When did Manny start taking it?
It's hard to know exactly. There are no spikes in Manny's career that would indicate anything suspicious. He was always a tremendous hitter.
It was leaked that both Manny and David Ortiz tested positive in 2003 along with 101 other players, although "officially" that list was not corroborated.
At the very least we know he was on something in 2003.
But the way MLB handled that whole PED situation was horrendous.
First being that those 2003 survey test results were supposed to be sealed. Testing was to be random. A refusal or failure to take a test would automatically be counted as a positive test (a bit unfair depending on circumstances). And I thought the testing was supposed to be anonymous, although I can't seem to confirm that part of it. The point being that due to the CBA if 5% of players or more tested positive in 2003, it would kickstart random drug testing in 2004 and going forward. The 103 players that were leaked amount to roughly 14% of players (if you assume just the 750 active on MLB rosters at a given time). But we know that it was way more than 14% of players using PEDs in that era. So you have a big, BIG chunk of guys who tested positive but managed to avoid the heat. This is why you have to believe some agenda or politics was involved because a lot of guys were protected.