Alpecin Double Effect Shampoo fights against dandruff and hair loss hereditary with caffeine complex. In the first step, this Double Effect Shampoo loosens scaly, keratinous cells and thoroughly removes dandruff from the scalp. This clears the way for the caffeine complex. In the second step, the active ingredients penetrate into the hair root and strengthen it against hereditary hair loss.nLeave the product on the scalp for two minutes- from application to rinse.