Defining ideal anterior hairline contour and hair-bearing proportion via a morphometric analysis in Chinese women.

OBJECTIVE: This study aimed to determine the ideal morphology of the anterior hairline contour and hair-bearing proportion in Chinese females, thereby improving preoperative planning protocols and enhancing clinical efficacy in both surgical hair transplantation and non-surgical camouflage interventions. METHODS: Ninety participants completed a questionnaire-based study using digitally modified images of a female model. First, participants were randomly recruited to rate digitally altered images to investigate the most aesthetically preferred hairline contours. Five hairline contours (round, M-shaped, triangular, rectangular, and bell-shaped) were assessed across five dimensions: overall impression, naturalness, attractiveness, youthfulness, and agreeableness (on a 0-10 scale). Subsequently, respondents were asked to adjust the anterior hair-bearing proportion in the image until they reached their highest level of satisfaction. The height ratio (HR) and width ratio (WR) were calculated to quantify the hair bearing proportion. RESULTS: Round, triangular, and M-shaped hairline contours were rated significantly higher than rectangular and bell-shaped contours in terms of overall appearance, naturalness, attractiveness, youthfulness, and agreeableness (all p < 0.001). The most preferred hair-bearing proportion corresponded to an HR of 0.505(IQR 0.455-0.584) and a WR of 0.373(IQR 0.356-0.387). CONCLUSION: Participants demonstrated a clear preference for round anterior hairline contours, with triangular and M-shaped contours also considered aesthetically favorable. An HR of approximately 0.505 and a WR of 0.373 represent the optimal anterior hair-bearing proportions. These population-specific findings provide quantitative evidence to support individualized planning for hair transplantation and nonsurgical aesthetic interventions.