I think I'm allergic to my Liothyronine. I tried taking 5 mcg 4 times a day and it seemed to have brought on a coughing fit for the last several weeks. So I have gone back to my tried and true NatureThroid. I still take a T3 before bed and sure enough the coughing starts again. I'm thinking maybe my system doesn't like anything synthetic? Does T3 come in a natural form?