Test regarding the penetration of caffeine from the caffeine-containing shampoo formula by Plantur 21

Conducted at the Center for Experimental and Applied Cutaneous Physiology and Clinical Research Center for Hair and Skin Science at the Charité University Clinic, Berlin.


The skin, as the body’s largest organ, is comprised of multiple layers and has numerous invaginations, the so-called hair follicles from which hairs grow periodically. The scalp has about 120,000 such hair follicles, which may serve as storage for active ingredients.

In a clinical test, it was proven under practical conditions that, after a short residence time, caffeine preferably penetrates the scalp through these hair follicles due to the surrounding network of capillaries, dendritic cells and stem cells and can still be detected there after 24 hours.

It is assumed that this path is quicker and most effective, also with regard to the ability to store substances in a long-term depot.


In the clinical test at the Center for Experimental and Applied Cutaneous Physiology of the Charité in Berlin, the caffeine-containing shampoo by Plantur 21 was applied to the scalp daily by 10 test subjects. After a residence time of two minutes, the excess was rinsed out and the hair was dried with towels.

Penetration of the shampoo into the scalp was measured with a modern laser microscope. To make the shampoo visible under the microscope, a fluorescent tracer substance was previously added.


After a residence time of two minutes and the concluding rinse process, it was ascertained that components of the shampoo had penetrated into the hair follicles (see figure). All hair follicles of the treated skin surface contained the fluorescent dye.
Furthermore, fluorescence in the same concentration was ascertained immediately upon application and after 24 hours, even though the skin was already in contact with other textiles during the night. The reserve of the Caffeine Shampoo in the hair follicles was no longer detectable after 48 hours.

Localization of the fluorescent dye after two minutes residence time and rinsing


The researchers came to the conclusion that the active caffeine from the caffeine-containing shampoo formula by Plantur21 can penetrate into the scalp based on its special composition and unfold its effect there. If the caffeine-containing shampoo by Plantur21 is applied daily, the caffeine is stored in the hair follicles for at least 24 hours.