Evaluation of the penetration of caffeine from caffeine-containing shampoos into the skin and hair follicles

The hormone dihydrotestosterone (DHT), of which everyone has more or less on their scalp, is a form of testosterone and is responsible for hair loss. The hereditary hypersensitivity of the hair root to the male hormone testosterone is considered the most common cause of hair loss in men (around 95 percent) and in women (80 percent) (androgenetic hair loss). Caffeine can block this hormone to prevent hair loss and promote hair growth by prolonging the hair growth phase. The depth of penetration into the hair follicle is particularly important for the effect of caffeine. The aim of this study is to deliver an increased amount of caffeine into the infundibulum of the hair to enhance the hair growth promoting effect of caffeine. It will be investigated how caffeine is distributed in the skin and the hair follicle. For this purpose, the individual upper skin layers will be removed using the so-called differential tape stripping method with 50 tears of adhesive tape and then subjected to analysis. Finally, cyanoacrylate is applied to the skin and the hair shaft contents are removed and also examined. For these investigations, three different hair washing products are applied to the calf.