Hair loss treatment center

A lady in her early twenties has considerable hair loss and treatments attempted in several places in two countries yielded no results. She asked me to search for the best specialized center in Germany or Belgium. I've searched the internet, called a couple of centers, a dermatologist and a university professor of dermatology. There are many places to go, but I couldn't get an indication of a treatment center that has the reputation of being THE place to go. Does anyone have any suggestions?