My thyroid was removed in 2011. Since then I am on thyroxin 125 microgram, 100 ug from Actavis and 25 ug from Wockhardt. Have always been stable as a rock with right blood levels of T3 and T4. 2 weeks ago I received TEVA 25 ug instead of the usual brand and after 2 days I started to feel sick as a dog. Sweating, hot flashes, abnormally anxious, hyper, headache. Immediately stopped the TEVA, luckily I still had some of the old prescription. Now I have a very hard time to obtain Actavis and Wockhardt pills again through the NHS. Even with a prescription it is impossible to find these brands at several pharmacies around. What is going on in that industry? If so many people are on thyroxin, should there not be a relatively good and secured availability of brands? Certainly, if stability of T3/T4 levels in your blood are so important, why playing around with different brands all the time? Despite the medical tests I do not buy the message that all the brands are giving identical results for everybody. (Un)fortunately human beings are very complex and they come with a lot of variation between individuals. Hence, it would be advisable that once someone is stable, every change in medication should be avoided whenever possible. That is what is required to optimise patients well being and maximise his or her potentials.