Can I enhance the effectiveness of Caffeine Shampoo if I leave it in for more than 2 minutes?
The efficacy of a caffeine-containing shampoo to treat hereditary hair loss was demonstrated in scientific studies [in vivo] after being left on for just two minutes – from application to rinsing out. The presence of stimulating caffeine was confirmed after just 120 seconds which means there is no need to leave the product in for longer. A study [Charite] has, however, shown that absorption of the active ingredient increases for a period of up to 30 minutes. After that, penetration via the skin surrounding the follicles increases to such an extent that an additional caffeine supply is ensured for up to about eight hours.
If the product is left on the scalp for longer than 2 minutes, check your scalp type and scalp condition. Depending on the scalp's sensitivity, leaving the product on excessively long can result in temporary redness. To achieve a particularly intensive protective effect, we therefore recommend the combined use of Alpecin Caffeine Shampoo C1 and Alpecin Caffeine Liquid.