That's insane. It's not an amphetamine. But taking too much can not only give you a massive heart attack, it can blind you first.
Taking levothyroxine when it’s not necessary simply reduces the amount the thyroid gland produces. That’s why taking it when not needed is always something of of an overdose if being used as kind of subtle amphetamine. Some think they can balance between a long term general mild stimulant and endangering heart stress and and high metabolism. Theoretically possible, but not really practical.
People who are hypothyroid are even hyperthyroid intuitively understand.