yes. that is the hard part. When you have a symptom, then stop a supplement, and the problems stop........the first thing i would think is.....hmm......wow! that supplement must have been the problem......I've been there too. Just for the heck of it......go on google..........try wording the question like.......what causes heart palpations, blurry eyes, eye flashes, and tinnitus. I wouldn't put in any more words, as google is pretty sensitive to how questions are worded. see if you get any answers that ....might....give you any clues. If google doesn't come up with an answer, re word the question a little. Do NOT specifically ask if B6 could cause the problems, you want more info, to see if anything else could have caused all that, and then you will have..........here we go again......another piece of the puzzle. in the mid 90's, i had a lot of black specks in my eyes, went to a retinal specialist., he had to do laser surgery immediately, as i almost had a detached retina. At least it only took a couple of minutes to do. He said, if i had flashes, or something like a curtain coming down over my eyes, or anything like that , to go back immediately. did you see a retina specialist for your eye problems? I never knew there were so many things that can happen to eyes.........However, years ago, if my flashes , went away, I don't think i would have followed up with a specialist, I would have been thinking stopping that supplement was the cause..........I take melatonin. sometimes it helps, other times not at all. most i've taken was 6mg. Was any other things in the supplement besides B6?