[jerf]

Well... we're generally used to "adulterants" referring to inactive or even potentially (purely) harmful ingredients being added to things to make them cheaper. However, note that "adulterating" your sexual potency supplement with Viagra means that it will, you know... work. Same with putting steroids in your workout supplement... it makes it work, better than the competition that doesn't do it.

There are all kinds of other problems with that, of course. I'm not saying it's a good idea. But in terms of "why would people buy these?", well, I'd suggest part of the reason is that people want to lose weight, be sexually potent, or get swole, and these "adulterated" supplements actually work. Just at a cost you may not have realized you were paying, or intended to pay.