phentermine (bontril) works for a short period of time only, I've used it but it increases my BP too much.
For what it's worth, a friend just asked me that same question , here is my reply--
Phentermine is the same as Bontril ,
Do Not get anything that says HCL (like Adipex), it's time released crap.
Phentermine and all that family of diet pills is fine if you
use it once. But your body builds a tolerance really fast
so you're wasting your money if you use it for more than a month or two.
Another alternative is Lipodren which has Hoodia & Ephedra ( both
plants suppress your appetite and increases your metabolism, peps you up)
Again, if you take it more than 2 months in a row it becomes less affective
I've tried Bontril but 80% of people who use is gain more wieght than
they started with after they stop taking it.
(that's a medical fact)
And all of the above stop working after a while, they tear down muscle
and they speed up your heart rate, which is not good.
Another one is Clen which is preferred by most BB.
http://www.ag-guys.com/
I suggest
Bioperine Advanced Gingo Biloba,
Alpha Lipoic Acid & Acetyl L-Carnitine
and Biochem Sports Ultimate Fat Metabolizer (Chromium Picolinate)
Take per direction, it has the almost the same boost of energy as
Bontril with none of the side-effects. And you can take it long term
because your body doesn't build up tolerance.
It's worked great for me.
the_short_one , great gams ya got there

and yea, GNC sucks