Pretty uncomfortable? To much T3 potentiates a hyperthyroid crisis.
VETS on here and other places, have used T3 and/or T4 for years without any negative effects. Does that mean that it is a casual thing, like changing ones diet? or, "pretty uncomfortable," NO! It is on the level of insulin. And, not something that someone should add to their first cycle. It is definitely responsible to warn a person whose first cycle consists of Proviron and "what should I add to Proviron?" and irresponsible to to point of incredulous to say "uncomfortable." Can it be used safely? Yes, by those who have the knowledge and ability to make safety a priority.