The 30-year-old pointed at the history of drug use in football as proof that it happens, and also hinted that the problem is biggest in Italian football.
"What about drug use in football? There is a history of it. A number of professionals were reportedly caught up in a performance-enhancing drug scandal (Jaap Stam, Edgar Davids, ...) as well as a number who allegedly delved into recreational drug use (Maradona, Mutu, Bosnich, ...). It's there; all you have to do is look," wrote Barton.
"Have you ever wondered how some of the top Italian league players have played at such a high level for so long, this is a bunch of players at the top who are (or were, when playing) fast heading towards 40 and running around like someone in there early 30's, and playing up to 80 games each season.
"We know some top European clubs used or still use 'vitamin' injections – and there are organizations (like the USADA) who have been digging into it for over 10 years, to little avail, suggesting that there's sophisticated cloaking of banned substances in 'vitamin' supplements, they just can't get the evidence."
Barton also questioned the level of testing for banned substances in the game, claiming that it is not stringent enough.
"My personal experience of drugs tests, as a professional athlete, is that they have only ever taken a urine sample from me," he added.
"I have never had blood taken during my whole career! I have never had a hair sample taken. I didn't know of this procedure until writing this piece and forgive me if I am wrong but doesn't the hair hold on to the use of substances for a lot longer than urine or blood.
"For instance in recreational drugs usage, sometimes the said drug can be flushed out of one's system within days, where as the hair follicles hold on to proof of the same drug usage for up to 3 months. Shouldn't hair be tested? I mean if your clean you're clean, right?"
Barton previously expressed his surprise at Nike's decision to stand by Lance Armstrong.