Test regarding the penetration of caffeine from the caffeine-based 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.


As the largest organ of the body, the skin is made up of several layers and numerous invaginations, so-called hair follicles, from which hairs periodically grow. The scalp is home to around 120,000 such hair follicles which act as stores for active ingredients. In a clinical study it was proven under practical conditions that, after a brief exposure period, due to the network of capillaries, dendritic cells and stem cells surrounding the hair follicles, caffeine favours penetration into the scalp via these follicles and can still be found there even after 24 hours.

One assumes that this path is the faster and also the most effective with regards to the ability to store substances in a long-term depot. The effectiveness of caffeine in combating hormone-related hair loss in the hair roots has already been successfully proven in numerous studies.


In a clinical study at the Center for Experimental and Applied Skin Physiology of the University Clinic Charité, Berlin, the caffeine-based shampoo from Plantur 21 was applied daily to the scalp by ten test subjects. After an exposure time of two minutes, the excess was rinsed off and the hair was towel-dried.

The penetration of the shampoo into the scalp was measured using a modern laser microscope. To make the shampoo visible under the microscope, a fluorescent marker substance was added.


After an exposure time of two minutes and subsequent washing, it was noted that elements of the shampoo had penetrated into the hair follicles (see figure). All the hair follicles in the skin area treated contained the fluorescence dye.

Furthermore, the same concentration of fluorescence seen immediately after application was still present 24 hours later, although the skin had already been in contact with other textiles during the night. There was no trace of the caffeine shampoo build-up in the hair follicles after 48 hours. 


The researchers concluded that the active caffeine from the caffeine-based shampoo formula from Plantur 21 is able to penetrate effectively into the scalp and take effect there thanks to its special composition. If the caffeine-based shampoo from Plantur 21 is used on a daily basis, the caffeine is stored in the hair follicles for at least 24 hours.