Viva, Hi! No, I haven't researched this particular aspect. ALL that I can say is, Dr. Schulze saw INCREDIBLE SUCCESS with those, who had various Neurological PROBLEMS (M.S., M.D., C.P. A.L.S., Polio, ...) who did his "INCURABLES" Program and took his Nerve Stimulative and Restorative Tonic. By the way, the F.D.A BANNED Dr. Schulze from making his POWERFUL Tonic at his American Botanical Pharmacy. You can go to the Web-Page Link below to see his Formula Recipe though, so that you can make his Tonic for your Friend!