A powder inhaler having reservoirs containing a dose of powder and formed on a flexible blister strip having a base layer with cavities and a closure layer. The base layer containing empty blisters rolls up around a first rotary receiver element, and the closure layer peeled off the base layer rolls up around a second rotary receiver element that has a first portion forming a peeling wheel and a second portion forming a tensioner. The tensioner is capable of turning in a first direction of rotation and includes a fastener element for the leading end of the closure layer. The tensioner turns with the peeling wheel in the first direction to roll up the closure layer at each actuation of the device and turns relative to the peeling wheel in the first direction of rotation to tension the closure layer after the blister strip has been assembled in the body.
