I have tinnitus from taking antibiotics years ago. It died down considerably after a few months, almost disappearing. It still acts up when I take aspirin or listen to loud music for too long. I just want to say, in my experience, I had a huge, almost immediate return of the ringing when I vaped 50/50 and 70/30 juices. In case anyone is wondering if their symptoms are due to vaping, I came to the conclusion that it can't be the nicotine. When I smoked, and when I drink coffee (still do), I never got symptoms. I researched the other ingredients and found a site with a study done on the ototoxicity of propylene glycol: Ototoxicity of propylene glycol in experime... [Am J Otolaryngol. 1980] - PubMed - NCBI
Since I switched to 100% vg juice, the problem has gone away drastically within just three days. I am sitting in a quiet room and can hardly hear the ringing anymore; it is very faint. I will continue to use vg-only juice and if it goes away completely (as it usually does, for me) it's a success story. Just wanted to offer my advice to anyone who is having this issue.