Hi, I have been on thyroxine for 41 years after going into a myxoedema coma. I have always struggled with stabilising the dose and symptoms but as I have got older it is getting harder to find the right dose. I would just like to get through the day without feeling so exhausted. My GP keeps my t4 high and tsh low And this stabilises my heartbeat. I take vit.d as I was lacking but have found no improvement in my energy levels. Can this be an effect of taking thyroxine for so long?