Is this a Jaco Blab spam? Actually I think the FDA does not approve of DMSO in any form for use in or on humans (except for one obscure use in one specific form obtainable by a medical professional only and administered as well.) I don't think 99 or 99.9 or 99.98% is going to do what it does any differently. The problem with lower purity is: What does that other part consist of? Because whatever it is, DMSO is going to carry it deep into your body, past the skin and other protective barriers. I've used 99.9% bought from a reputable but cheap dealer. I've had no side effects, it works OK for joint pain, but not as good, by a long shot, as Ibuprofren. Of course, it doesn't destroy your stomach or liver like Ibuprofren does.