About a year ago I was diagnosed with low testosterone. I guess it's the current 'in thing' these days for docs to look for in men over 40. I didn't have any noticeable sexual dysfunction, but I was noticing abnormal fatigue and so on. I probably didn't need it, and my doc went all out, bypassing the creams, and giving me a prescription for Delatestryl, an injectable pure testosterone.
So, as a distance runner, I obviously considered the possibility that this prescription might have the side-effect of being a PED, although my admittedly limited knowledge of this stuff would suggest that it would clearly enhance any activity requiring explosive power and raw strength, but I didn't (and still do not) see the connection to distance running.
I did some research, and tried a reasonable dosing schedule that was a fair amount more than required for low-T, but not at the level of someone looking to bulk up. This trial lasted about 10 weeks.
Results: I gained a little over 10lbs, going from about 135lbs to 145-ish (I'm 5'10"), although I touched no weights. My biceps went from a typical distance runner's size of 12.5" to 13.25" (again, zero weights, push-ups, or anything). My RHR increased (a known side-effect of testosterone). My running got worse; more than the expected amount from the weight gain. I just got out of breath at the strangest times.
I am not a terrible runner for my age (44), still able to run 5k in low 17s, but I expected something positive to happen regarding my fitness level, since I hear of elites using this as a PED. It would not be worth the risk without some sort of gain.
When I ceased using testosterone, my fitness slowly came back, as my testosterone levels slowly decreased. Why did testosterone use actually cause negative results with my distance running?