I originally stopped using T3 as my supplier stopped selling it. I had a think then and as I have no idea what my thyroid status is and whether or not I could benefit from T3 supplement I am not happy to take it without someone monitoring it for effects.
Interestingly I was on T3 last year and was still taking it right up until I collapsed with multiple organ failure followed by a cardiac arrest and coma. I wasn't being monitored because I couldn't find an NHS doctor to do this and until I do then I wouldn't touch T3 with a barge pole