In vitro determination of Mexican Mestizo hair shaft diameter using optical coherence tomography

Mexican mestizo population has a pluriethnic mixture of Amerindian, European and African ancestry, predominant in most Latin American countries. Until now, there are no reports about hair characteristics in this population, necessary to define normal values, for hair diseases evaluation and comparison among other ethnic groups.

The VivoSight^® swept-source multibeam optical coherence tomography system was used to evaluate hair diameter and shape in 30 females. Three hair samples from each volunteer were measured transversely along three distances, generating nine cross-sectional images, two measurements per image and 18 measurements per patient for a total of 540 diameter measurements.

Minimum hair diameter (n = 540) was 0.06 mm while maximum was 0.14 mm. Mean diameter was 0.10 ± 0.01 mm as compared with Asian hair, which ranges from 0.08 mm to 0.12 mm. On morphological analysis, Mexican Mestizo hair tends to have a round shape with homogenous diameters, resembling Caucasian and Asian hair.

Mexican hair is similar to Asian hair in diameter and shape and can be classified as 'thick' hair, which make it more resistant and with more volume. Cosmetic products intended to improve hair care in this population must to consider this characteristic.