When I was diagnosed with Underactive Thyroid it was found I could only take Eltroxin (Goldshield). After the change over with Goldshield etc. my prescriptions have always stated MERCURY, which I understood was the same formula as Eltroxin. Now my prescription has changed to read AMCo. I am assuming this is the same company, but, if so have the ingredients changed. The Doctors and Chemist are most unhelpful. Can anybody please enlighten me?