I have been taking it for years. I take 50 micrograms/day.
One thing that will render it useless is to not take it on an empty stomach. The directions call for a minimum of one hour before breakfast---that did not work for me. Now I take it about 3 AM at piss call and all has been good for years.
"A pessimist sees the difficulty in every opportunity, an optimist sees the opportunity in every difficulty” ---Sir Winston Churchill
"Political extremism involves two prime ingredients: an excessively simple diagnosis of the world's ills, and a conviction that there are identifiable villains back of it all." ---John W. Gardner
“You can’t go back and change the beginning, but you can start where you are and change the ending.” ---C. S. Lewis