I began treatment for hypothyroidism with a prescription for Armour Thyroid. As I neared the end of the first 30 days I was informed by my health plan that Armour was not in their formulary so they would not pay for it. I then switched to levothyroxine, which is on the plan's formulary and within 3-4 days I began to experience severe muscle and joint pain to the point I was losing sleep, couldn't go to the gym, and was unable to work on my wife's "Honey Do" list. I discontinued the drug after 2 weeks...and after one week with no treatment have gone back to Armour (I'm paying for it myself). I'll let you know if being back on Armour helps me feel better.