Desoxymethamphetamine doesn't make sense. I assume you mean desoxyephedrine. This is simply another (less stigmatized) way of saying methamphetamine. It was, and now called levamethamfetamine (LOL, sic), still is available otc. Problem is it's the weak l isomer of meth and while it does do something it is nowhere near as good as propylhexadrine. But I've seen people do the shit and love it. Why I haven't a clue.The ones I used to buy(haha) in the 70s & 80s on the label it said active ingredient 50mg desoxymethamphetamine HCL. It don't get no more pure than that. Those haven't been on the market since the early 80s. Used to do a simple extraction with muriatic acid and rubbing alcohol then evaporate in a Pyrex pie plate. Not too bad
I wouldn't go the caffeine pill route. Once I ate 8 caffeine pills at once and it basically burned a hole in my stomach lining and twisted my world into a jittery unfun mess for a couple hours. I was bedridden the whole next day with stomach pains.