Would Med schools like to see you do a post bacc or a master’s program in any area you want? Which one would better boost your chances?
Well consider that they are two different programs.
Post Bacc is to increase your ugrad gpa.
Masters is for further study in a field.
I believe Med schools mainly care about undergrad gpa so they want to see a strong gpa. If you have to do a Post Bacc to accomplish this you can do it.
However, comparing someone who did a Post Bacc vs a Masters would be hard. The Masters might give a little edge, but then the whole profile would have to be looked at including MCAT score, ECs, volunteering etc.
I think Post Bacc might be the best approach, at least a friend of mine did that successfully. Found this list of all the programs and courses which might be of help to you: https://■■■■■■■■■■■■■■■■■■■■■■■■■■/blog/an-all-inclusive-list-of-postbac-premedical-programs