A syringe, comprising: a syringe body having a syringe barrel configured to receive and administer a medicament; a hollow needle fluidly communicating with the syringe barrel; and a needle adapter disposed on the syringe body, an outer diameter of the needle adapter being wider than an outer diameter of the syringe barrel; wherein a flat distal surface of the needle adapter facilitates a flush alignment of the distal surface of the needle adapter with at least one of a vial stopper and a vial stopper holder of a medicament vial to ensure that a tip of the needle is inserted at a 90 degree angle into the vial to aspirate the medicament within the vial; characterized by: the needle being fixed relative to the syringe body and the needle adapter; the flat distal surface of the needle adapter controlling depth of insertion of the needle into a user's skin as well as into the medicament vial; the syringe further comprising a vial adapter connected to the syringe and configured to engage a portion of the medicament vial to centrally align axes of the needle and the medicament vial; wherein the vial adapter is configured to slide relative to the needle adapter along an axis parallel to a longitudinal axis of the needle; and wherein the vial adapter comprises: a sliding guide portion configured to slide along the syringe barrel; and a clip portion fixedly connected with the sliding guide portion and being configured to laterally clip onto a neck portion of the medicament vial. a syringe body having a syringe barrel configured to receive and administer a medicament; a hollow needle fluidly communicating with the syringe barrel; and a needle adapter disposed on the syringe body, an outer diameter of the needle adapter being wider than an outer diameter of the syringe barrel; wherein a flat distal surface of the needle adapter facilitates a flush alignment of the distal surface of the needle adapter with at least one of a vial stopper and a vial stopper holder of a medicament vial to ensure that a tip of the needle is inserted at a 90 degree angle into the vial to aspirate the medicament within the vial; characterized by: the needle being fixed relative to the syringe body and the needle adapter; the flat distal surface of the needle adapter controlling depth of insertion of the needle into a user's skin as well as into the medicament vial; the syringe further comprising a vial adapter connected to the syringe and configured to engage a portion of the medicament vial to centrally align axes of the needle and the medicament vial; wherein the vial adapter is configured to slide relative to the needle adapter along an axis parallel to a longitudinal axis of the needle; and wherein the vial adapter comprises: a sliding guide portion configured to slide along the syringe barrel; and a clip portion fixedly connected with the sliding guide portion and being configured to laterally clip onto a neck portion of the medicament vial. the needle being fixed relative to the syringe body and the needle adapter; the flat distal surface of the needle adapter controlling depth of insertion of the needle into a user's skin as well as into the medicament vial; the syringe further comprising a vial adapter connected to the syringe and configured to engage a portion of the medicament vial to centrally align axes of the needle and the medicament vial; wherein the vial adapter is configured to slide relative to the needle adapter along an axis parallel to a longitudinal axis of the needle; and wherein the vial adapter comprises: a sliding guide portion configured to slide along the syringe barrel; and a clip portion fixedly connected with the sliding guide portion and being configured to laterally clip onto a neck portion of the medicament vial. a sliding guide portion configured to slide along the syringe barrel; and a clip portion fixedly connected with the sliding guide portion and being configured to laterally clip onto a neck portion of the medicament vial.