Park AM, Khan S, Rawnsley J. Hair Biology: Growth and Pigmentation. Facial plastic surgery clinics of North America 2018;26:415-24. https://www.sciencedirect.com/science/article/pii/S1064740618300270?via=ihub Healthy hair is vital to identity. Understanding the intricate anatomy and physiology of hair provides insight into the aging process and the eventual loss of either hair pigmentation or hair shafts. Several biologics are available that have enabled altering or slowing the aging process of hair, but, unfortunately, no agent exists that can reverse the natural course. The commonly used biologics are discussed.