An Inserter for inserting a needle through the skin of a user that includes: a needle holder block deployed in the inserter housing, the needle holder block displaceable between a cocked position and an insertion position such that when in the cocked position the needle holder block is biased toward the insertion position a biasing element configured to bias the needle holder block toward the insertion position when the needle holder block is in the cocked position and a manually operated mechanical controller for controlling displacement of the needle holder block so as to control at least a speed at which the needle holder block is displaced between the cocked position and the insertion position. Also described is an inserter having a mechanism for varying the biasing force of the biasing element so as to affect at least a speed at which said needle holder block is displaced.
