Non-ablative lasers have gained immense popularity in recent years because they require little to no healing time. They work bypassing the surface of the skin and treating the layers underneath, known as the papillary dermis. This allows the skin to respond as if it were repairing a wound and skin regenerates. With this technique, the epidermis is generally not removed. Because they are less intense than ablative lasers, non-ablative procedures pose minimal downtime and recovery. One popular type of non-ablative laser uses an infrared light source that penetrates through the dermis to generate collagen and cause skin contraction and tightening. Non-ablative treatments require multiple sessions and may take several weeks after the last session for the optimal results of treatment to be seen.