A wearable injector comprising: an injector housing comprising a base surface and an opposing top surface, the base surface being configured to contact a skin surface of a user and having an opening therein, and the top surface defining an opening therethrough; an injection needle mounted within the injector housing and translatable along a needle axis between a retracted position, wherein at least a tip of the injection needle is contained within the injector housing, and an injection position, wherein at least the tip of the injection needle protrudes from the injector housing through the opening in the base surface; and an activation button assembly movably mounted to the injector housing and operatively connected to the injection needle, the activation button assembly being translatable along a button axis, parallel to the needle axis, from an unactuated position to an actuated position, an external surface of the activation button assembly being depressed below the top surface of the injector housing in the actuated position; the wearable injector being characterized by a biasing member connected with the activation button assembly and the injection needle, the biasing member being stabilized in a stored energy state in the unactuated position of the activation button assembly, and released in the actuated position of the activation button assembly into an energy releasing state to drive the injection needle along the needle axis from the retracted position thereof to the injection position thereof, wherein: a position of the activation button assembly between the unactuated position thereof and the actuated position thereof defines a threshold point, in the stored energy state, the biasing member biases the activation button assembly into the unactuated position thereof and returns the activation button assembly to the unactuated position in response to movement of the activation button assembly not surpassing the threshold point; and movement of the activation button assembly beyond the threshold point secures the activation button assembly in the depressed actuated position. an injector housing comprising a base surface and an opposing top surface, the base surface being configured to contact a skin surface of a user and having an opening therein, and the top surface defining an opening therethrough; an injection needle mounted within the injector housing and translatable along a needle axis between a retracted position, wherein at least a tip of the injection needle is contained within the injector housing, and an injection position, wherein at least the tip of the injection needle protrudes from the injector housing through the opening in the base surface; and an activation button assembly movably mounted to the injector housing and operatively connected to the injection needle, the activation button assembly being translatable along a button axis, parallel to the needle axis, from an unactuated position to an actuated position, an external surface of the activation button assembly being depressed below the top surface of the injector housing in the actuated position; the wearable injector being characterized by a biasing member connected with the activation button assembly and the injection needle, the biasing member being stabilized in a stored energy state in the unactuated position of the activation button assembly, and released in the actuated position of the activation button assembly into an energy releasing state to drive the injection needle along the needle axis from the retracted position thereof to the injection position thereof, wherein: a position of the activation button assembly between the unactuated position thereof and the actuated position thereof defines a threshold point, in the stored energy state, the biasing member biases the activation button assembly into the unactuated position thereof and returns the activation button assembly to the unactuated position in response to movement of the activation button assembly not surpassing the threshold point; and movement of the activation button assembly beyond the threshold point secures the activation button assembly in the depressed actuated position. a position of the activation button assembly between the unactuated position thereof and the actuated position thereof defines a threshold point, in the stored energy state, the biasing member biases the activation button assembly into the unactuated position thereof and returns the activation button assembly to the unactuated position in response to movement of the activation button assembly not surpassing the threshold point; and movement of the activation button assembly beyond the threshold point secures the activation button assembly in the depressed actuated position.