I've been taking LDN for about 2 1/2 months, along with several other treatments. I don't know if it is what is preventing my symptoms from progressing, but I wouldn't want to give it up. Supposedly, it is more effective for MS than for PD, but I have seen ancedotal accounts of how it can stop PD progression, and that's good enough for me. It's cheap, too, so it's not a financial burden.