The challenge of shaving is to cut the beard hair as closely as possible to the skin without unwanted effects on the skin. To achieve this requires the understanding of beard hair and male facial skin biology as both, the beard hair and the male facial skin, contribute to the difficulties in obtaining an effective shave without shavinginduced skin irritation. Little information is available on the biology of beard hairs and beard hair follicles. We know that, in beard hairs, the density, thickness, stiffness, as well as the rates of elliptical shape and low emerging angle, are high and highly heterogeneous. All of this makes it challenging to cut it, and shaving techniques commonly employed to overcome these challenges include shaving with increased pressure and multiple stroke shaving, which increase the probability and extent of shaving-induced skin irritation. Several features of male facial skin pose problems to a perfect shave. The male facial skin is heterogeneous in morphology and roughness, and male skin has a tendency to heal slower and to develop hyperinflammatory pigmentation. In addition, many males exhibit sensitive skin, with the face most often affected. Finally, the hair follicle is a sensory organ, and the perifollicular skin is highly responsive to external signals including mechanical and thermal stimulation. Perifollicular skin is rich in vasculature, innervation and cells of the innate and adaptive immune system. This makes perifollicular skin a highly responsive and inflammatory system, especially in individuals with sensitive skin. Activation of this system, by shaving, can result in shaving-induced skin irritation. Techniques commonly employed to avoid shaving-induced skin irritation include shaving with less pressure, pre-and post-shave skin treatment and to stop shaving altogether. Recent advances in shaving technology have addressed some but not all of these issues. A better understanding of beard hairs, beard hair follicles and male facial skin is needed to develop novel and better approaches to overcome the challenge of shaving. This article covers what is known about the physical properties of beard hairs and skin and why those present a challenge for blade and electric shaving, respectively.R esum e Le d efi du rasage est de couper les cheveux de la barbe aussi pr es que possible de la peau sans effets ind esirables sur la peau. Atteindre cet objectif exige la compr ehension de la biologie des poils de barbe et de la peau du visage mâle, puisque les cheveux de la barbe et la peau du visage masculin contribuent aux difficult es a obtenir un rasage efficace sans une irritation cutan ee induite. Peu d'informations sont disponibles sur la biologie des poils de barbe et les follicules pileux de la barbe. Nous savons que, dans les poils de la barbe, la densit e, l' epaisseur, la rigidit e, ainsi que les taux des formes elliptiques et d'un faible angle emergent sont elev es et tr es h et erog enes. Tout cela fait qu'il est difficile de les couper, et des techniques de rasage coura...

Globally, millions of men regularly remove their facial hair using an electric shaver. Over the course of several decades, the concept of an electric shaver has evolved from a relatively simple hand-powered apparatus to a technologically advanced device designed to provide the user with an optimum shaving experience. This requires a careful balance between robust removal of hair and skin comfort. By incorporating advanced scientific measurement and imaging technology into clinical testing, insights are being gained into skin comfort issues associated with hair removal practices. This study describes new research insights that have guided the development of electric shaving technology. These innovative features are designed to maximize hair removal and minimize the impact on skin health, thus enabling new levels of shaving efficacy and comfort to be attained.