Don't expect miracles. You may not look as awesome as the guy in he product picture, but if you are a little too large for a suit jacket, this will probably do the trick. Specifically, if you stomach is too large for a jacket this will help.

I had several jackets that I nearly ate my way out of. I could button them, but I wouldn't wear them.  This shirt allowed me to wear them comfortably. It's definitely a better option than having suits constantly tweaked.