Despite the fact that it would likely be cheaper, powder form internals aren't an attractive proposition for me. As far as I can see no major pharmaceutical company will sell you the powder form straight-up. The people who get powder tend to do so through contacts made over the internet. I think the potential for being ripped off is high, especially with something like male pattern baldness treatments which take a long time to see effects from.
In addition to this, perfectly seriously, my head quite often smells of skunk, from hurried applications of spironolactone after minoxidil or vice versa. That's hard enough to explain to my dear old mum as it is, but if I started fiddling with strange powders as well, I think she'd probably flip her lid.