Generic Synthroid is used for treating low thyroid activity and treating or suppressing different types of goiters. It is also used with surgery and other medicines for managing certain types of thyroid cancer. More info »
Regarding the effect: I do notice an increase in bloodflow and a better
stamina using the pills (I use 50mg). A side-effect I have noticed is that
my nose clogs up so I seem like I have a cold for an hour or so after taking
one pill. No other side-effects than that.