A few weeks ago, I begain to suspect that my vitamins were causing me to gain weight, or at the very least preventing me from losing weight. I was on a 1200 calorie diet, which I've always easily lost weight on in the past, and could not figure out why I stopped losing weight, and even put a couple pounds back on at some point. Eventually I remembered my sister complaining last year about her multivitamin causing her to gain weight, so it made me suspicious of my vitamins. At the time I was taking MSM, GNC hair, skin & sails, Biotin, and a multivitamin. I stopped taking the multivitamin, hair vitamin and the MSM (it was wreaking havoc on my cycle), and continued with the Biotin and added Super B-Complex. Within 4 days or so, I began losing weight again, and this was the only thing I changed, so it had to be the vitamins. I'm assuming it was the multivitamin and/or the hair vitamin, though I suppose it could have been the MSM. I started taking half a dose of the hair vitamin again (1 pill daily instead of 2), and I'm still losing weight. I'm determined to figure out exactly what the culprit is. Anyway, have any of you ladies found that certain vitamins caused you to gain weight, or prevented you from losing weight? If so, which ones were a problem? I've seen it mentioned from time to time in threads here, but couldn't find a thread specifically about this.