title_body: Caffeine and Hearing loss
upvoted_answer: The site design here won't let me edit or post a comment.
  
  The study you found found an adverse effect in animals with an exceptionally high intake of caffeine. 25 mg/kg would equate to > 2,000 mg for an average adult (U.S. average, 82 kg) which is a huge amount of caffeine, about five times the maximum amount that is generally recognized as safe (GRAS).
  
  Animal data does not always transfer well to human situations. And we have two statistically controlled major studies that are at some odds with the McGill findings.
  
  These findings are interesting but they only suggest areas that merit more research. It is far from certain that the results would be accurate for humans. And even if you were to make that assumption, the only datum that you really have is that people who ingest huge amounts of caffeine, many fold above GRAS may have a slow recovery from acute hearing trauma or tinnitus.
  
  It's not even known if the effects are permanent.