A device and method for enhancing skin piercing by microprotrusions involves pre-stretching the skin to enhance pathway formation when the microprotrusions are pressed into the skin. An expandable device includes skin engaging opposite ends that contact the skin surface so that when the device is expanded the skin is stretched. The skin is placed under a tension of about 0.01 to about 10 megapascals, preferably about 0.05 to 2 megapascals. The device has a plurality of microprotrusions which penetrate the skin while the skin is being stretched by the expanded device. Another stretching device employs suction for skin stretching.