Human hair follicles traverse the epidermis and dermis, and are comprised of specialised cells including dermal papilla cells (DPCs).

DPCs play a critical role in the development and growth of both hair and follicle structure.

While exposure of DPCs to undiluted exogenous compounds is unlikely, exposure to diluted compounds is possible should dermal penetration occur.

The goal of this study was to evaluate the impact on hair and scalp health following application of a hair care product.

Due to the lack of standardised and validated test systems for evaluating hair follicle health, the HairSkin^® model, which uses intact human scalp samples, was adapted to evaluate hair follicle and scalp health.

Similarly, the Franz diffusion cell assay and matrix-assisted laser desorption ionisation-Fourier transform ion cyclotron resonance (MALDI-FTICR) were adapted to evaluate dermal penetration.

The results of this study demonstrate that application of the hair care product does not result in appreciable dermal penetration, suggesting that DPCs are unlikely to be exposed to undiluted product.

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