Huang YL, et al. - In this retrospective study, researchers examined the preoperative donor site evaluation and compared the actual harvested and estimated follicular units in hair transplantation by analyzing data from 65 males with androgenetic alopecia who had follicular unit transplantation. They found that the harvested grafts produce more 1-hair follicular units and less 3-hair follicular units than estimated. In older patients and those who received multiple sessions of hair transplantation, the scalp laxity was lower. It was noted that the follicular unit density was lower in older patients.