There was an article in the Daily Express about this some time ago which produced the usual "wonder cases" of people who had been cured by this. It claimed that in a one year trial in Germany 81% of sufferers experienced total clearance or substantial alleviation of symptoms.
It is apparently made from extracts of active alkaloids from the Oregon grape which are supposed to inhibit proliferation of skin cells and reduce inflammation. It is considered one of the most powerful herbal antifungals and comes as an ointment, shampoo, conditioner and scalp oil. The article says "M-folia (the name of the product in the shops) may be the answer". I think we've heard that before.
It does seem very expensive so I haven't bothered with it and neither am I recommending it - I merely give this by way of more info for people to decide themselves. whether it's worth trying.