An injection device including a barrel having an internal medication reservoir, a plunger received within the barrel and axially movable relative thereto, a grip fixed to the plunger and axially overlapping a portion of the barrel, the grip configured to be locked relative to the barrel to prevent axial movement therebetween, a needle attached to one end of the barrel, and a needle guard configured to retract into the barrel in response to force against an injection site to unlock the grip from the barrel to permit relative axial movement therebetween.
