The 21-year-old admitted a Football Association charge after an out-of-competition test in February showed traces of the banned anabolic steroid.
Kinsella attended an Independent Regulatory Commission hearing to give his version of events and can still choose to appeal his suspension.
The two-year ban will be backdated to the date he gave his sample - February 5 - ruling him out of the game until February 4, 2015.
Kinsella, a former youth-team player at Everton, spent time on loan at Telford last season and is yet to make his senior Fleetwood debut.
Steve Curwood, Fleetwood's chief executive, said: "Fleetwood Town will make a statement about Gerard Kinsella in the fullness of time.
"The verdict has only recently been made by The FA and we have no further comment at this stage."