What's in a name?

Phentirmene, Phenylethylamine or Phentermine 37.5? How do you know the difference? and how will they affect you? In short, my internet searching tells me that Phenylethylamine can stimulate the central nervous system and is thought to promote pleasure. It can be combined with other substances (such as Phentirmene) to make them more effective.
On the other hand, Rx Phentermine is an appetite suppressant with some fairly risky side effects. If you are looking at self-medicating for dieting - make sure you find out a little about what you are introducing into your body.