This one antioxidant is ULTRA important for your thyroid function Glutathione is our body's master antioxidant meaning it's the most important and abundant one. As it relates to the thyroid, think GnIH induced mitochondrial dysfunction lead to oxidative stress and apoptosis in thyroid follicular cells, causing hypothyroidism ScienceDirect Raised plasma glutathione S transferase values in hyperthyroidism and in hypothyroid patients receiving thyroxine replacement The BMJ Frontiers Selenium and thyroid diseases