It was recommended recently by a client and I bought it because it has so many stars by it on Amazon. I was convinced I had B12 deficiency because when I took it, most of my typical b12 deficiency symptoms left (and my lifelong soft nails became strong!). The author, Anthony William, described Epstein Barr Virus and the course of the disease and it perfectly fitted what I was suffering from. He sets out a course of treatment that I am now following. Part of that is taking B12 methylcobalamin and adenosylcobalamin. As yet I have nothing to report, but perhaps others might like to read his book, though I should say that the title reveals the source of his information: The Medical Medium. The information within it though is, by my estimation, mind blowingly accurate, making me trust the suggestions he gives for getting better.