Yes, I had severe tinnitus, and took ring stop for about a year. It does really help. Once it took hold, I was silent. (seemed to take about 2 months)
I have now retired, stopped taking it and only have a slight problem. I know if I got back on it I would be silent again. Just not into taking pills and not that bothered.
I don't recall having any side effects from it. Hope this helps.