Millions of people have thyroid glands that don’t make enough thyroid hormone to meet their body’s needs. Hypothyroidism (underactive thyroid) is the most common reason some people need thyroid hormone replacement. Today, there are modern, synthetic (laboratory-made) medications approved by the FDA.
Read more at: http://www.fda.gov/consumers/consumer-updates/older-therapies-arent-necessarily-better-thyroid-hormone-replacement
