Polyphenol-Rich Olive Mill Wastewater Extract and Its Potential Use in Hair Care Products

In this work, the influence of phenol-enriched olive mill wastewater (OMWW) extract on hair growth was investigated in vitro on human follicle dermal papilla cells. OMWW has already shown great potential for use in skincare products, and its high polyphenol content is predestined to have a positive effect on hair growth. The studies included caffeine, a positive modulator of hair growth, and dihydrotestosterone, which causes hair loss in vivo, as controls. The impact of the investigated compounds on hair growth was eva-luated by studies on cell viability and proliferation, the release of growth factors (insulin-like growth factor-1 and vascular endothelial growth factor), and the reduction of reactive oxygen species formation. OMWW showed a positive influence on the proliferation of the human follicle dermal papilla cells. Moreover, the extract leads to a significantly increased secretion of insu-lin-like growth factor-1, and a considerable reduction in reactive oxygen species formation was observed. Overall, our results show that the investigated phenol-enriched OMWW extract is a promising ingredient for hair care to improve hair growth, prevent hair loss due to oxidative stress and maintain a healthy scalp.