Please be careful with this stuff. A relative, also a veternarian, treated himself with dmso. It left him with a very nasty looking burn on his hand. I informed him that dmso was an industrial solvent. He curtly reminded me he was a doctor in animal medicine and he knew what was best. I have used Biofreeze for a few years for cramped and sore muscles . I think it works pretty darn good, especially for neck and shoulder pains that you know will sooner or later turn into those tension headaches.