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To the Editor: We greatly appreciate the comments from Kim et al regarding ''The effect of platelet-rich plasma on female androgenetic alopecia: A randomized controlled trial.'' 1 With regard to the magnification used in the study, Kim et al suggest the use of a 103 to 153 magnification to evaluate hair density and caliber. We chose to use a 503 magnification for the measurement of hair density and a 1003 magnification for the measurement of hair caliber based on recommendations published in other trichographic literature. 2 Standardization of photography is of critical importance when evaluating hair density and caliber. Accordingly, each global photograph in our trial sought to preserve consistency through the use of similar lighting, hairstyling, and photography systems for the duration of the study. As Kim et al suggested, a representative focus point such as a nevus or angioma was used as a landmark to ensure a uniform magnified photographic field at each visit. 1 The coordinate or overlay technique, as described by Kim et al 3 in a recently published article, is another promising means to evaluate hair density and caliber but had not yet been validated during the time frame in which our study was conducted.Kim et al also note that a previous meta-analysis found that finasteride had the greatest impact on hair density, but to a lesser degree than noted in our platelet-rich plasma study 4 ; however, this metaanalysis did not include platelet-rich plasma and only studied males. In addition, it is unclear if the studies quoted in the meta-analysis used automatic versus manual counting. Several studies have suggested that manual counting is a more accurate means of performing trichographic analysis compared with automatic counting. 5 Accordingly, our study assigned a single study investigator to manually perform the hair density counts on each magnified Folliscope 2.8 (Anagen Corp, Seoul, Korea) image, the values of which were used by the Folliscope 2.8 program to generate a calculated hair density per 1 cm 2 .Our manual counting process also serves to address the concerns Kim et al expressed regarding the lack of hair trimming before our tallying process, as this methodology ensured that only hair follicles observed emerging from the hair scalp were included in our assessment of hair density.We echo the sentiments of Kim et al that standardized and consistent clinical photography on both a global and magnified scale is necessary to accurately evaluate the efficacy of various androgenetic alopecia therapies. In addition, as suggested by Kim et al, future studies comparing different treatment modalities head-to-head with multiple metrics of analysis would be a welcome addition to the available literature.