Levothyroxine (Synthroid) Supplement Interactions Supplements To Avoid While Taking Thyroid Hormones ConsumerLab.com Ferroptosis in thyroid cancer: Potential mechanisms, effective therapeutic targets and predictive biomarker ScienceDirect Glutathione is the body's primary internal antioxidant, made using the amino acid cysteine, and it helps protect cells from oxidative stress. Beyond detoxification, research shows glutathione is involved in thyroid hormone metabolism, Levothyroxine (Synthroid, Tirosint, Levoxyl) is a medication for treating hypothyroidism (underactive thyroid), a condition that is more common in people with Down syndrome. Health care providers usually recommend taking levothyroxine with water