I had extreme fatigue. I was so ill that my gut stopped working and could not digest anything. But my blood tests were fine(only b12 and iron were low but not below the range). Finally i did some thyroid tests and my tsh was 4.7 and T3 and T4 both extremely low.
Started at 65mcg and then at 185mcg for 1.5 months and nothing. No increase in energy, no better digestion ,nothing. Finally i tried 25mcg liothyronine and for the first time after many years i felt alive. Not great, but alive. I lowered the dose to 125mcg levothyroxine and i take now 75mcg liothyronine.
According to most people that's a lot. That's 350mcg. But still i don't have increased heart rate, or hyper symptoms. Just increased energy , better digestion and libido. Still i am not cured because i can't work out. I will say that i am cured if i work out 2 times per day and still have energy.