Here is the original FDA letter to VPX regarding White Heat. The chemical they are focusing on is 4-Amino-2-Methylpentane Citrate also known as 1,3-Dimethylbutylamine, DMBA, 2-amino-4-methylpentane, AMP citrate, and 4-methyl-2-pentanamine (according to the FDA letter). Upon further research, it seems like, although the structure of the compound is similar to an amphetamine, the actual mechanism of action of these and similar compounds, such as DMAA, still isn’t fully known. So it was a bit inaccurate of me to call it an “amphetamine analogue” since they might not work in a similar manner.

I don't know about that drink of theirs and have the same doubts as you but here in nl some companies produce ever-changing molecules that are close to the real stuff but different enough that the specific compound isn't banned yet. The one I know of only sells to other European countries.