The mechanism of action is simple: The small needles of the beard roller puncture the skin. The body recognizes this damage and begins the healing process. Circulation improves, nutrient & hormone-rich blood rushes to the beard area. Since collagen and keratin are both necessary components of the actual facial hair that stems from the follicles, and the androgenic hormones (testosterone and DHT) fuel the growth. It would make logical sense that this could result in an increased rate of natural beard growth, making your mane thicker over time. Micro-needling combined with a few other beard growth hacks belongs to the top methods of fixing a patchy beard.