Abstract:

With the increasing incidence of hair loss and especially among younger population in recent years, the demand for diversified products on anti-hair loss solutions is growing and the market of cosmetic products expanding accordingly. Worldwide attention is being paid to the research and development of anti-hair loss actives, while there is no unified standard for the efficacy evaluation and testing methods of anti-hair loss cosmetics. Therefore, it is critical to establish standardized methodology for assessing the effectiveness of anti-hair loss actives and their cosmetic products. In this review, an overview of the human hair follicle structure, the hair follicle cycle, and the biological pathways and signaling mechanisms involved in hair growth are summarized. This provides the fundamental understanding of human hair growth for reviewing anti-hair loss actives and cosmetic hair loss products, and respective methods and techniques applied for evaluating their efficacy. Additionally, changes in the normal hair cycle, and corresponding cosmetic strategies to slow down and reduce hair loss have been provided. This review aims to provide recommendations for evaluating the effectiveness of anti-hair loss actives on the mechanisms involved in the hair follicle growth cycle, and so provide criteria for new technology development and scientific research for cosmetic products.

Key words: anti-hair loss, cosmetic evaluation, functional cosmetic materials, hair follicle growth cycle