just thought i'd add my 2 cents to the discussion. i've been using penetrex on & off for about 2 years and have found it to be immensely beneficial. one thing i might clarify is that the product actually does not contain DMSO...i also had mistakenly assumed that when i started using it and i actually called the company who distributes it and was told that the ingredient in question is actually DMSO2 (with a subscript 2) which is actually the chemical name for MSM. I think if it contained DMSO I might not have tried it due to its complicated reputation. anyway, for the occasional flare up of my neuropathy i can report that it has worked better than any other OTC medication i've used in the past. my recommendation is to give it a try...hope this helps.