I do this all the time and it's never been questioned. My vitamins are green in color, so maybe it's obvious that they're vitamins, idk. I can't imagine it being an issue though!
I put all my meds in individual small "pill baggies" and throw them in my carry on, never a problem. I suppose if you were carrying large amounts of something it could raise an eyebrow , but I think they are looking for bombs, weapons, and of course the always lethal bottle of shampoo.
I have a very large pill box with separate spaces for a full week. I load it up for a weeks worth of meds and vitamins and put it in my carryon. The rest I have in checked luggage.
Just an FYI, the TSA recommends keeping meds in their original packaging, I assume it's the same for vitamins. Most people never do and never have an issue. I do now since they seized my magnesium and potassium pills about 5 years ago when they were just in a little plastic container. Guess they looked suspicious? Maybe the screening officer was in a bad mood? Definitely takes up more space but I'm paranoid now.
Between my son and me, we have a ton of different prescription and vitamin pills that we routinely travel with in unmarked organizers. I might have to check a bag if I were to bring all of the original containers. No one has ever raised an eyebrow. I think the TSA has more important concerns.
I bring all my vitamins (and my one med) in original containers in my carry on...last trip, I had about 10 bottles in my carryon bag (since I also had my spouse's vitamins) - it was no problem...
I take seven pills a day plus insulin. I have all the pills in a pill organizer in my backpack, no one has ever said a word to me. Might help that I'm Pre-check.
My attitude is, I carry any medicine that I absolutely need in original packaging, so that (a) it is less likely to be confiscated and (b) it is easier to replace if necessary. I am willing to carry over-the-counter medicines that can be repurchased at any local drug store in plastic bags or combined in unlabeled bottles, because it’s not a big deal if they are taken or lost.