For those looking to improve the look of scars, boost collagen, or encourage hair growth, microneedling can offer a minimally invasive solution. The practice dates back to 1995, but has gained significant traction in recent years thanks to new technology. Simply put, microneedling is the insertion of very fine short needles into the skin for the purposes of rejuvenation, explains Macrene. The most popular (and cost effective) microneedling device, known as a dermaroller, is made up of micro-fine needles that range in diameter from 0.5 and 2.5 millimeters. But, if the prospect of multiple needle wounds sounds slightly ominous to you, know that the punctures are more like pin-pricks that enter only surface-level deep.