MSM is wonderful for me. I have taken MSM for nearly 2 years now (off and on). I would quit taking it, just to see what would happen. It wouldn't take long before my pain and stiffness would return to my knees. I wouldn't want to go through life without MSM. I am able to go through life without pain in my knees when I take MSM on a regular schedule. I have had no problems taking MSM and I take 12,000 mg. a day. I use a powder MSM that I put in my water, which also encourages me to drink the water I need daily. I even use a MSM soap and lotion for my skin. It has helped my skin alot. I can't say enough good things about MSM. This is the first book I bought about MSM and would recommend it to anyone. I've also read many other papers and articles on MSM, plus I've read alot on the internet about MSM. In fact I've bought this book to give to other people. I am always telling the wonders of MSM to people. I wish you well and happy health.