If you would like a good shampoo for the hairloss I would recommend you to have a look at this website:
What is the best shampoo for hair loss? - NiceHair | How To Stop Hair Loss.
the key ingredient here is ketoconazole.
I have never heard of Alpecin. However medically proven out of a study done 80% of male got an increased intensity of hair were 80% (32/40) for the oral finasteride group and 52% (13/25) for the 5% topical minoxidil group.
link of the study: An open, randomized, comparative study of oral finasteride and 5% t... - PubMed - NCBI
I hope you understand my grammar ^^