Sir, don't dare dream of doubling synthroid (T4), you are going to have a heart attack. I only doubled a T3 (cytomel). Did you ever get your T3 tested or just your TSH? What age did you get it? Hypos will always have slower progress than people with normal metabolisms, but if you have been on meds for a while, the difference shouldn't be drastic. We don't absorb the meds well if we are vitamin D or selenium deficient though. I've had it for years but only recently got diagnosed and started treatment, so I hope to be normal by mid 2013.
i would never fukk around w those kinda meds like that. i take 1x137mcg tablet of synthroid every morning as prescribed and that's it. i was first diagnosed when i turned 26 (i'm 32 now). i have my bloodwork tested every few months to make sure the dosage is sufficient for whatever they say my thyroid levels are. i don't know exactly what they screen but next time they send me a slip for my bloodwork i will check. i'm pretty sure i remember seeing "T3" on the last slip though. i supplement with vitamin d (not because of thyroid, just one of the vitamins i take). my dr says my current dosage seems to be working well for me but who knows. i have to believe i'd be progressing better if i didn't need the meds.