A cartridge for a non-lethal self-protection system is received by a launch platform and has a barrel, a compressed gas vessel movable from a retained position to a released position, a retainer selectively retaining the compressed gas vessel in the retained position, a projectile in front of the compressed gas vessel containing an irritant, a diffuser to spread out gas behind the projectile, a cannula with a sharp tip to pierce the compressed gas vessel in the released position, and an annular seal circumscribing the projectile and extending between the projectile and the housing to retain the projectile in the housing until the compressed gas is released from the compressed gas vessel.