I read some post on here regarding 'unexplained' breathlessness. I too have constant breathlessness, which is becoming extremely debilitating. I have been on Levothyroxine for some 35 years and take 150mcg daily. Strangely, I was diagnosed with hypothyroidism only after I suffered a kind of breakdown and severe depression. I was put on antidepressents and am still on tghem. The dicovery of hypothyroidism was coincidental at this time. I have often thought that my severe depression was actually caused by the undiscovered Hypothyroidism itself? The breathlessness, constant tiredness and air hunger has really only become a big issue for the last couple of years. Until now, I have acctually put that down to spinal surgery 3 years ago, which was not a success, but am not at all sure now. Needless to say the medical profession are not in the slightest bit helpful, the best I have been offered following an Xray and spirometry tests (normal) is physiotherapy, teaching me to breathe correctly! Obviously my GP is not interested in T4 or T3. There have been several links to blood test establishments via post on here, but I am wondering if there are some that can be recommended? And which type I might be best to go for? Any views and advice would be hugely appreciated.