Considering that a reasonable number of high schoolers in my day (late 90s, early 2000s) took creatine or even steroids without actually competing in a sport, I would think that the statistical significance would continue to amateur road racers.
The piece is that there is always an arbitrary line we create internally and which can keep inching. I joke with a few friends who are doctors about what I should get myself on to run like I’m 20 again and the recurring joke answer for a while now has been consistent with our lifetime of jokes about being alpha or beta and it’s the Low-T, TRT, Ryan Hall thing. One guy continues to chime in, “have you not heard of adderall?”
In small sample size of humans I know, there was also plenty of adderall use at the college level and beyond to be able to hang—either in the classroom, the office, or at a party.
I drink coffee, take B and D vitamins, and that’s about it, but compared to some this would cross a line (it would also matter volume and mode and timing of ingestion I would think).