffee or tea, understanding whether and how much coffee or tea may decrease thyroid hormone absorption is important for clinical practice.