I was on Alan's high school team and the idea that he ever doped is just hilarious and stupid. In middle school he was known as a great runner (and unlike some middle schools that have real track teams or can join their accompanying high school team, we didn't have that).
Then in high school when he joined the team and actually started training he progressed naturally over those years and ended up arguably the greatest high school runner ever, no doubt our high school training worked very well for him.
Now, look what he did as a professional. Everyone realizes he didn't reach his potential. When he was healthy he was amazing (2004, 2005, 10k in 2006 before injury, 2007). When he was injured like at Michigan and post-2007 he ran poorly. Because of all these injuries we all know he didn't reach his potential, he was just starting to hit his peak after years of steady progression (and a couple injuries) when everything went to hell and the endless injuries started. If he had ever been doping there wouldn't have been a natural progression, instead he probably would've suddenly busted out a 3:27 1500 in 2005 or something and we'd be wondering where that came from.
Here is here 1500/Mile in years:
Freshman HS: 4:23 - I think, first year training, but not training year round
Sophomore HS: 4:06 mile - First year training year-round
Junior HS: 4:03 mile (slight injury at end of season so Raczko ended it early)
Senior HS: 3:59i, 3:53 (trained his ass off in XC to try to beat Ritz)
2002: Injured first half of track season so wasn't as good as previous year
2003: 3:58ish, not sure what happened here, but ended year with appendectomy
2004: 3:32 1500 - back on his game, natural progression from 3:53 3 years ago
2005: I think he still ran 3:32, but improved other events like 800, 2 mile AR, 5k
2006: 27:34 10k, then got injured
2007: 3:30, 3:46, natural progression from having run 3:32 3 years earlier
2008: over-trained?
2009 and beyond: mostly injured.
No where in there is there anything but natural progression and come backs from injuries until he could no longer come back from them.