TLDR Yak belly hair has higher porosity and is less stiff than human hair, making it absorb dye better but less suitable as a direct substitute for hair dyeing.
The study investigated the potential of yak belly hair as a substitute for human hair in the development of hair dyes, due to its similar chemical composition and reduced fluorescence in Raman spectroscopy. Various methods were used to compare the two hair types, including Raman spectroscopy, small-angle X-ray scattering, microscopy, density measurements, and tensile tests. The findings revealed that while human and yak belly hair are similar on a molecular level, they differ significantly in other aspects. Yak belly hair exhibited a smaller intermediate filament distance at the nanoscale, higher porosity across all structural levels, and a lower Young’s modulus, indicating less stiffness. The higher porosity and fewer overlapping scales on yak belly hair facilitate dye uptake but also complicate the comparison of dyeing processes with human hair, limiting its suitability as a replacement.
15 citations,
June 2019 in “JEADV. Journal of the European Academy of Dermatology and Venereology/Journal of the European Academy of Dermatology and Venereology” Chemical and physical treatments like bleaching, dyeing, and UV radiation damage both Caucasian and Afro-ethnic hair.
40 citations,
May 2016 in “Proceedings of the National Academy of Sciences of the United States of America” Changes in keratin make hair follicles stiffer.
24 citations,
November 2015 in “Scientific reports” Human hair has a new region with ordered filaments and the cuticle contains β-keratin sheets.
254 citations,
January 2007 in “Chemical Society Reviews” Hair is a complex protein fiber with unique properties useful for developing hair products.
8 citations,
November 2022 in “International Journal of Cosmetic Science” Human hair varies widely and should be classified by curl type rather than race.
2 citations,
July 2023 in “Cosmetics” Surfactants in shampoos and conditioners remove some but not all lipids from hair, and more research is needed to understand their full impact.
2 citations,
February 2023 in “International journal of molecular sciences” Body hairs can be used in forensic science and toxicology like scalp hair.
63 citations,
February 2017 in “ACS biomaterials science & engineering” Polydopamine is a safe, effective, and permanent hair dye that turns gray hair black in one hour.
Understanding hair surface properties is key for effective hair care products.
